[Federal Register Volume 79, Number 206 (Friday, October 24, 2014)]
[Rules and Regulations]
[Pages 63671-63748]
From the Federal Register Online via the Government Publishing Office [www.gpo.gov]
[FR Doc No: 2014-25190]



[[Page 63671]]

Vol. 79

Friday,

No. 206

October 24, 2014

Part II





Department of the Interior





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Fish and Wildlife Service





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50 CFR Part 17





Endangered and Threatened Wildlife and Plants; Threatened Species 
Status for Dakota Skipper and Endangered Species Status for Poweshiek 
Skipperling; Final Rule

Federal Register / Vol. 79 , No. 206 / Friday, October 24, 2014 / 
Rules and Regulations

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DEPARTMENT OF THE INTERIOR

Fish and Wildlife Service

50 CFR Part 17

[Docket No. FWS-R3-ES-2013-0043; 4500030113: 4500030113]
RIN 1018-AY01


Endangered and Threatened Wildlife and Plants; Threatened Species 
Status for Dakota Skipper and Endangered Species Status for Poweshiek 
Skipperling

AGENCY: Fish and Wildlife Service, Interior.

ACTION: Final rule.

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SUMMARY: We, the U.S. Fish and Wildlife Service (Service), determine 
threatened species status under the Endangered Species Act of 1973 
(Act), as amended, for the Dakota skipper (Hesperia dacotae), a 
butterfly currently found in Minnesota, North Dakota, South Dakota, 
Manitoba, and Saskatchewan and endangered species status for the 
Poweshiek skipperling (Oarisma poweshiek), a butterfly currently found 
in Michigan, Minnesota, Wisconsin, and Manitoba. The effect of this 
regulation will be to add these species to the List of Endangered and 
Threatened Wildlife.

DATES: This rule becomes effective November 24, 2014.

ADDRESSES: This final rule is available on the internet at http://www.regulations.gov and http://www.fws.gov/midwest/Endangered/. 
Comments and materials we received, as well as supporting documentation 
we used in preparing this rule, are available for public inspection at 
http://www.regulations.gov. All of the comments, materials, and 
documentation that we considered in this rulemaking are available by 
appointment, during normal business hours at: U.S. Fish and Wildlife 
Service, Twin Cities Field Office, 4101 American Boulevard East, 
Bloomington, Minnesota 55425; (612) 725-3548; (612) 725-3609 
(facsimile).

FOR FURTHER INFORMATION CONTACT: Peter Fasbender, Field Supervisor, 
Twin Cities Field Office, 4101 American Boulevard East, Bloomington, 
Minnesota 55425; (612) 725-3548; (612) 725-3609 (facsimile). Persons 
who use a telecommunications device for the deaf (TDD) may call the 
Federal Information Relay Service (FIRS) at 800-877-8339.

SUPPLEMENTARY INFORMATION: 

Executive Summary

    Why we need to publish a rule. Under the Endangered Species Act, a 
species may warrant protection through listing if it is endangered or 
threatened throughout all or a significant portion of its range. 
Listing a species as an endangered or threatened species can only be 
completed by issuing a rule.
    This rule will finalize the listing of the Dakota skipper (Hesperia 
dacotae) as a threatened species and the Poweshiek skipperling (Oarisma 
poweshiek) as an endangered species.
    The basis for our action. Under the Endangered Species Act, we can 
determine that a species is an endangered or threatened species based 
on any of five factors: (A) The present or threatened destruction, 
modification, or curtailment of its habitat or range; (B) 
Overutilization for commercial, recreational, scientific, or 
educational purposes; (C) Disease or predation; (D) The inadequacy of 
existing regulatory mechanisms; or (E) Other natural or manmade factors 
affecting its continued existence. We have determined the threats to 
both species include:
     Habitat loss and degradation of native prairies and 
prairie fens, resulting from conversion to agriculture or other 
development; ecological succession and encroachment of invasive species 
and woody vegetation primarily due to lack of management; past and 
present fire, haying, or grazing management that degrades or eliminates 
native prairie grasses and flowering forbs; flooding; and groundwater 
depletion, alteration, and contamination.
     Other natural or manmade factors, including loss of 
genetic diversity, small size and isolation of sites, indiscriminate 
use of herbicides such that it reduces or eliminates nectar sources, 
climate conditions such as drought, direct mortality from fire and 
other management activities or natural occurrences, direct or indirect 
mortality from indiscriminate use of pesticides, and other unknown 
stressors.
     Existing regulatory mechanisms are inadequate to mitigate 
these threats to both species.
    Peer review and public comment. We sought comments from independent 
specialists to ensure that our designation is based on scientifically 
sound data, assumptions, and analyses. We invited these peer reviewers 
to comment on our listing proposal. We also considered all other 
comments and information received during the comment period.

Previous Federal Action

    Please refer to the proposed listing rule for the Dakota skipper 
and Poweshiek skipperling (78 FR 63574; October 24, 2013) for a 
detailed description of previous Federal actions concerning this 
species.

Background

    Please refer to the proposed listing rule for the Dakota skipper 
and the Poweshiek skipperling (78 FR 63574; October 24, 2013) for a 
summary of species information.

Status Assessments for Dakota Skipper and Poweshiek Skipperling Dakota 
Skipper

Species Description

    The Dakota skipper (Hesperia dacotae) is a member of the skipper 
family Hesperiidae and was first described in 1911 from collections 
taken at Volga, South Dakota, and Grinnell, Iowa (Skinner 1911 in Royer 
and Marrone 1992a, p. 1). The family Hesperiidae comprises seven 
subfamilies worldwide, four of which occur in North America, north of 
Mexico (Brower and Warren at http://tolweb.org/Hesperiidae). There are 
21 recognized species in the genus Hesperia (ibid). Dakota skipper is 
the accepted common name for H. dacotae.
    The Dakota skipper is a small to medium-sized butterfly with a 
wingspan of 2.4-3.2 centimeters (cm) (0.9-1.3 inches (in)) and hooked 
antennae (Royer and Marrone 1992a, p. 3). Like other Hesperiidae 
species, Dakota skippers have a faster and more powerful flight than 
most butterflies because of a thick, well-muscled thorax (Scott 1986, 
p. 415).
    Adult Dakota skippers have variable markings. The dorsal surface of 
adult male wings ranges in color from tawny-orange to brown and has a 
prominent mark on the forewing; the ventral surface is dusty yellow-
orange (Royer and Marrone 1992a, p. 3). The dorsal surface of adult 
females is darker brown with diffused tawny orange spots and a few 
diffused white spots restricted to the margin of the forewing; the 
ventral surfaces are dusty gray-brown with a faint white spotband 
across the middle of the wing (Royer and Marrone 1992a, p. 3). Adult 
Dakota skippers may be confused with the Ottoe skipper (H. ottoe), 
which is somewhat larger with slightly longer wings (Royer and Marrone 
1992a, p. 3). Dakota skipper pupae are reddish-brown, and the larvae 
are light brown with a black collar and dark brown head (McCabe 1981, 
p. 181).

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General Life History

    Dakota skippers are univoltine (having a single flight per year), 
with an adult flight period that may occur from the middle of June 
through the end of July (McCabe 1979, p. 6; McCabe 1981, p. 180; Dana 
1991, p. 1; Royer and Marrone 1992a, p. 26; Skadsen 1997, p. 3; Swengel 
and Swengel 1999, p. 282). The actual flight period varies somewhat 
across the range of each species and can also vary significantly from 
year to year (e.g., Rigney 2013a, p. 138), depending on temperature 
patterns (Bink and Bik 2009, Koda and Nakamura 2012). Females emerge 
slightly later than males (Dana 1991, p. 15, Rigney 2013a, p. 138), and 
the observed sex ratio of Dakota skippers was roughly equal during peak 
flight periods (Dana 1991, p. 15; Swengel and Swengel 1999, pp. 274, 
283).
    The Dakota skipper flight period in a locality lasts 2 to 4 weeks, 
and mating occurs throughout this period (Braker 1985, p. 46; McCabe 
and Post 1977, pp. 36-38; McCabe 1979, p. 6; McCabe 1981, p. 180; Dana 
1991, p. 15; Swengel and Swengel 1999, p. 282; Rigney 2013a, p. 138). 
Adult male Dakota skippers exhibit perching behavior (perch on tall 
plants to search for females), but occasionally appear to patrol in 
search of mating opportunities (Royer and Marrone 1992a, p. 25).
    Dakota skippers lay eggs on broadleaf plants (McCabe 1981, p. 180) 
and grasses (Dana 1991, p. 17), although larvae feed only on grasses. 
Potential lifetime fecundity is between 180 and 250 eggs per female 
Dakota skipper; realized fecundity depends upon longevity (Dana 1991, 
p. 26). Female Dakota skippers lay eggs daily in diminishing numbers as 
they age (Dana 1991, pp. 25-26). Dana (1991, p. 32) estimated the 
potential adult life span of Dakota skipper to be 3 weeks and the 
average life span (or residence on site before death or emigration) to 
be 3 to 10 days on one Minnesota prairie.
    Dakota skippers overwinter as larvae and complete one generation 
per year. Dakota skipper eggs hatch after incubating for 7-20 days; 
therefore, hatching is likely completed before the end of July. Recent 
research at the Minnesota Zoo demonstrated that, under controlled 
conditions in the laboratory, Dakota skippers eggs hatched after 11 to 
16 days, and the majority of the caterpillars hatched on the 13th and 
14th days (Runquist 2014, pers. comm.). After hatching, Dakota skipper 
larvae crawl to the bases of grass plants where they form shelters at 
or below the ground surface with silk, fastened together with plant 
tissue (Dana 1991, p. 16). They construct 2-3 successively larger 
shelters as they grow (Dana 1991, p. 16). The larvae emerge from their 
shelters at night to forage (McCabe 1979, p. 6; McCabe 1981, p. 181; 
Royer and Marrone 1992a, p. 25) and appear to clip blades of grass and 
bring them back to their shelters to consume (Dana 2012a, pers. comm.).
    Dakota skippers have six or seven larval stages (instars) (Dana 
1991, pp. 14-15) and overwinter (diapause) in ground-level or 
subsurface shelters during either the fourth or fifth instar (McCabe 
1979, p. 6; McCabe 1981, pp. 180, 189; Dana 1991, p. 15; Royer and 
Marrone 1992a, pp. 25-26). In the spring, larvae resume feeding and 
undergo two additional molts before they pupate. During the last two 
instars, larvae shift from buried shelters to horizontal shelters at 
the soil surface (Dana 1991, p. 16).

Food and Water

    Nectar and water sources for adult Dakota skippers vary regionally 
and include purple coneflower (Echinacea angustifolia), blanketflower 
(Gaillardia aristata), black-eyed Susan (Rudbeckia hirta), purple 
locoweed (Oxytropis lambertii), bluebell bellflower (Campanula 
rotundifolia), prairie milkvetch (Astragalus adsurgens) (syn. A. 
laxmannii), and yellow sundrops (Calylophus serrulatus) (Dana 1991; 
McCabe and Post 1977, pp. 36-38; Royer and Marrone 1992a, p. 21; Rigney 
2013a, p. 142). Plant species likely vary in their value as nectar 
sources due to the amount of nectar available during the adult flight 
period (Dana 1991, p. 48). Nectar source preferences are typically 
indicated as the relative proportion of plants selected for nectaring 
among all the available species in a particular area. Swengel and 
Swengel (1999, pp. 280-281) observed nectaring at 25 plant species, 
however, most of the nectaring was at purple coneflower and 
blanketflower. Dana (1991, p. 21) reported the use of 25 nectar species 
in Minnesota with purple coneflower most frequented; McCabe (1979, p. 
42; McCabe 1981, p. 187) observed Dakota skippers using eight nectar 
plants. Dakota skippers in Manitoba were recently observed nectaring on 
12 species of plants, primarily black-eyed Susan, but also including 6 
species that were previously unrecorded as nectar flowers: White 
sweetclover (Melilotus alba), purple prairie clover (Petalostemon 
purpureus), yellow evening-primrose (Oenothera biennis), palespike 
lobelia (Lobelia spicata), fiddleleaf hawksbeard (Crepis runcinata), 
and upland white aster (Solidago ptarmicoides) (Rigney 2013a, pp. 4, 
57). In addition to nutrition, the nectar of flowering forbs provides 
water for Dakota skipper, which is necessary to avoid desiccation 
during flight activity (Dana 1991, p. 47; Dana 2013, pers. comm.). Some 
plant species listed in some studies as nectar flowers are likely used 
for perching and patrolling rather than as nectar sources.
    The flight of the adult female typically extends beyond that of 
males (Dana 2014, pers. comm.; Dana 1991, pp. 1,15; Rigney 2013a, p. 
138); therefore the two sexes can visit the same nectar plant species 
at different rates (e.g., if the flowering period is more coincident 
with either the male or the female flight period). For example, Dana 
(1991, p. 21) observed a greater number of males than females visiting 
purple locoweed--this plant is already past its flowering peak at the 
beginning of the male flight and nearly finished flowering by the peak 
female flight (Dana 2014, pers. comm.).
    Dakota skipper larvae feed on several native grass species; little 
bluestem (Schizachyrium scoparium) is a frequent food source of the 
larvae (Dana 1991, p. 17; Royer and Marrone 1992a, p. 25), although 
they have been found on Dichanthelium spp., and other native grasses 
(Royer and Marrone 1992a, p. 25). When presented with no other choice, 
Dakota skipper larvae may feed on a variety of native and nonnative 
grasses (e.g., Kentucky bluegrass (Poa pratensis)) at least until 
diapause (Dana 1991, p. 17). The timing of growth and development of 
grasses relative to the larval period of Dakota skippers are likely 
important in determining the suitability of grass species as larval 
host plants. Large leaf blades, leaf hairs, and the distance from 
larval ground shelters to palatable leaf parts preclude the value of 
big bluestem and Indian grass as larval food plants, particularly at 
younger larval stages (Dana 1991, p. 46). In captivity, Dakota skipper 
larvae ate big bluestem (Andropogon gerardii), at older larval stages, 
and prairie dropseed (Sporobolus heterolepis) (Runquist 2014, pers. 
comm.). Captive larvae also fed on smooth brome (Bromus inermis) (Dana 
1991, p 17), but this was not tested in a natural setting and the 
structural features of this grass would hinder or prevent larval 
survival (Dana 2013, pers. comm.). The tight empirical correlation 
between occurrence of Dakota skippers and the dominance of native 
grasses in the habitat, indicates that population persistence requires 
native grasses for survival (Dana 2013, pers. comm.).

[[Page 63674]]

Dispersal

    Dakota skipper are not known to disperse widely; the species was 
evaluated among 291 butterfly species in Canada as having relatively 
low mobility. Experts estimated Dakota skipper to have a mean mobility 
of 3.5 (standard deviation = 0.7) on a scale of 0 (sedentary) to 10 
(highly mobile) (Burke et al. 2011, p. 2279; Fitzsimmons 2012, pers. 
comm.). Dakota skippers may be incapable of moving greater than 1 
kilometer (km) (0.6 miles (mi)) between patches of prairie habitat 
separated by structurally similar habitats (e.g., crop fields, grass-
dominated fields or pasture, but not necessarily native prairie) 
(Cochrane and Delphey 2002, p. 6). Royer and Marrone (1992a, p. 25) 
concluded that Dakota skippers are not inclined to disperse, although 
they did not describe individual ranges or dispersal distances. McCabe 
(1979, p. 9; 1981, p. 186) found that concentrated activity areas for 
Dakota skippers shift annually in response to local nectar sources and 
disturbance.
    In a mark-recapture study, average adult movements of Dakota 
skipper were less than 300 meters (m) (984 feet (ft)) over 3-7 days; 
marked adults crossed less than 200 m (656 ft) of unsuitable habitat 
between two prairie patches and moved along ridges more frequently than 
across valleys (Dana 1991, pp. 38-40). Dana (1997, p. 5) later observed 
reduced movement rates across a small valley dominated by exotic 
grasses compared with movements in adjacent widespread prairie habitat. 
Roads and crop fields were suspected as impediments for movement among 
prairie patches along two sites of the main valley (Dana 1997, p. 5), 
although movements beyond the study area were beyond the scope of the 
1997 mark-recapture study (Dana 2013, pers. comm.). Skadsen (1999, p. 
2) reported possible movement of Dakota skippers in 1998 from a known 
population at least 800 m (2625 ft) away to a site with an unusually 
heavy growth of purple coneflower; he had not found Dakota skippers in 
three previous years when coneflower production was sparse. The two 
sites were connected by native vegetation of varying quality, 
interspersed by a few asphalt and gravel roads (Skadsen 2001, pers. 
comm.).
    In summary, the best information we have suggests that dispersal of 
Dakota skipper is very limited due in part to its short adult life span 
and single annual flight. Therefore, the species' extirpation from a 
site is likely permanent unless it is within about 1 km (0.6 mi) of a 
site that generates a sufficient number of emigrants or is artificially 
reintroduced to a site; however, the capability to propagate the Dakota 
skipper is currently lacking.

Habitat

    Dakota skippers are obligate residents of undisturbed (remnant, 
untilled) high-quality prairie, ranging from wet-mesic tallgrass 
prairie to dry-mesic mixed-grass prairie (Royer and Marrone 1992a, pp. 
8, 21). High-quality prairie contains a high diversity of native plant 
species, including flowering herbaceous plants (forbs). Royer and 
Marrone (1992a, p. 21) categorized Dakota skipper habitat into two main 
types that were once intermixed on a landscape scale, but are now 
mostly segregated. The first, referred to as ``Type A'' by Royer et al. 
(2008, pp. 14-16), is low wet-mesic prairie that occurs on near-shore 
glacial lake deposits. Type A Dakota skipper habitat is dominated by 
bluestem grasses, with three other plant species almost always present 
and blooming during Dakota skipper's flight period: Wood lily (Lilium 
philadelphicum), bluebell bellflower, and mountain deathcamas (smooth 
camas; Zigadenus elegans) (McCabe 1981, p. 190). This habitat type has 
a high water table and is subject to intermittent flooding in the 
spring, but provides ``sufficient relief to provide segments of non-
inundated habitat during the spring larval growth period within any 
single season'' (Royer et al. 2008, p. 15). Common forbs in bloom 
during the late season in Type A habitat include Rocky Mountain blazing 
star (Liatris ligulistylis), Canada goldenrod (Solidago canadensis), 
strict blue-eyed grass (Sisyrinchium montanum), common goldstar 
(Hypoxis hirsuta), and black-eyed Susan (Lenz 1999, p. 6). Type A 
habitats also contain small patches of dry-mesic prairie inhabited by 
Dakota skippers. Common forb species in these dry-mesic areas include 
stiff sunflower (Helianthus pauciflorus Nutt. ssp. pauciflorus) and 
candle anenome (Anemone cylindrica), although purple coneflower was 
rare in these habitats (Lenz 1999, pp. 6-11). Dakota skipper inhabits 
Type A habitat in north-central North Dakota, southeast North Dakota, 
and Manitoba.
    The second Dakota skipper habitat type, referred to as ``Type B'' 
by Royer et al. (2008, p. 14), occurs on rolling terrain over gravelly 
glacial moraine deposits and is dominated by bluestems and needle 
grasses (Heterostipa spp.). As with Type A habitat, bluebell bellflower 
and wood lily are also present in Type B habitats, but Type B habitats 
also support more extensive stands of purple coneflower, upright 
prairie coneflower, and common gaillardia (Royer and Marrone 1992a, p. 
22). Both Type A and Type B prairies may contain slightly depressional 
(low topographical areas that allow for the collection of surface 
water) wetlands with extensive flat areas and slightly convex hummocks, 
which are dryer than the wet areas (Lenz 1999, pp. 4, 8).
    In northeastern South Dakota, Dakota skippers inhabit primarily 
Type B habitats with abundant purple coneflower, but they also occur in 
nearby Type A habitats in some areas (Skadsen 1997, p. 4). All Type A 
habitats occupied by Dakota skipper in South Dakota are near hill-
prairie (Type B) habitats that are managed with fall haying (Skadsen 
2006b, p. 2).
    Little bluestem and porcupine grass (Hesperostipa spartea) are the 
predominant grass species in Dakota skipper habitat in South Dakota 
(Skadsen 2006b, p. 2). Dry-mesic prairies suitable for Dakota skippers 
in South Dakota typically include little bluestem, side oats grama, 
porcupine grass, needle-and-thread grass (Hesperostipa comata), and 
prairie dropseed, and a high diversity and abundance of forbs, 
including purple coneflower, purple prairie clover, white prairie 
clover, yellow sundrops, prairie groundsel (Packera plattensis), 
prairie milkvetch, eastern pasqueflower (Pulsatilla patens), old man's 
whiskers (prairie smoke, Geum triflorum), western silver aster 
(Symphyotrichum sericeum), dotted blazing star (Liatris punctata), tall 
blazing star (L. asper), meadow zizia (Zizia aptera), blanket flower, 
prairie sagewort (Artemisia frigida), and leadplant (Amorpha canescens) 
(Skadsen 2006b, pp. 1-2). Purple coneflower occurs at all sites where 
the Dakota skipper has been recorded in South Dakota, although it is 
absent at some sites where Dakota skipper is abundant in other States 
(Skadsen 2006b, p. 2).
    In Minnesota, Dakota skippers often inhabit Type B habitats, 
however, the species has been documented in Type A habitats, 
particularly in Kittson and Stearns counties. Dana (1997, p. 8) 
described typical habitat in Minnesota as dry-mesic prairie dominated 
by mid-height grasses with an abundance of nectar sources including 
purple coneflower and prairie milkvetch (Astragalus laxmannii Jacq. 
var. robustior). Southern dry prairies in Minnesota are described as 
having sparse shrub cover (less than 5 percent) composed primarily of 
leadplant, with prairie rose (Rosa arkansana), wormwood sage, or smooth 
sumac (Rhus glabra) present and few, if any, trees (Minnesota DNR 
2012a). Dana (1991, p. 21) never encountered Dakota

[[Page 63675]]

skippers in wet or wet-mesic prairies in Minnesota, despite abundance 
of suitable plants and the frequent use of these habitats by similar 
skipper species. In systematic surveys at 12 Minnesota sites, Swengel 
and Swengel (1999, pp. 278-279) found that Dakota skippers were 
significantly more abundant on dry prairie than on either wet-mesic 
prairie.
    In Manitoba, Dakota skipper habitat has been described as Type A 
prairies, where the species tends to occupy the slightly higher, drier 
areas of wet-mesic prairie where nectar sources are more abundant 
(Webster 2003, p. 7). Recent studies classify Dakota Skipper sites in 
Manitoba as tallgrass or medium to tallgrass prairies that have been 
subject to minimal disturbance, generally consisting of higher, dryer 
prairies adjacent to lower areas with sedges (Rigney 2013a, p. 155). 
Inhabited areas are dominated by native grasses and sites are generally 
characterized as having the following plant species: Big bluestem, 
little bluestem (Schizachyrium scoparius), tufted hair grass 
(Deschampsia caespitosa), switchgrass (Panicum virgatum), Cusick's 
bluegrass (Poa cusickii), porcupine grass, common spikerush (Eleocharis 
palustris), wood lily (Lilim philadelphicum), wild onion (Allium 
stellatum), mountain death camas (Zygadenus elegans), death camas 
(Zygadenus gramineus), common gold star (Hypoxis hirsute), wild prairie 
rose, American licorice (Glycyrrhiza lepidota), white prairie clover 
(Petalostemon candidum), purple prairie clover, Seneca snake root 
(Polygala senega), meadow zizia, northern bedstraw (Galium boreale), 
harebell, palespike lobelia, common yarrow (Achillea millefolium), pale 
agoseris (Agoseris glauca), heath aster (Aster ericodes) or white 
prairie aster (A. falcatus), smooth aster (Aster laevis), Flodman's 
thistle (Cirsium flodmanii), fiddle leaf hawksbeard, eastern daisy 
fleabane (Erigeron annuus), Maximilian sunflower (Helianthus 
maximilianii), Nuttall's sunflower (Helianthus nuttallii), meadow 
blazing star, black-eyed Susan, upland white aster, and stiff goldenrod 
(Solidago rigida) (Rigney 2013a, pp. 155-156).
    Occupied habitats in Saskatchewan are similar to the drier upland 
dry-mesic mixed-grass prairie hillside habitats in Manitoba, which is 
dominated by bluestems and needlegrass. The Dakota skipper was most 
common on ridgetops and hillsides near purple coneflower (Webster 2003, 
p. 8).
    In North Dakota, an association of bluestems (Schizachyrium 
scoparium, Andropogon gerardii) and needlegrasses, typically invaded by 
Kentucky bluegrass, typifies dry-mesic Dakota skipper habitat in the 
rolling terrain of river valleys and the Missouri Coteau (Royer and 
Marrone 1992a, p. 22). These prairies, located on the western edge of 
the species' known range, typically contain wood lily, bluebell 
bellflower, coneflowers, and other asters as nectar sources; in some 
areas, mountain deathcamas also occurs (Royer and Marrone 1992a, p. 
22). The location of larval food plants rarely seems to affect Dakota 
skipper distribution within habitats because these warm-season grasses 
are usually dominant and evenly dispersed (Swengel 1994, p. 6), 
although invasion by smooth brome grass and other invasive species may 
displace or extirpate native larval food plants (Culliney 2005, p. 134; 
Bahm et al. 2011, p. 240; LaBar and Schultz 2012, p. 177).
    Two key factors, soils unsuitable for agriculture and steep 
topography, have allowed remnant native-prairie habitats inhabited by 
Dakota skippers to persist (Royer and Marrone 1992a, p. 22). McCabe 
(1979, pp. 17-18; 1981, p. 192) and Royer et al. (2008, p. 16) have 
linked the historical distribution of Dakota skippers to surface 
geological features and soils that are glacial in origin and, possibly, 
regional precipitation-evaporation ratios (ratio of evaporation 
occurring naturally in one location over a given area compared to the 
amount of precipitation, such as rain and snow, falling over the same 
area). Soil types typical of Dakota skipper sites were described as 
sandy loams, loamy sand, or loams (Lord 1988 in Royer et al. 2008, pp. 
3, 10). Additional edaphic (soil) features, such as soil moisture, 
compaction, surface temperature, pH, and humidity, may be contributing 
factors in larval survival and, thus, important limiting factors for 
Dakota skipper populations (Royer et al. 2008, p. 2). For example, 
edaphic parameters measured in sites throughout the range of Dakota 
skipper and occupied by the species included a bulk density (an 
indicator of soil compaction) that ranged from 0.9g/cm\3\ to 1.3 g/
cm\3\ and mean soil pH that ranged from 6.3 to 6.7 with high micro-
scale variation (variation on a small scale) (Royer et al. 2008, p. 
10). Soil texture ranged from 4 to 12 percent clay, 53 to 74 percent 
sand, and 14 to 39 percent silt (Royer et al. 2008, p. 12). Seasonal 
soil temperatures, measured at three depths (20, 40, and 60 cm (8, 16, 
and 24 in)) were the same at all depths within a site; occupied 
Minnesota sites generally had higher soil temperatures at all depths 
than occupied sites in North Dakota or South Dakota (Royer et al. 2008, 
p. 11). Royer did not measure these parameters in unoccupied sites.
    Rigney (2013a, pp. 108-109) measured edaphic features at 8 sites in 
Manitoba occupied by the species and broadly characterized the soil 
compaction (at 10 cm) as 570 to 990 kPA, bulk density ranging from 0.75 
to 1.30 kg/L, mean soil surface air temperature at 18 [deg]C during 
Julian weeks 28-39 (continuous count of weeks since the beginning of 
the calendar year), and mean relative humidity at 85 percent during the 
same time period. Soils were classified as clay loams and sandy loams, 
with generally low to moderate compaction (<1375 kPA) and bulk 
densities, which is indicative of little or no compacting forces from 
cattle grazing, tilling, or agricultural vehicles (Rigney 2013a, pp. 
104, 119).
    Royer (2008, pp. 2, 16) hypothesized that Dakota skipper larvae are 
particularly vulnerable to desiccation (drying out) during dry summer 
months and require ``vertical water distribution'' (movement of shallow 
groundwater to the soil surface) in the soils or wet low areas to 
provide relief from high summer temperatures. Humidity may also be 
essential for larval survival during winter months since the larvae 
cannot take in water during that time and depend on humid air to 
minimize water loss through respiration (Dana 2013, pers. comm.). Royer 
(2008, pp. 14-15) measured microclimalogical levels (climate in a small 
space, such as at or near the soil surface) within ``primary larval 
nesting zones'' (0 to 2 cm (0 to 0.8 inches) above the soil surface) 
throughout the range of Dakota skippers, and found an acceptable 
rangewide seasonal (summer) mean temperature range of 18 to 21 [deg]C 
(64 to 70 [deg]F), rangewide seasonal mean dew point ranging from 14 to 
17 [deg]C (57 to 63 [deg]F), and rangewide seasonal mean relative 
humidity between 73 and 85 percent. Royer (2008) only examined occupied 
areas for these parameters; therefore, the statistical and biological 
significance of these edaphic variables cannot be determined from his 
study.

Species Occupancy

    We generally consider the Dakota skipper or Poweshiek skipperling 
to be ``present'' at sites where the species was detected during the 
most recent survey, if the survey was conducted in 2002 or more 
recently and there is no evidence to suggest the species is now 
extirpated from the site (e.g., no destruction or obvious and 
significant degradation of the species' habitat), with the exception

[[Page 63676]]

of the following four sites. We consider the species to be present at 
one Poweshiek skipperling site in Michigan where the species was 
observed at the site in 1996, and no further surveys have been 
conducted. This site, however, still has suitable habitat for the 
species according to species experts in the State and at least one 
other species of prairie-fen-dependent butterfly is present (Hosler 
2013, pers. comm.). Therefore, the Poweshiek skipperling is most likely 
still present at this site. We also consider the Dakota skipper to be 
present at one site (Chanarambie Creek in Minnesota) where the most 
recent survey was from 1994. At this site, no evidence suggests the 
species is not still present because, based on a species-expert review 
of the site, the habitat and management is still conducive to the 
species (Dana 2013, pers. comm.). Additional sites where we consider 
Dakota skipper to be present include two sites in Minnesota with 1996 
records (Bluestem Prairie and Buffalo River State Park). Although no 
survey for the species has taken place at Bluestem Prairie since 1996, 
a 2012 assessment of the habitat at the site indicates that this site 
is a high-quality prairie that contains the native prairie flora 
conducive to the Dakota skipper (Selby 2012, p. 9). The site at Buffalo 
River State park, which adjoins Bluestem Prairie, has not been surveyed 
since 1996, but recent habitat assessments show that it still contains 
prairie habitats with the native prairie flora conducive to the species 
(MN DNR 2013, unpubl.). Furthermore, the species expert in Minnesota 
supports that the species is most likely still present at these sites.
    We assigned a status of ``unknown'' if the species was found in 
1993 or more recently, but not in the most recent one to two sequential 
survey year(s) since 1993 and there is no evidence to suggest the 
species is now extirpated from the site (e.g., no destruction or 
obvious and significant degradation of the species' habitat). We 
considered a species to be ``possibly extirpated'' at sites where it 
was detected at least once prior to 1993, but not in the most recent 
one to two sequential survey years(s). A species is also considered 
``possibly extirpated'' at sites where it was found prior to 1993 and 
no surveys have been conducted in 1993 or more recently. At least three 
sequential years of negative surveys, no matter what years they were 
conducted, were necessary for us to consider the species ``extirpated'' 
from a site, because of the difficulty of detecting these species, as 
explained further in this section. A species is also considered 
``extirpated'' at sites where habitat for the species is no longer 
present. If the species is considered to be extirpated from a site, the 
occupancy status would not change unless the species is detected at 
that location during future surveys.
    When determining whether the species occupancy is unknown, possibly 
extirpated, or extirpated at a particular site, we used the survey year 
1993 as a cut-off date, because most known sites (more than 81 percent 
of known Poweshiek skipperling sites and more than 86 percent of known 
Dakota skipper sites) have been surveyed at least once since 1993, and 
survey data more than 20 years old may not reflect the current status 
of a species or its habitat at a site (for example, due to habitat loss 
from secondary succession of woody vegetation or a change in plant 
communities due to invasive species). Although it cannot be presumed 
that the species is absent at sites not surveyed since 1993, the 
likelihood of occupancy of these sites should be considered differently 
than sites with more recent survey data (e.g., due to woody vegetation 
succession over time). When analyzing survey results, we disregarded 
negative surveys conducted outside of the species' flight period 
(outside of June or July) or under unsuitable conditions (e.g., high 
wind speeds over approximately 16 miles-per-hour). We accepted survey 
data from those surveyors with whom we were confident in their ability 
to identify the species in the field.
    After we applied these standards to initially ascertain the status 
of the species, we asked species experts and Service personnel to help 
verify, modify, or correct species' occupancy at each site 
(particularly for sites with questionable habitat quality or those that 
have not been surveyed recently). In most cases, we used the status 
confirmed during expert review, unless we received additional 
information (e.g., additional survey or habitat data provided after the 
expert reviews) that suggests a different status at a particular site.
    Timing of surveys is based on initial field checks of nectar plant 
blooms and sightings of butterfly species with synchronous emergence 
(sightings of butterfly species that emerge at the same time as Dakota 
skipper and Poweshiek skipperling), and, more recently, emergence 
estimated by a degree-day emergence model using high and low daily 
temperature data from weather stations near the survey sites (Selby, 
undated, unpublished dissertation). Surveys are conducted during flight 
periods when the species' abundance is expected to be at levels at 
which the species can be detected. However, as with many rare species, 
detection probabilities are imperfect and some uncertainty remains 
between non-detection and true absence (Gross et al. 2007, pp. 192, 
197-198; Pellet 2008, pp. 155-156). Three sequential years of negative 
surveys is sufficient to capture variable detection probabilities, 
since each survey year typically encompasses more than one visit (e.g., 
the average number of visits per Dakota skipper site per year ranges 
from 1 to 11), and the probability of false absence after 5-6 visits 
drops below 5 percent for studied butterfly species with varying 
average detection probabilities (Pellet 2008, p. 159). Therefore, the 
site is considered ``extirpated'' if there are three sequential years 
of negative surveys (preferably, each year has more than one survey 
date).
    It cannot be presumed that the species is not persisting at a site 
only because there have not been recent surveys. At several sites, the 
species has persisted for longer than 20 years; for example, Dakota 
skipper was first recorded at Scarlet Fawn Prairie in South Dakota in 
1985 and has had positive detections (the species was detected during a 
survey) every survey since that date. The most recent detection was in 
2013. The year 1993 was chosen based on habitat-related inferences, 
specifically, the estimated time for prairie habitat to degrade to non-
habitat due to woody encroachment and invasive species. For example, 
native prairies with previous light-grazing management that were 
subsequently left idle transitioned from mixed grass to a mix of woody 
vegetation and mixed grass in 13 years and it was predicted that these 
idle prairies would be completely lost due to woody succession in a 30-
year timeframe (Penfound 1964, pp. 260-261). The time for succession of 
idle prairie depends on numerous factors, such as the size of the site, 
edge effects (the changes that occur on the boundary of two habitat 
types), and the plant composition of adjacent areas.
    This approach is the most objective way to evaluate the data range-
wide. Most sites have been surveyed over multiple years, although the 
frequency and type of surveys varied among sites and years. Surveys 
were conducted using various protocols (e.g., Pollard walks (Pollard 
1975), modified Pollard walks, wandering transects, timed transects) 
depending on the objective of the survey, funding or available 
resources, and staff. In several cases, species experts provided input 
on occupancy based on their familiarity

[[Page 63677]]

with the habitat quality and stressors to populations at particular 
sites.
    To summarize, there are few sites with relatively older data where 
we consider the species to still be present. In general, most Poweshiek 
skipperling sites with a present status have had a positive detection 
in 2008, or more recently with a few exceptions. At one Poweshiek 
skipperling site, the species was observed at the site in 1996, and no 
further surveys have been conducted. The remaining Poweshiek 
skipperling sites where the species is considered present have had 
detections in 2013, except four sites where the species was detected in 
2008, 2010, 2011, or 2012, and no further surveys have occurred. 
Likewise, in general, most Dakota skipper sites with a present status 
have had a positive detection in 2002, or more recently, with a few 
exceptions. At four Dakota skipper sites we consider the species to be 
present with the most recent record from 2001 or earlier including one 
site where the most recent survey was from 1994, and two sites with 
1996 records. No evidence suggests that the species is not still 
present at these sites because the best information indicates that the 
site's habitat is still conducive to the butterfly, and, therefore, the 
species may still be present there. We also consider Dakota skipper to 
be present at the following sites: 17 sites in Canada that were 
surveyed most recently in 2002; 1 additional site with a 2002 detection 
of the species and a favorable habitat assessment in 2012; 1 site with 
a 2003 detection; 1 site with a 2005 detection; 1 site with a 2006 
detection; 19 sites in Canada that were surveyed most recently in 2007; 
2 additional sites with a 2007 detection; 1 site with a positive 
detection in 2008; 3 sites with a positive detection in 2009; 23 sites 
with positive detections in 2012; and 10 sites with positive detections 
in 2013.

Population Distribution and Occupancy Status

    Once found in native prairies in five States and two Canadian 
provinces, the Dakota skipper and its habitat have undergone dramatic 
declines; the species is now limited to native prairie remnants in 
three States and two Canadian provinces. The Dakota skipper is presumed 
extirpated from Illinois and Iowa and no longer found in eastern 
Minnesota. Populations persist in a few locations in western Minnesota, 
northeastern South Dakota, North Dakota, southern Manitoba, and 
southeastern Saskatchewan. Royer and Marrone (1992a, p. 5) speculated 
that Dakota skippers may also occur in far eastern Montana and 
southeastern Saskatchewan, in habitats similar to those occupied by the 
species in northwestern North Dakota. The Dakota skipper was 
subsequently found in Saskatchewan in 2001 after 40 years of searching 
(Hooper 2002, pers. comm.), but no actual records have been found in 
Montana and Royer (2002, pers. comm.) no longer thinks that the species 
ever occured in Montana.
    From its earliest identification, the Dakota skipper was considered 
rare (Royer and Marrone 1992a, p. 1), although considerable destruction 
of its habitat likely occurred even before the species was first 
described in 1911. Habitat destruction and degradation has greatly 
fragmented Dakota skipper's range from its core through its northern 
and western fringes (McCabe 1981, p. 179; Royer and Marrone 1992a, p. 
28; Schlicht and Saunders 1994, p. 1; Royer 1997, p. 2; Schlicht 1997a, 
p. 2; Schlicht 1997b, p. 2; Skadsen 1997, pp. 25-26; Skadsen 1999c, p. 
15; Swengel and Swengel 1999, p. 267). The historical distribution of 
Dakota skippers may never be precisely known because ``much of 
tallgrass prairie was extirpated prior to extensive ecological study'' 
(Steinauer and Collins 1994, p. 42), such as butterfly surveys. 
Destruction of tallgrass and mixed-grass prairie began in 1830 (Samson 
and Knopf 1994, p. 418), but significant documentation of the 
ecosystem's butterfly fauna did not begin until about 1960. Therefore, 
most of the species' decline probably went unrecorded. Based on records 
of vouchered specimens, however, we know that Dakota skipper range has 
contracted northward out of Illinois and Iowa. The species was last 
recorded in Illinois in 1888 (McCabe 1981, p. 191) and in Iowa in 1992 
(Orwig and Schlicht 1999, p. 6). Britten and Glasford's (2002, pp. 363, 
372) genetic analyses support the presumption that this species 
formerly had a relatively continuous distribution; the small genetic 
divergence (genetic distance) among seven sites in Minnesota and South 
Dakota indicate that populations there were once connected. Dakota 
skipper dispersal is very limited due in part to its short adult life 
span and single annual flight. Therefore, the species' extirpation from 
a site is likely permanent unless it is within about 1 km (0.62 mi) of 
a site that generates a sufficient number of emigrants or is 
artificially reintroduced to a site.
    The Dakota skipper's range once comprised native prairie in five 
States and Canada, extending from Illinois to Saskatchewan; it now 
occurs only in native prairie remnants in portions of three States and 
two Canadian provinces. Of the 264 historically documented sites, there 
are 83 sites where we consider the Dakota skipper to be present, 88 
sites with unknown status, 41 possibly extirpated sites, and 52 that 
are considered extirpated (Table 1). Approximately 47 percent (39 of 
83) of the sites where the species is considered to be present are 
located in Canada, mostly within three isolated complexes, and were 
observed in 2002, or in 2007 with no subsequent surveys. Four 
additional locations where we consider the species to be present in 
Manitoba had positive detections of the species as recently as 2012 
(Rigney 2013a, p. 117). The remaining 42 sites where the species is 
considered to be present are about equally distributed among Minnesota 
(11 sites), North Dakota (16 sites), and South Dakota (14 sites). 
Researchers made positive detections of the species in 10 of these 
sites in 2013. The species was observed at 19 of these sites in 2012. 
Other U.S. sites with a present status with relatively older positive 
detections and no subsequent surveys for the species include one site 
with a positive detection in 1994, two sites with positive detections 
in 1996, one site with a positive detection in 2002, one site with a 
positive detection in 2005, one site with a positive detection in 2006, 
two sites with a positive detection in 2007, one site with a positive 
detection in 2008, and three sites with a positive detection in 2009. 
At several of these sites, the habitat has been assessed more recently 
than they were surveyed for the species. The distribution and status of 
Dakota skipper in each State of known historical or extant occurrence 
are described in detail below.

[[Page 63678]]



 Table 1--Number of Historically Documented Dakota Skipper Sites Within Each State and the Number of Sites Where
                the Species Is Thought To Be Present, Unknown, Possibly Extirpated, or Extirpated
----------------------------------------------------------------------------------------------------------------
                                      State's
                                     percentage
                                       of the
               State                   total       Present      Unknown      Possibly    Extirpated     Total
                                     number of                              extirpated
                                     historical
                                       sites
----------------------------------------------------------------------------------------------------------------
Illinois..........................          0.4  ...........  ...........  ...........            1            1
Iowa..............................          1.1                                                   3            3
Minnesota.........................         26.1           11           28           18           12           69
North Dakota......................         20.5           16           14           11           13           54
South Dakota......................         32.6           14           45           10           17           86
Manitoba..........................         14.0           28            1            2            6           37
Saskatchewan......................          5.3           14            0            0            0           14
                                   -----------------------------------------------------------------------------
Total Number of Historically        ...........           83           88           41           52          264
 Documented Sites.................
    Percent of the Total Number of  ...........           32           33           15           20  ...........
     Historical Sites by Occupancy
----------------------------------------------------------------------------------------------------------------

Illinois
    Dakota skippers are considered to be extirpated from Illinois. The 
species was last recorded near Chicago in 1888 (McCabe 1981, p. 191).
Iowa
    There are three historical records of Dakota skippers in three 
counties in Iowa (Dickinson, Poweshiek, and Woodbury), but the species 
is presumed extirpated from the State (Schlicht and Orwig 1998, pp. 84-
85; Selby 2004a, pp. 1, 5; Selby 2012, pers. comm.; Nekola and Schlicht 
2007, p. 9). The species was last seen at Cayler Prairie (Dickinson 
County) in 1992, but surveys of this site in 2000, 2004, 2005, and 2007 
were negative, so we presume it to be extirpated from that site 
(Schlicht and Orwig 1998, p. 85; Selby 2004a, p. 5; Selby 2006a, p. 5; 
Selby 2008, p. 6). The species was not observed at eight sites surveyed 
in the period 1988-1997 (Swengel and Swengel 1999, pp. 288-289), at 
eight sites surveyed in 2004 (Selby 2004a, p. 5), nor during extensive 
surveys at 32 sites in 2007 (Selby 2008, p. 6).
Minnesota
    Minnesota historically contained about 26 percent of the sites 
where the Dakota skipper has been recorded (Table 1) (Service 2014, 
unpubl. geodatabase). Since the earliest known record (1965) of the 
species in Minnesota, 66 sites have been recorded in the State, but 
recent surveys indicate that the species is declining in the State 
(Service 2014, unpubl. geodatabase). Of the 69 known locations of 
Dakota skipper in Minnesota; the species is extirpated or possibly 
extirpated from 30 of those sites, and the status is unknown at 28 
others (Service 2014, unpubl. geodatabase). The Dakota skipper is 
considered to be present at 11 sites in Minnesota in 3 counties: Clay, 
Lincoln, and Murray, although 2 of those sites have not been surveyed 
since 1996, and 1 site has not been surveyed since 1994.
    McCabe (1981, p. 187) observed very stable population numbers in 
Minnesota prairies that he visited repeatedly 1968-1979. On dry-mesic 
prairie in Lincoln County, Minnesota, Dana (Dana 1997, pp. 3-5) also 
observed stable numbers into the thousands during his intensive studies 
from 1978 to 1983. Schlicht (1997a, p. 13) and Reiser (1997, p. 16) 
reported more variable numbers on the same sites in 1995-1996, and 
based on these more recent observations, Dana (1997, pp. 3-5) suggested 
that populations could experience significant size fluctuations between 
years. At Hole-in-the-Mountain preserve, Minnesota, Dana (1991, pp. 36-
37) found peak abundance of approximately 1,000 Dakota skippers over 
about 40 ha (98 ac); he estimated that 2,000-3,000 individuals may have 
been alive at various times during the flight period and that only one-
third to one-half of adults were alive simultaneously. Where they 
occur, these high adult densities persist for only about a week to 10 
days during the single annual flight period (Selby and Glenn-Lewin 
1989, pp. 24-28).
    The percentage of sites surveyed each year in Minnesota with 
positive detections remained relatively stable from 1985 to 2005, with 
an average detection rate of 67 percent for all survey years with more 
than one site surveyed (excluding sites newly discovered in the first 
year it was discovered), an average of 70 percent detection rate for 
survey years with 5 or more sites surveyed and an average of 66 percent 
detection rate for survey years with 10 or more sites surveyed. One 
exception to the high detection rates was 1994; only 26 percent (5 of 
19 sites) of sites surveyed in 1994 resulted in positive detections. 
Recent surveys of the species resulted in significantly lower than 
average positive detections. The percent of sites surveyed each year 
with positive detections has recently decreased from 70 percent (7 of 
10 sites) in 2005, to 47 percent (8 of 17 sites) in 2007, 56 percent 
(10 of 18 sites) in 2008, 6 percent (1 of 16 sites) in 2012, and to 7 
percent (1 of 15 sites) in 2013 (for years with greater than 10 sites 
surveyed, see Figure 1). Only one individual was detected in Minnesota 
during 2012 surveys, which included 18 sites with previous records and 
23 prairie remnants without previous records for the species (Dana 
2012c, pers. comm.; Runquist 2012a, pers. comm.; Olsen 2012, pers. 
comm.). Dakota skippers were detected at 1 site in Minnesota during 
2013 surveys, which included 15 sites with previous records and 12 
prairie remnants without previous records for the species (Runquist 
2014, pp. 3-6; Selby 2014, pp. 2-5; Rigney 2013b, p. Appendix B; 
Service 2014, unpubl. geodatabase.). The cause for this sharp decline 
is unknown.

[[Page 63679]]

[GRAPHIC] [TIFF OMITTED] TR24OC14.009

    The Dakota skipper is presumed extirpated at 12 sites in Minnesota; 
at 7 of these sites the species has not been observed since 1984 or 
earlier. Four sites at which the species is now presumed to be 
extirpated have had fairly recent positive observations. The species 
was last observed at Prairie Waterfowl Production Area (WPA) in Big 
Stone County in 2000 (Skadsen 2000, p. 1), for example, but was not 
found in 2008 (Selby 2009a, p. i), 2010, and 2012 (Service 2014, 
unpubl. geodatabase). Dakota skippers were observed at the Glacial 
Lakes WPA in 2001 (Schlicht 2001b, p. 18), but the species was not 
observed in 2003, 2004, and 2005 (Selby 2006b, p. Appendix A xii); the 
species is now considered to be extirpated at that site (Service 2014, 
unpubl. geodatabase). The last observation of Dakota skipper at the Big 
Stone National Wildlife Refuge (NWR) in Lac Qui Parle County was in 
2000, and it was not observed during surveys in 2009, 2011, or 2012 
(Skadsen 2012a, p. 5). Dakota skippers were observed at Chippewa 
Prairie in 1995, but not in 1996, 2005, and 2012 (Service 2014, unpubl. 
geodatabase). Of the 18 sites where the species is possibly extirpated, 
4 have not been surveyed since the species was last seen in 1989 or 
earlier. Dakota skippers at two of the sites where the species is 
possibly extirpated have not been observed since 1991 (Service 2014, 
unpubl. geodatabase). One site, with a positive detection in 1998, was 
ranked as ``possibly extirpated'' based on expert opinion. The 
remaining 11 sites had positive observations prior to 1993, were 
surveyed once more recently, and had a negative observation (Service 
2014, unpubl. geodatabase).
    The status of the Dakota skipper is unknown at 28 sites; Dakota 
skipper have not been observed at 14 of these sites since the mid- to 
late 1990s, despite one or two years of survey effort at several sites. 
The remaining 14 sites with unknown status have had positive 
observations in 2007 or more recently, but are given this designation 
due to one or two subsequent negative surveys. For example, Dakota 
skipper was documented at the Gens Prairie in Murray County and 
Woodstock Prairie in Pipestone County in 2007, but the species was not 
observed during surveys in 2008 or 2013 (Selby 2009a, p. Appendix 5 li, 
xxxiii and Appendix 4 xlix; Selby 2014, p. 5).
    In 2007 and 2008, the Minnesota DNR carried out a broad survey 
effort to assess the status of Dakota skipper and other prairie 
butterflies in the State after experts noted significant declines in 
these species in west-central Minnesota beginning in 2003 (Selby 2006b, 
p. 30). Researchers surveyed 17 and 19 sites with previous Dakota 
skipper records in 2007 and 2008, respectively; Dakota skipper was 
found at 8 sites each year and at 1 site where it had not previously 
been recorded (Selby 2009a, p. 6). The surveys confirmed Dakota 
skipper's extirpation from one site in Cottonwood County, where it was 
last recorded in 1970.
    A parallel study in 2007 (Dana 2008) consisted of more intensive 
work at a few sites thought to contain some of the State's most viable 
populations of Dakota skipper. Among these sites was The Nature 
Conservancy's Hole-in-the-Mountain preserve in Lincoln County, which 
was the only Minnesota population rated as secure in 2002 (Cochrane and 
Delphey 2002, p. 16). The 2007 surveys indicated that the site still 
supported a substantial population, but that it may have decreased in 
size since earlier studies were conducted (Dana 1991, p. 36; Dana 2008, 
p. 18). Dakota skippers were not detected during the 2012 or 2013 
flight periods (Runquist 2012, pp. 13-14, 18-20; Runquist 2012a, pers. 
comm., Selby 2014, p. 5); therefore, we consider the status of the 
species at the Hole-in-the-Mountain preserve to be unknown.

[[Page 63680]]

    Relatively important populations of Dakota skipper in Minnesota may 
still occur at the Prairie Coteau, Felton Prairie, and Glacial Lakes 
complexes, but the 2012 and 2013 survey results raised concern for the 
species' status at Prairie Coteau. The number of Dakota skippers 
encountered per 100 m (328 ft) of transect at Prairie Coteau State 
Natural Area (SNA) were 1.7 in 1990 and 1.1 in 2007 (Dana 2008, p. 19). 
No Dakota skippers were observed at Prairie Coteau SNA during the 2012 
or 2013 flight periods (Runquist 2012, pp. 9-10); therefore, we 
consider the status of the species to be unknown at that site. Selby 
(2009b, Appendix 4, p. iv) recorded 14 Dakota skippers during a 5-hour 
survey in 2007 at the Felton Prairie SNA. During a 1-hour survey in 
2008, nine Dakota skippers were recorded and with little indication of 
any substantial change since the previous year (Selby 2009b, Appendix 
5, p. iv); Felton Prairie was resurveyed in 2013, and no Dakota 
skippers were observed (Service 2014, unpubl. geodatabase). The number 
of Dakota skippers recorded during recent surveys at Glacial Lakes 
State Park has been low despite good habitat conditions. An apparently 
widespread population was present as recently as 2001 when Skadsen 
(2001, p. 24) found Dakota skippers along almost all of 40 km (25 mi) 
of transect in and around the park--he recorded as many as 31 Dakota 
skippers along one transect (Skadsen 2001, p. 24). Selby (2009a, p. 1 
and 1iv) surveyed the same areas in 2007 and 2008, describing habitat 
at survey sites as good to excellent, but recorded only eight Dakota 
skippers during about 7 hours of surveys in and around the park (Selby 
2009a, p. 1 and 1iv). Glacial Lakes State Park surveys conducted in 
2012 were outside of the Dakota skipper flight period (Runquist 2012a, 
pers. comm.), and the species was not detected in 2013 (Selby 2014, p. 
5).
    In summary, the Dakota skipper is now considered to be extirpated 
or possibly extirpated from at least 30 of the 69 sites in Minnesota, 
which historically contained approximately 26 percent of all known 
historical Dakota skipper locations rangewide (Table 1). The species is 
considered to be present and unknown at 12 and 27 sites, respectively. 
However, only one individual male was detected in the State during 2012 
surveys, which included 18 sites with previous records; 2012 surveys 
for undiscovered populations were also carried out on 23 prairie 
remnants without previous records for the species. Only 6 individual 
Dakota skipper were observed in 2013 surveys in Minnesota, which 
included 15 sites with previous records; 2013 surveys for undiscovered 
populations were also carried out on 12 prairie remnants without 
previous records for the species (Service 2014, unpubl. geodatabase). 
Similar surveys of prairie remnants with no previous documentation of 
Dakota skipper were completed in Minnesota in 2007 and 2008. Based on 
these surveys, the likelihood that significant undiscovered Dakota 
skipper populations occur in Minnesota is low.
North Dakota
    North Dakota historically contained approximately 21 percent of all 
known historical locations of Dakota skippers rangewide (Table 1); the 
State contained 54 historical sites distributed among 18 counties 
(Service 2014, unpubl. geodatabase). The Dakota skipper is currently 
present at 16 sites in 5 North Dakota counties, of these, 11 occur 
within the Towner-Karlsruhe complex in McHenry County, 1 is within the 
Sheyenne National Grasslands complex in Ransom County, 2 are in 
northern McKenzie County, and 1 site is in Wells County. Of the 16 
sites where we consider the Dakota skipper to be present, 15 sites had 
positive observations of the species in 2012. The remaining site had 
positive observations in 2002. The status of the species is unknown at 
14 sites; 10 of these sites have not had positive records since the 
mid- to late 1990s, and the other 4 sites had positive records between 
2001 and 2003. The Dakota skipper is presumed extirpated from 13 sites 
and 4 counties, primarily due to heavy grazing, weed control, and other 
disturbances (e.g., bulldozing at Killdeer Mountain to reduce aspen 
growth, Royer 1997). The species is possibly extirpated from 11 
additional sites and 3 additional counties.
    Researchers surveyed 25 sites, believed to possibly have Dakota 
skipper populations, in 2012; of these sites, 23 had previous records 
of the species (Royer and Royer 2012a, entire). Thirteen of the 25 
surveyed sites had Dakota skipper present (Royer and Royer 2012a, pp. 
3-4; Royer and Royer 2012b, pp. 2-3). One new site was found in 2012 
(Royer and Royer 2012a, p. 33), adjacent to a site with previous 
records but with different land-ownership, so the researcher considered 
it a new site. Another new site was found in North Dakota in 2012, in 
Wells County, where two observations were made--possibly the same 
individual (HDR, Inc. 2012, pp. 21-23). At sites with Dakota skipper, 
lower average encounter frequencies were observed across the State in 
2012 (State average = 9.4 encounters per hour) than during the 1996-
1997 statewide surveys (State average = 17.4 encounters per hour) 
(Royer and Royer 2012b, p. 5; Royer and Royer 2012a. pp. 7-8). Three 
sites with previous Dakota skipper records in North Dakota were 
surveyed during the 2013 flight period; the species was not detected in 
any of those surveys (Fauske 2013 data (in ND National Guard 2013, in 
litt.; HDR Engineering 2013, pp. 10-11).
    Of the Dakota skipper populations in North Dakota, none may be 
secure, although the Towner-Karlsruhe complex was considered to be the 
stronghold for the species in the State in 2002 (Cochrane and Delphey 
2002, p. 17), and most of the sites where the species is currently 
present are still occupied by ``viable populations'' (Royer 2012a, 
pers. comm.). All of the habitat where the species is present in the 
Towner-Karlsruhe complex is Type A (wet-mesic) habitat (Royer and 
Marrone 1992a, pp. 21-22; Royer et al. 2008, pp. 14-16). Three sites 
within the Towner-Karlsruhe complex are owned by the North Dakota State 
Land Department, and the remaining nine sites with extant populations 
are privately owned. Some Towner-Karlsruhe sites are linked by highway 
rights-of-way that contain native prairie vegetation and by other 
prairie remnants (Royer and Royer 2012a, p. 18). In 2002, none of these 
sites were described as secure (Cochrane and Delphey 2002, pp. 66-67) 
since each is subject to private or State management options that could 
extirpate Dakota skipper from the site. In 1999, it was estimated that 
about 30 percent of the Towner-Karlsruhe area still contained native 
prairie (Lenz 1999, p. 2); more recent observations indicate that 
several native prairie sites have been invaded to varying extents by 
nonnative species, such as leafy spurge, Kentucky bluegrass, and 
alfalfa (Medicago sativa), and several are subject to intense grazing 
or early haying (Royer and Royer 2012b, pp. 5-6, 7-10, 13-16, 18-19, 
22-23; Royer 2012, in litt.).
    Dakota skipper populations in the Sheyenne National Grasslands 
complex have experienced intensive grazing, leafy spurge (Euphorbia 
esula) invasion, and the effects of herbicides used to control leafy 
spurge and grasshoppers (Royer 1997, pp. 15 and 27). For example, 
McCabe (1979, p. 36) cited the McLeod Prairie in the Sheyenne 
Grasslands in southeastern North Dakota as the best site for Dakota 
skippers in North Dakota. Since then, however, leafy spurge invasion 
has significantly modified the habitat, and the Dakota skipper is now 
extirpated

[[Page 63681]]

from the site (Royer 1997, p. 14). Swengel and Swengel (1999, p. 286) 
did not find Dakota skippers at eight survey sites in the Sheyenne 
grasslands during 1988-1997, although Royer did observe a few isolated 
Dakota skippers in the Sheyenne National Grasslands during this period 
(e.g., Royer 1997, pp. 14-15). Dakota skippers were recorded at one new 
site (Gregor) in the Sheyenne National Grasslands in 2001 (Spomer 2004, 
pp. 14-15). The status of Dakota skipper at the Gregor site is 
currently unknown, since the species was not observed during the 2002 
survey (Royer and Royer 2012a, pp. 3-4).
    Orwig (1996, p. 3) suggested that Brown's Ranch in Ransom County, 
owned by The Nature Conservancy, had potential to support a 
metapopulation (groups of local populations interconnected by dispersal 
habitat) in the Sheyenne River watershed. More recently, however, 
Spomer (2004, p. 36) found that the population there was not doing 
well, and Royer failed to find the species in 2012 (Royer and Royer 
2012a, p. 3). Therefore, the status of the species at the Brown Ranch 
site is unknown. Royer (1997, pp. 15 and 27) claimed that, throughout 
the Sheyenne Grasslands, both public and private lands have been so 
heavily grazed and altered by grasshopper and leafy spurge control that 
extirpation of Dakota skippers from the area is almost certain to 
occur. The population at Venlo Prairie, for example, deteriorated from 
good/fair in 2001 to poor in 2003 due to intense grazing and 
disappearance of flowers (Spomer 2004, pp. 9, 12); the species is now 
considered to be extirpated at that site. The population at Garrison 
Training Area in McLean County is now considered unknown due to 
negative surveys in 2004 and 2013 (Fauske 2004, p. 1; Fauske 2013 in ND 
National Guard 2013, in litt.).
    In 2002, experts ranked all sites outside of the two complexes 
discussed above as threatened or vulnerable; most were small and 
isolated populations threatened by conversion and invasive species 
(Cochrane and Delphey 2002, pp. 66-67). Most of these sites are now 
considered extirpated or possibly extirpated. Today, only 3 sites 
outside of the Towner-Karsruhe Complex and Sheyenne National Grasslands 
complexes are thought to have extant (present) Dakota skipper 
populations. In addition to the Towner-Karsruhe Habitat Complex sites 
in McHenry County, only 2 of the 25 sites surveyed by Royer in 2012, 
both in northern McKenzie County, may have ``viable populations'' 
(Royer 2012b, pers. comm.), although only one individual was observed 
at each site in 2012 (Royer and Royer 2012b, pp. 16-17). Only three 
sites with previous records were surveyed in North Dakota during the 
2013 flight period, and the Dakota skipper was not observed (Fauske 
2013 in ND National Guard 2013, in litt.; HDR Engineering 2013, pp. 10-
11).
    In summary, North Dakota contains approximately 21 percent (N = 54) 
of all known historical locations of the species rangewide; however, 
the current occupancy status of the Dakota skipper is unknown at 14 
sites, and it is considered to be extirpated or possibly extirpated 
from at least 24 of the 54 known sites in the State (Table 1). The 
species is considered to be present at 16 sites in the State. North-
central North Dakota may hold hope for the species' long-term 
conservation. Dakota skipper was detected at 13 of the 25 sites 
surveyed during 2012 (23 of the sites had previous Dakota skipper 
records); average encounter frequencies observed across the State in 
2012 (9.4 encounters per hour), however, were lower than during the 
1996-1997 State-wide surveys (ND State average = 17.4 encounters per 
hour) using the same methodology. The species was not detected at the 
three sites surveyed in 2013.
    Although only a small fraction of all grassland in North Dakota has 
been surveyed for Dakota skippers, a significant proportion of the un-
surveyed area is likely not suitable for Dakota skipper. The species 
was never detected at approximately 108 additional locations in North 
Dakota that were surveyed for the species in the period 1991-2013 
(USFWS 2014, unpubl. geodatabase). Many of these sites have been 
surveyed multiple times over multiple years (USFWS 2014, unpubl. 
geodatabase). Surveys for the Dakota skipper are typically conducted 
only in areas where floristic characteristics are indicative of their 
presence. New potential sites surveyed are generally focused on prairie 
habitat that appears suitable for the species and has a good potential 
of hosting the species, in other words, sites are not randomly selected 
across the landscape. Therefore, researchers have a higher likelihood 
of detecting the species at these sites than at sites randomly selected 
across the landscape. Based on these surveys, the likelihood that 
significant numbers of undiscovered Dakota skipper populations occur in 
North Dakota is low. Moreover, data available from the numerous sites 
that have been surveyed are likely to be representative of areas that 
have not been surveyed--that is, population trends and the nature and 
extent of stressors that may impact the populations in un-surveyed 
areas can reasonably be inferred by analyzing data collected from the 
sites that have been surveyed.
South Dakota
    South Dakota historically contained approximately 33 percent of all 
known locations of Dakota skippers rangewide (Table 1). Since the 
earliest known record of Dakota skipper (1905) in South Dakota, 86 
sites have been documented across 11 counties in the State, but recent 
surveys indicate that the species is declining in the State (Service 
2014, unpubl. geodatabase). Of the 86 historical sites, Dakota skipper 
is presumed extirpated from 17 sites and 2 counties (Brown and Moody), 
and is possibly extirpated from 10 additional sites. Dakota skipper is 
considered present at 14 sites, and the status of the species is 
unknown at 45 sites. Twenty-seven sites in South Dakota with previous 
Dakota skipper records were surveyed in 2012; the species was detected 
at 9 of those sites (Service 2014, unpubl. geodatabase). Eight 
additional sites within the species' historical range were surveyed 
during the 2012 flight period, which resulted in the discovery of two 
new nearby Dakota skipper sites (Service 2014, unpubl. geodatabase; 
Skadsen 2012a, pers. comm.). Twenty-eight sites in South Dakota with 
previous Dakota skipper records were surveyed in 2013; the species was 
detected at 9 of those sites (Service 2014, unpubl. geodatabase). Ten 
additional sites within the species' historical range were surveyed 
during the 2013 flight period, which resulted in no new Dakota skipper 
sites discovered (Service 2014, unpubl. geodatabase). The proportion of 
positive surveys at known sites has fluctuated over time; however, the 
2012 and 2013 surveys had the lowest positive detection rate (35 
percent and 32 percent, respectively) for the last 16 years (since 
1996), much less than comparable survey years (years with 10 or more 
sites surveyed) in South Dakota.
    While there are some sites with earlier records, most South Dakota 
sites were initially documented during extensive surveys conducted 
during 1996 to 1998. Forty-eight locations without previous records 
were surveyed during 2002-2004, which resulted in the discovery of 20 
new Dakota skipper sites in northeastern South Dakota (Skadsen 2003, p. 
8; Skadsen 2004, pp. 3-6), but due to more recent negative surveys, the 
occupancy of the species is currently unknown or extirpated at many of 
these sites (Skadsen 2011, p. 5; Skadsen 2012b, pp. 4-5; Skadsen, 2012, 
pers. comm.; Skadsen 2003, p. 10; Skadsen

[[Page 63682]]

2004, p. 2; Skadsen 2006a, p. 2, 10; Skadsen 2006b, p. 5; Skadsen 2007, 
p. 3; Skadsen 2008, p. 3, 12; Skadsen 2009, p. 3). Additional survey 
effort resulted in the discovery of nine new sites between 2005 and 
2012, with a maximum of three new sites discovered in 2006 (Skadsen 
2010a, p. 6; Skadsen 2012b, pp. 4-5; Skadsen 2012, pers. comm.; Skadsen 
2005, pp. 5-6, Skadsen 2006a, p. 12; Skadsen 2006b, p. 5; Skadsen 2007, 
p. 3; Skadsen 2008, p. 9; Skadsen 2009, p. 2). Eight additional sites 
without previous documentation of the species were surveyed in 2012, 
which resulted in the discovery of two nearby sites (Service 2014, 
unpubl. geodatabase). To summarize, new sites have been discovered in 
South Dakota during most survey years since 2002, however, the number 
of new sites discovered each year has been low recently; two or three 
new sites have been discovered each survey year since 2005 (three sites 
in 2005, two sites in 2006, two sites in 2007, zero sites in 2010, two 
sites in 2012, and zero sites in 2013). The rate that known sites are 
becoming extirpated is higher than the rate of new discovery--the 
occupancy of the species at many sites is now unknown or extirpated due 
to more recent negative surveys.
    The species has never been documented in Clark County, but because 
few surveys have been conducted there, the county may contain 
undiscovered populations (Skadsen 2006b, p. 1). Skadsen (2012b, pers. 
comm.) doubts the existence of public lands with suitable Dakota 
skipper habitat in Clark County and has not received permission to 
survey a few possible suitable locations that are privately owned.
    Although only a small fraction of all grassland in eastern South 
Dakota has been surveyed for Dakota skippers (e.g., Dakota skipper 
surveys have been conducted on less than approximately 30,000 acres 
(12,140 ha) in South Dakota within the species range (Service 2014, 
unpubl. geodatabase)), a significant proportion of the un-surveyed area 
may not be suitable for the Dakota skipper, based on surveys in 
additional areas of possible habitat where the species was not detected 
. For example, there is an estimated 1,620,549 acres (ac) (655,813 
hectares (ha)) of unbroken (untilled) grasslands that may provide 
habitat for the Dakota skipper in the nine counties where the Dakota 
skipper is considered be present or to have unknown occupancy in South 
Dakota (HAPET 2012, unpubl. data). Additional areas of unbroken prairie 
were estimated in three other counties where the species may have 
occurred historically (HAPET 2012, unpubl. data). While these lands 
represent unbroken grassland in South Dakota, the models used to 
identify unbroken grassland are not able to identify plant species, 
plant species composition, floristic quality, or presence of invasive 
species (Loesch 2013, pers. comm.). Therefore, it is not known if these 
unbroken grasslands contain the specific native prairie plants that the 
Dakota skipper requires (as discussed in detail in the Background 
section of this proposed rule) and, therefore, may not equate to 
suitable habitat for the species.
    The species was never detected at approximately 79 additional 
locations in South Dakota that were surveyed from 1991 through 2013 
(USFWS 2014, unpubl. geodatabase). Several of these sites have been 
surveyed multiple times in one year or during multiple years (USFWS 
2014, unpubl. geodatabase). Surveys for Dakota skipper are typically 
conducted only in areas where floristic characteristics are indicative 
of their presence. For example, in South Dakota, Skadsen (1997, p. 2) 
selected for surveys dry-mesic prairie that supported purple coneflower 
and wet-mesic prairie that supported wood lily and mountain deathcamas 
based on searches for these sites by car and reports from resource 
managers. Only sites with landowner permission are accessed for 
surveys, however, new potential sites surveyed are generally focused on 
prairie habitat that appears suitable for the species and has a good 
potential of hosting the species, in other words, sites are not 
randomly selected across the landscape. Therefore, researchers have a 
higher likelihood of detecting the species at these sites than at sites 
randomly selected across the landscape. Based on these surveys, the 
likelihood that significant undiscovered Dakota skipper populations 
occur in South Dakota is low. Moreover, data available from the 
numerous sites that have been surveyed are likely to be representative 
of areas that have not been surveyed--that is, population trends and 
the nature and extent of stressors that may impact the populations in 
un-surveyed areas can reasonably be inferred by analyzing data 
collected from the sites that have been surveyed.
    Since there is little long-term quantitative data for sites in 
South Dakota, we examined presence-absence (non-detection) data over 
time. The percent of sites surveyed each year with positive detections 
of the species remained relatively stable from 1985 to 2010, with an 
average positive detection rate of 63 percent for all survey years with 
more than one site surveyed (excluding new sites for the first year of 
discovery), an average positive detection rate of 60 percent for survey 
years with at least 5 sites surveyed, and an average positive detection 
rate of 71 percent for survey years with at least 10 sites surveyed. 
One exception to the high detection rates was during the 1991 survey 
year when none (0 of 7 sites) of the sites surveyed in 1991 resulted in 
positive detections of the species, excluding 3 new sites that were 
discovered that year. Another exception was in 1996, when 2 of the 8 
sites with previous records surveyed had a positive detection; however, 
6 new sites were discovered that year. The detection rate remained 
relatively stable until 2010, when the percent of sites with positive 
detections fell from 89 percent (8 of 9 sites) in 2010, to 46 percent 
(5 of 11 sites) in 2011, 35 percent (9 of 26 sites) in 2012, and 32 
percent (9 of 28 sites) in 2013 (Figure 2). These types of fluctuations 
had been observed in prior years; therefore, it is difficult to 
determine a clear trend in the data using positive detections--the last 
two survey years may fall within the normal range of variation.

[[Page 63683]]

[GRAPHIC] [TIFF OMITTED] TR24OC14.010

    The Outer Coteau des Prairies subsection of the North Central 
Glaciated Plains section of Bailey's Eco-regions is thought to be a 
stronghold for Dakota skipper, since nearly 34 percent of the total 
documented Dakota skipper sites are within that subsection (89 of the 
264 documented sites--Service 2014, unpubl. geodatabase). Most of these 
Outer Coteau des Prairie sites are in South Dakota; 73 of the 86 Dakota 
skipper sites in South Dakota are within the Outer Coteau des Prairies 
subsection (Service 2014, unpubl. geodatabase). Dakota skipper is 
considered to be present at only 9 of those 73 sites--the species 
status is unknown at 40 of those sites, possibly extirpated at 8 sites, 
and extirpated at the remaining 16 sites within that ecoregion 
subsection in South Dakota (Service 2014, unpubl. geodatabase).
    In summary, South Dakota historically contained approximately 33 
percent of all known locations of the species rangewide. The current 
occupancy status of the Dakota skipper is unknown at 45 sites, and it 
is considered to be extirpated or possibly extirpated from at least 27 
of the 86 known sites in the State, although large areas of grasslands 
remain in South Dakota we don't expect significant additional 
populations to be found if more surveys were conducted. Furthermore, 
downward trends and threats impacting populations at known sites are 
also likely occurring at potentially undiscovered sites. The species is 
considered to be present at 14 of the 86 documented sites in the State. 
Twenty-six sites in South Dakota with previous Dakota skipper records 
were surveyed in 2012; the species was detected at nine of those sites; 
eight sites with no previous records for the species were surveyed 
during the 2012 flight period, which resulted in the discovery of two 
nearby sites. Twenty-eight sites in South Dakota with previous Dakota 
skipper records were surveyed in 2013; the species was detected at 9 of 
those sites (Service 2014, unpubl. geodatabase). Ten additional sites 
within the species' historical range were surveyed during the 2013 
flight period, which resulted in no new Dakota skipper sites discovered 
(Service 2014, unpubl. geodatabase). The proportion of positive surveys 
at known sites has fluctuated over time; however, the 2012 and 2013 
surveys had the lowest positive detection rate (35 percent and 32 
percent, respectively) for the last 16 years (since 1996)--much less 
than comparable survey years in South Dakota.
Manitoba
    Manitoba historically contained approximately 14 percent (N = 37) 
of the known locations of the Dakota skipper rangewide. The Dakota 
skipper is considered present at 1 isolated site and 28 sites split 
between 2 distinct complexes, 12 sites near Griswold and 16 sites along 
Lake Manitoba. The 12 sites near Griswold are located approximately 200 
km (124 mi) southwest of the populations along Lake Manitoba (at 16 
sites) and about 125 km (78 mi) northeast of the nearest population in 
Saskatchewan (Webster 2003, pp. 5-6; Webster 2007, p. 4). The species 
is considered to be unknown at one site near Griswold where the species 
was detected in 2007 and 2011, but not during the most recent survey 
year (2012) (Rigney 2013a, p.117). The species is presumed extirpated 
or possibly extirpated from eight sites in Manitoba, including from the 
Tallgrass Prairie Preserve, where it has not been

[[Page 63684]]

found in the seven most recent survey years (Webster 2003, p. 5; 
Westwood et al. 2012, p. 1; Westwood 2007, pers. comm.; Hamel et al. 
2013, pp. 8-16)--(the later surveys were focused on Poweshiek 
skipperlings, but other species were recorded), and one site that was 
converted to a flaxseed field (Webster 2003, p. 7).
    In 2007, researchers surveyed 16 sites for the Dakota skipper near 
Griswold, Manitoba (Webster 2007, p. 4), and found Dakota skippers at 
14 of the 16 sites; 12 of these represent new sites for the species in 
Manitoba (Webster 2007, p. 4). Four of these sites were resurveyed in 
subsequent years (2010, 2011, and 2012)--the species is considered to 
be present at two sites, is unknown at one site due to a recent 
negative survey, and extirpated at the fourth site due to 3 consecutive 
negative survey years (Rigney 2013a, p. 117; Service 2014 unpublished 
database). The species is considered to be present at the remaining 10 
sites that have not been surveyed since 2007.
    Until recently, population estimates and trends at the sites near 
Griswold in south west Manitoba have not been examined quantitatively; 
however, the population appears to be relatively stable at one site, 
may be declining at a second site, and is considered extirpated from 
two sites with repeated survey years. Numbers observed during searches 
at a site near Griswold in 2007 did not appear to change appreciably 
since 2002 surveys, when the population was estimated (non-
quantitatively) to be approximately 750 individuals (Webster 2003, p. 
5; Webster 2007, p. 4). A total of 273 adults were observed during a 
3.3-hour survey at the second site, where the population was estimated 
non-quantitatively to be about 2,000 individuals (Webster 2007, p. 4). 
Survey methodology changes in the years since 2007 (two to five surveys 
per site per flight period in the timeframe 2009-2013 compared to 
single site visits per year prior to 2008) have provided more rigorous 
population estimates at four Manitoba sites near Griswold and have 
shown a marked reduction in densities since 2002 or 2007 at three of 
the four sites (Rigney 2013a, p. 117). The Dakota skipper is present at 
two of the four sites near Griswold with repeated survey years. The 
estimated densities (mean number of individuals observed per hour) at 
one site remained at 1/hour in 2011 and 2012 and was approximately 30/
hour in 2011 and 33/hour in 2012 at a second site. The species is 
considered extirpated at one of these sites, because it was not 
detected during 2010, 2011, and 2012 surveys. The status of the species 
is unknown at another site where the estimated numbers fell from 2/hour 
to zero detected in 2012 (Rigney 2013a, p. 117).
    The Dakota skipper was first recorded near Winnipeg in 1933 and 
near Miniota in 1944 and then at two additional sites in the early 
1990s. The species is considered to be extirpated or possibly 
extirpated at all of these sites (Service 2014 unpubl. geodatabase).
    In 2002, the species was observed at 19 sites near Lundar, within 
about 25 km (16 mi) east of Lake Manitoba (Interlake region) (Webster 
2003, p. 4); however, most of these sites have not been surveyed since. 
Similar to the Griswold sites, the survey methodology changes in years 
since 2007 (two to five surveys per site per flight period during 2009-
2013 compared to single site visits per year prior to 2008) have 
provided more rigorous population estimates at four Manitoba sites near 
Lake Manitoba (Interlake region) and have shown a marked reduction in 
densities since 2002 or 2007 at two of the four sites (Rigney 2013a, p. 
117). The species is considered present at two of four sites that have 
been surveyed since 2002 in this area; the species is considered 
extirpated from the other two sites due to three consecutive negative 
survey years (2010, 2011, and 2012) (Rigney 2013a, p. 117). The mean 
number of individuals observed per hour at one site has declined from 
2/hour in 2011 to 1/hour in 2012 (Rigney 2013a, p. 117). The mean 
number per hour increased from approximately 1/hour to 6/hour at 
another site (Rigney 2013a, p. 117). The species is considered to be 
present at the remaining 14 Interlake sites that have not been 
resurveyed since 2002 (Service 2014, unpublished database).
    Several additional areas were examined for potential Dakota skipper 
habitat in 2007, including areas east of Hwy 21, within the Lauder 
Sandhills Wildlife Management Area, north of Oak Lake and near Tilston, 
Sinclair, Cromer, and Brandon, as well as other locations. Most of the 
areas examined were under row crop agriculture, were heavily grazed, 
were dry scrub prairies, or were otherwise habitats unsuitable for 
Dakota skipper (Webster 2007, p. 6). In 2007, the areas near Brandon 
and the high ground within the wetland complexes near Oak Lake still 
contained potentially suitable habitat (Webster 2007, p. 6).
    The nearest known extant (present) population of Dakota skippers in 
Manitoba is approximately 120 km (75 mi) from the closest extant 
(present) population in North Dakota and about 111 km (69 mi) from the 
closest Saskatchewan population. Britten and Glasford (2002, pp. 367, 
372) suggested that Manitoba populations are genetically distinct from 
a group of populations in Minnesota and South Dakota, although 
populations in additional intervening locations should be sampled to 
confirm this hypothesis (Runquist 2012b, pers. comm.).
Saskatchewan
    Saskatchewan historically contained approximately 5 percent (N=14) 
of all known records of Dakota skippers rangewide. In Saskatchewan, the 
Dakota skipper is restricted to undisturbed or lightly grazed, steep, 
south-facing hills near the Souris River (Webster 2007, p. ii). The 
Dakota skipper was first recorded south of Oxbow, Saskatchewan, in 2001 
where three males were collected (Hooper 2003, p. 124) on an ungrazed 
knoll within a patch of mixed-grass prairie that was approximately 1 ha 
(2 ac) in extent. Dakota skippers were found at three additional sites 
during 2002 surveys (Webster 2003, pp. 6-7). In 2007, researchers 
surveyed 16 sites in southeastern Saskatchewan and found Dakota 
skippers at 10 of these sites (including Oxbow); 8 of these represent 
new sites for the species in Saskatchewan (Webster 2007, p. i). During 
2007 surveys, which were conducted late in the flight period, only a 
few individuals were observed at each site where the species was 
present (Webster 2007, p. ii). Nine of these sites where the species 
was found in 2007 were surveyed along an approximate 50-km (31-mi) 
stretch of steep hillsides along the ridgeline north of Souris River; 
distances between sites range from 1 to 28 km (0.8 mi to 17 mi). We 
consider Dakota skipper to be present at all 14 sites in Saskatchewan, 
although 3 of those sites have not been surveyed since 2002. The 
nearest known extant population of Dakota skippers in Saskatchewan is 
approximately 111 km (69 mi) from the closest extant (present) 
population in North Dakota and 200 km (125 mi) from the closest 
Manitoba population.

Poweshiek Skipperling

Species Description

    The Poweshiek skipperling (Oarisma poweshiek) is a member of the 
skipper family, Hesperiidae, and was first described by Parker (1870, 
pp. 271-272). Parker (1870, pp. 271-272) provided the original 
description of this species from his type series collected near 
Grinnell, Iowa. It was named for the county in which it was found 
(Poweshiek County), but it was misspelled, Powesheik, in the original

[[Page 63685]]

description. This spelling was retained by most early authorities 
(Lindsey 1922, p. 61; Holland 1931, p. 360). Miller and Brown (1981, p. 
31) used the corrected spelling, Poweshiek, but then Miller and Ferris 
(1989, p. 31) changed it back in their supplement. Current usage is 
mixed, with many authorities retaining the original spelling (e.g., 
Miller 1992, p. 20), while others have opted for the corrected spelling 
(Layberry et al. 1998, p. 48; Opler et al. 1998, p. 363; Glassberg 
1999, p. 167; Brock and Kaufman 2003, p. 306). Layberry et al. (1998, 
p. 48) state ``. . . since it is a clear case of an original incorrect 
spelling it can be corrected [rule 32(c)ii of the International Code of 
Zoological Nomenclature].''
    Poweshiek skipperlings are small and slender-bodied, with a 
wingspan generally ranging from 2.3 to 3.0 cm (0.9 to 1.2 in). The size 
of Poweshiek skipperlings appears to vary somewhat across their range 
(Royer and Marrone 1992b, p. 3). North Dakota and South Dakota 
specimens tend to be slightly smaller than the 2.9 to 3.2 cm (1.1 to 
1.3 in) range given by Parker (1870) for the type specimens from 
Grinnell, Iowa (Royer and Marrone 1992b, p. 3). A sample of Richland 
County, North Dakota, specimens from Royer's collection had an average 
wingspan of 2.8 cm (1.1 in) for males and 3.0 cm (1.2 in) for females. 
South Dakota specimens in Marrone's collection had an average wingspan 
of 2.6 cm (1.0 in) for males and 2.7 cm (1.1 in) for females. The upper 
wing surface is dark brown with a band of orange along the leading edge 
of the forewing. Ground color of the lower surface is also dark brown, 
but the veins of all but the anal third of the hindwing are outlined in 
hoary white, giving an overall white appearance to the undersurface.
    The Poweshiek skipperling is most easily confused with the Garita 
skipperling (Oarisma garita), which can be distinguished from Poweshiek 
skipperling by their smaller size, quicker flight, and overall golden-
bronze color (Royer and Marrone 1992b, p. 3). Another distinguishing 
feature is the color of the anal area of the ventral hindwing (orange 
in Garita; dark brown in Poweshiek). The Garita skipperling generally 
occurs west of Poweshiek skipperling range, although there are records 
of both species from two counties in southeastern North Dakota and two 
counties in northwestern Minnesota (Montana State University--Big Sky 
Institute 2012, Butterflies of North America http://www.butterfliesandmoths.org, Accessed 5/14/12; Minnesota Department of 
Natural Resources (DNR) 2012, Rare features database. Accessed 5/14/
12).
    McAlpine (1972, pp. 85-92) described Poweshiek skipperling eggs as 
pale yellowish green, mushroom shaped with a flattened bottom, a 
slightly depressed micropyle (pore in the egg's membrane through which 
the sperm enter) and smooth surfaced. They were 0.8 millimeters (mm) 
(0.01 in) long, 0.7 mm (0.03 in) wide and 0.5 mm (0.02 in) high. The 
overall color of the head and body of the larvae is pale grass-green, 
with a distinctive darker green mid-dorsal stripe and seven cream-
colored stripes on each side. First instars were 1.8 mm (0.07 in) at 
hatching, and the lone 7th instar survivor was 23.6 mm (1.0 in) near 
the end of that stage. McAlpine did not have any observations past the 
7th instar (the stage between successive molts, the first instar being 
between hatching and the first molt) (McAlpine 1972, pp. 85-93).

General Life History

    Poweshiek skipperlings lay their eggs near the tips of leaf blades 
and overwinter as larvae on the host plants (Bureau of Endangered 
Resources in Swengel and Swengel 1999, p. 285, Borkin 2000, p. 7). 
Poweshiek skipperlings have also been documented laying eggs on the 
entire length of grass leaf blades and on low-growing deciduous foliage 
(Dupont 2013, p. 133). McAlpine (1972, pp. 85-92) described the various 
life-history stages of Poweshiek skipperling, and recent studies of 
captive Poweshiek skipperlings at the Minnesota Zoo provide additional 
information (Runquist 2013, pers. comm.). McAlpine (1972, pp. 85-93) 
observed hatching of larval Poweshiek skipperling after about 9 days. 
McAlpine's records were incomplete, and he did not have any 
observations past the 7th instar, but he believed that there should 
have been one or two additional instars, followed by the chrysalis 
(pupa) and then the imago (adult) stages (McAlpine 1972, pp. 85-93). 
Captive Poweshiek skipperling eggs hatched 8 to 9 days after 
oviposition (Runquist 2013, pers. comm.). After hatching, Poweshiek 
skipperling larvae crawl out near the tip of grasses and may remain 
stationary, with their head usually pointing downward (McAlpine 1972, 
pp. 88-92). Unlike Dakota skippers, Poweshiek skipperling do not form 
shelters underground (McAlpine 1972, pp. 88-92; Borkin 1995, p. 9; 
Borkin 2008, pers. comm.), instead the larvae overwinter up on the 
blades of grasses and on the stem near the base of the plant (Borkin 
2008, pers. comm.; Dana 2008, pers. comm.). Borkin (2008, pers. comm.) 
observed larvae moving to the tips of grass blades to feed on the outer 
and thinner edges of the blades, with later movement down and among 
blades. Mature Poweshiek skipperling caterpillars reared in captivity 
ranged in size from approximately 22 to 25 mm (0.9 to 1 inch) in length 
just prior to pupation (Runquist 2013, pers. comm.).

Food and Water

    For the Poweshiek skipperling, nectar plants vary across its 
geographic range. Smooth ox-eye (Heliopsis helianthoides) and purple 
coneflower were noted as the frequently visited nectar plants in Iowa, 
Minnesota, and North Dakota (Swengel and Swengel 1999, p. 280). Other 
nectar species used were stiff tickseed (Coreopsis palmata), black-eyed 
Susan, and palespike lobelia (Swengel and Swengel 1999, p. 280). On 
drier prairie habitats in Iowa and Minnesota, purple coneflower is used 
almost exclusively, and the emergence of the adults corresponds closely 
to the early maturity of this species' disk florets (Selby 2005, p. 5). 
On the wetter prairie habitats of Canada and the fen habitats of 
Michigan, favored nectar plants are black-eyed Susan, palespike 
lobelia, sticky tofieldia (Triantha glutinosa), and shrubby cinquefoil 
(Dasiphora fruticosa ssp. floribunda) (Nielsen 1970, p. 46; Holzman 
1972, p. 111; Catling and Lafontaine 1986, p. 65; Bess 1988, p. 13; 
Summerville and Clampitt 1999, p. 231). Recent studies in Manitoba 
indicate that the most frequently used nectar plants are black-eyed 
Susan, upland white aster, and self-heal (Prunella vulgaris) (Dupont 
2013, pp. 70-71). In addition to nutrition, the nectar of flowering 
forbs provides water for Poweshiek skipperling, which is necessary to 
avoid desiccation during flight activity (Dana 2013, pers. comm.).
    Until recently, the larval food plant was presumed to be elliptic 
spikerush (Eleocharis elliptica) or sedges, but this was based on 
limited observations, primarily from the Michigan populations (e.g., 
Holzman 1972, p. 113). More recent observations show that the preferred 
larval food plant for some populations of Poweshiek skipperling is 
prairie dropseed (Borkin 1995, p. 6); larvae have also been observed 
feeding on little bluestem (Schizachyrium scoparium) (Borkin 1995, pp. 
5-6) and sideoats grama (Bouteloua curtipendula) (Dana 2005a, pers. 
comm.). Poweshiek skipperling larvae have been observed feeding on 
Carex sp. (Borkin 1994, p. 6; Borkin 1996, p. 2), although not through 
the entire larval development (Borkin 2014, pers. comm.). Poweshiek 
skipperling

[[Page 63686]]

have been observed laying eggs (ovipositing) on mat muhly (Muhlenbergia 
richardsonis) (Cuthrell 2012a, pers. comm.), a grass in Michigan's 
prairie fens (Penskar and Higman 1999, p. 1). Captive-reared 
caterpillars fed most successfully on prairie dropseed, and older 
caterpillars (late 2-day instar and older) successfully fed on little 
bluestem, big bluestem, and side-oats gramma (Runquist 2013, pers. 
comm.). One post-diapause Poweshiek skipperling was successfully reared 
to adulthood on Pennsylvania sedge (Carex pensylvanica) (Runquist 2013, 
pers. comm.).
    In southwestern Minnesota dry hill prairies, Poweshiek skipperling 
oviposition was observed on prairie dropseed, little bluestem, big 
bluestem, porcupine grass, and a couple unidentified species; a larva 
was observed feeding on sideoats grama (Dana 2005a, pers. comm.). 
Poweshiek skipperlings were observed to oviposit on big bluestem in 
Wisconsin (Borkin 2012a, pers. comm.), although indiscriminate 
oviposition on unsuitable larval plants has been observed during high 
summer temperatures (Borkin 1995, p. 6). Borkin (1995, p. 4) also 
observed oviposition on an unidentified sedge (Eleocharis sp.), but 
only 2 eggs were found on the sedge in comparison to more than 100 eggs 
found on prairie dropseed. In Manitoba, Poweshiek skipperlings were 
observed ovipositing on big bluestem, white sweet clover, an 
unidentified goldenrod (Solidago spp.), and juvenile bur oak (Quercus 
macrocarpa) leaves (Dupont 2013, p. 73). Poweshiek skipperlings have 
also been documented laying eggs on the entire length of grass leaf 
blades, including the tips, and on low-growing deciduous foliage 
(Dupont 2013, p. 133). Dana (2013, pers. comm.) noted that larvae seem 
to begin feeding at a very fine, threadlike blade tip and females 
placed eggs on fine blade tips of grasses during some observed 
ovipositions. Consistent with field observations of female oviposition 
on fine blades of grass, captive-reared caterpillars (early instars) 
preferred feeding on finer leaf blades (Runquist 2013, pers. comm.).

Dispersal

    Poweshiek skipperlings are also not known to disperse widely; the 
species was evaluated among 291 butterfly species in Canada as having 
relatively low mobility; experts estimated Poweshiek skipperling to 
have a mean mobility of 2 (standard deviation = 1.4) on a scale of 0 
(sedentary) to 10 (highly mobile) (Burke et al. 2011, p. 2279; 
Fitzsimmons 2012, pers. comm.). A mark-recapture study was conducted in 
Manitoba in 2008 and 2009; however, only 2 of the 56 marked individuals 
in 2008 were recaptured and none of the 16 marked individuals in 2009 
were recaptured, so available data are insufficient to examine within 
and between site dispersal (Dupont 2013, pp. 68-70). After 2 days, the 
two recaptured individuals were within 50 m (165 ft) of their initial 
capture location (Dupont 2013, p. 69).
    Besides this study in Manitoba, which had too few recaptures to 
make any statistically significant conclusions, we are unaware of any 
other studies that documented the dispersal distance of the species. 
Therefore, we used the Dakota skipper as a surrogate species to 
estimate the maximum dispersal distance of Poweshiek skipperlings and 
verified our assumptions with expert review. In a mark-recapture study, 
average adult movements of Dakota skippers were less than 300 meters 
(m) (984 feet (ft)) during a period of 3-7 days; marked adults crossed 
less than 200 m (656 ft) of unsuitable habitat between two prairie 
patches and moved along ridges more frequently than across valleys 
(Dana 1991, pp. 38-40). Dana (1997, p. 5) later observed reduced 
movement rates across a small valley dominated by exotic grasses with 
roads and crop fields compared with movements in adjacent widespread 
prairie habitat. Roads and crop fields were suspected as impediments 
for movement among prairie patches along two sites of the main valley 
(Dana 1997, p. 5), although movements beyond the study area were beyond 
the scope of the 1997 mark-recapture study (Dana 2013, pers. comm.). 
Skadsen (1999, p. 2) reported possible movement of Dakota skippers in 
1998 from a known population at least 800 m (2,625 ft) away to a site 
with an unusually heavy growth of purple coneflower; he had not found 
Dakota skippers in three previous years when coneflower production was 
sparse.
    Based on expert opinion, a maximum dispersal distance of 1.6 km 
(1.0 mi) was estimated to be a reasonable and likely distance for male 
Poweshiek skipperling to travel between patches of prairie habitat 
separated by structurally similar habitats (e.g., perennial grasslands 
but not necessarily native prairie) (Westwood 2012a and 2012b, pers. 
comm.; Dana 2012b, pers. comm.). The species, however, will not likely 
disperse across habitat that is not structurally similar to native 
prairies, such as certain types of row crops or anywhere not dominated 
by grasses (Westwood 2012a and 2012b, pers. comm.; Dana 2012b, pers. 
comm.). In Manitoba, Poweshiek skipperling have been observed avoiding 
dispersal over short distances, even to suitable habitat, if a barrier 
such as a road exists between suitable prairie habitat and nectar 
sources (Westwood et al. 2012, p. 18).
    Since experts estimated Dakota skippers to have a mean mobility of 
3.5 (standard deviation = 0.7) on a scale of 0 (sedentary) to 10 
(highly mobile), which is higher than the estimate for the Poweshiek 
skipperling (mean mobility of 2) (Burke et al. 2011, p. 2279; 
Fitzsimmons 2012, pers. comm.), we used the estimated dispersal 
distance of the Dakota skipper, approximately 1 km (0.6 mi) (Cochrane 
and Delphey 2002, p. 6), which is more conservative than the 1.6 km 
(1.0 mi) estimated for the Poweshiek skipperling by expert opinion 
(Westwood 2012b, pers. comm., Dana 2012b, pers. comm.). One kilometer 
is a reasonable maximum dispersal distance, since no data documents the 
species that document a greater distance travelled.
    In summary, using the best information available, dispersal of 
Poweshiek skipperling is very limited due in part to its short adult 
life span and single annual flight. Therefore, the species' extirpation 
from a site is likely permanent unless it is within about 1 km (0.6 mi) 
of a site that generates a sufficient number of emigrants or is 
artificially reintroduced to a site; however, the capability to 
propagate the Poweshiek skipperling is currently lacking.

Habitat

    Poweshiek skipperling habitats include prairie fens, grassy lake 
and stream margins, moist meadows, sedge meadow, and wet-to-dry 
prairie. McCabe and Post (McCabe and Post 1977, pp. 36-38) describe the 
species' habitat in North Dakota as ``. . . high dry prairie and low, 
moist prairie stretches as well as old fields and meadows.'' Royer and 
Marrone (1992b, p. 12) describe Poweshiek skipperling habitat in North 
Dakota and South Dakota as moist ground in undisturbed native tallgrass 
prairies. Poweshiek skipperling habitat throughout Iowa and Minnesota 
is described as both ``high dry'' and ``low wet'' prairie (McCabe and 
Post 1977, pp. 36-38). The only documented Illinois record was 
associated with high rolling prairie (Dodge 1872, p. 218); the only 
documented Indiana record was from marshy lakeshores and wetlands 
(Blatchley 1891, p. 398; Shull 1987, p. 29).
    Southern dry prairies in Minnesota are described as having sparse 
shrub cover (less than 5 percent) composed primarily of leadplant, with 
prairie rose,

[[Page 63687]]

wormwood sage, or smooth sumac present and few, if any, trees 
(Minnesota DNR 2012a, p. 1). Southern mesic prairies also have sparse 
shrubs (5-25 percent cover) consisting of leadplant and prairie rose 
with occasional wolfberry (Symphoricarpos occidentalis) and few, if 
any, trees (Minnesota DNR 2012b, p. 1).
    The disjunct populations of Poweshiek skipperlings in Michigan have 
more narrowly defined habitat preferences, variously described as wet 
marshy meadows (Holzman 1972, p. 114), bog fen meadows or carrs (Shuey 
1985, p. 181), sedge fens (Bess 1988, p. 13), and prairie fens 
(Michigan Natural Features Inventory 2011, unpubl. data; Michigan 
Natural Features Inventory 2012, unpubl. data); prairie fen is the 
currently accepted name for this habitat type. Bess (1988, p. 13) found 
the species primarily in the drier portions of Liberty Fen, Jackson 
County, dominated by ``low sedges'' and an abundance of nectar sources. 
Summerville and Clampitt (1999, p. 231) noted that the population was 
concentrated in areas dominated by spikerush and that only 10-15 
percent of the fen area was occupied despite the abundance of nectar 
sources throughout. Poweshiek skipperling have been described as 
occupying peat domes within larger prairie fen complexes in areas 
either dominated by mat muhly or prairie dropseed (Cuthrell 2013a, 
pers. comm.). A few prairie fens in Michigan also contain other rare 
butterflies, such as Mitchell's satyr and swamp metalmark (Cuthrell 
2013a, pers. comm.).
    Poweshiek skipperling populations in Wisconsin are also disjunct 
from the population to the west and are associated with areas that 
contain intermixed wet prairie, wet-mesic, and dry-mesic prairie 
habitats (Borkin 1995, p. 6; Swengel 2013, pers. comm.). The dry-mesic 
habitats in the Scuppernong Prairie contain ``extensive patches of 
prairie dropseed and little bluestem grasses'' (Borkin 1995, p. 7). 
Survival in wetter areas, which tend to burn cooler and less 
completely, coupled with low recolonization rates, or the 
disproportionate loss of wet versus dry prairie could give the false 
impression that the wet areas were their preferred habitat (Borkin 
1995, p. 7). Puchyan Prairie consists of wet-mesic prairie that grades 
lower into sedge meadow (WI DNR Web site http://dnr.wi.gov/topic/Lands/naturalareas/index.asp?SNA=172; Swengel 2013, pers. comm.) and adult 
Poweshiek Skipperlings have been observed in wet prairie there, 
although it is not known if these areas function as successful larval 
habitat (Swengel 2013, pers. comm.).
    Like the Dakota skipper, it has been hypothesized that Poweshiek 
skipperling larvae may be vulnerable to desiccation during dry summer 
months (Borkin 2012a, pers. comm.) and require movement of shallow 
groundwater to the soil surface or wet low areas to provide relief from 
high summer temperatures or dry conditions (Royer et al. 2008, pp. 2, 
16; Borkin 2012a, pers. comm.). Humidity may also be an essential 
factor to larval survival during winter months since the larvae cannot 
take in water during that time and depend on humid air to minimize 
water loss through respiration (Dana 2013, pers. comm.).
    Royer (2008, pp. 14-15) measured microclimatological (climate in a 
small space, such as at or near the soil surface) levels within 
``larval nesting zones'' (0 to 2 cm above the soil surface) at six 
known Poweshiek skipperling sites, and found an acceptable rangewide 
seasonal (summer) mean temperature range of 18 to 21 [deg]C (64 to 
70[emsp14][deg]F), rangewide seasonal mean dew point ranging from 14 to 
17 [deg]C (57 to 63[emsp14][deg]F), and rangewide seasonal mean 
relative humidity between 73 and 85 percent. Royer (2008) examined only 
occupied areas for these parameters; therefore, the statistical and 
biological significance of these edaphic variables cannot be determined 
from his study.
    Canadian populations of Poweshiek skipperlings are restricted to a 
single 2,300-ha (5,683-ac) area in southeastern Manitoba (COSEWIC 2003, 
p. 5). The wet to mesic tallgrass prairie in this area is characterized 
by low relief (1-2 m (3-7 ft)), with alternating lower, wetter areas 
and higher, drier prairie; Poweshiek skipperlings tend to be 
concentrated on or near the edge of the higher, drier prairie (COSEWIC 
2003, p. 8). Spikerush is frequent in the wetter areas, and prairie 
dropseed, black-eyed Susan, and palespike lobelia are frequent in the 
drier areas (COSEWIC 2003, pp. 7-8). The wet-mesic tallgrass prairies 
in Manitoba vary in size and occur along bluffs of Bur oak and 
trembling aspen (Populus tremuloides Michx.) (Catling and Lafontaine 
1986; Dupont 2013, p. 17). Little bluestem, big bluestem, and Indian 
grass were the three most common grasses in managed study plots in 
Manitoba (Dupont 2013, p. 85). Plant species generally associated with 
upland, drier portions of the mesic tallgrass prairies in Manitoba 
include: Big bluestem, pale-spike lobelia, prairie dropseed, mountain 
death camas, stiff goldenrod, black-eyed Susan, and meadow blazing-star 
(Environment Canada 2012, p. 6). In lower, wetter prairies with 
Poweshiek skipperlings, the following species are listed as often seen: 
Willow (Salix spp.), sedges (Carex spp.), rushes (Juncus spp.), 
groundsels (Pakera spp.), tufted hairgrass, creeping bentgrass 
(Agrostis stolonifera), mat muhly, elliptic spike-rush, four-flowered 
yellow loosestrife (Lysimachia quadriflora), and common self-heal 
(Environment Canada 2012, p. 6). Most of these plants were also 
commonly observed in study plots surveyed in 2008-2009 (Dupont 2013, p. 
86). The soils where the Poweshiek skipperling occurs in Manitoba are 
described as shallow, rocky, and highly calcareous (Westwood and 
Borkowsky 2004 in Dupont 2013, p. 19).
    Prairie fen habitat soils in Michigan are described as saturated 
organic soils (sedge peat and wood peat) and marl, a calcium carbonate 
(CaCO3) precipitate (MINFI Web site accessed August 3, 
2012). In other States, soil textures in Poweshiek skipperling habitats 
are classified as loam, sandy loam, or loamy sand (Royer et al. 2008, 
pp. 3, 10); soils in moraine deposits are described as gravelly, except 
the deposits associated with glacial lakes.

Population Distribution and Occupancy

    The Poweshiek skipperling is historically known from eight States, 
ranging widely over the native wet-mesic to dry tallgrass prairies from 
eastern North and South Dakota (Royer and Marrone 1992b, pp. 4-5) 
through Iowa (Nekola and Schlicht 2007, p. 7) and Minnesota (Minnesota 
DNR, Division of Ecological Resources, unpubl. data), with occurrences 
also documented in northern Illinois (Dodge 1872, p. 218), Indiana 
(Blatchley 1891, p. 898), Michigan (Holzman 1972, p. 111; McAlpine 
1972, p. 83), and Wisconsin (Borkin 2011, in litt.; Selby 2010, p. 22). 
The relatively recent discovery of Poweshiek skipperling populations in 
the Canadian province of Manitoba further extends its known historical 
northern distribution (Westwood 2010, pp. 7-22; Dupont 2010, pers. 
comm.). Additional historical accounts of Poweshiek skipperling from 
the States of Montana, Colorado, and Nebraska are likely 
misidentifications of its western congener, the Garita skipperling.
    Once common and abundant throughout native prairies in eight States 
and at least one Canadian province, the Poweshiek skipperling and its 
habitat have experienced significant declines. The species is 
considered to be present at a few native prairie remnants in two States 
and one location in Manitoba, Canada. The species is presumed 
extirpated from

[[Page 63688]]

Illinois and Indiana, and the status of the species is uncertain in 
four of the six States with relatively recent records (within the last 
20 years). The historical distribution of Poweshiek skipperling may 
never be precisely known because ``much of tallgrass prairie was 
extirpated prior to extensive ecological study'' (Steinauer and Collins 
1994, p. 42), such as butterfly surveys. Destruction of tallgrass and 
mixed-grass prairie began in 1830 (Sampson and Knopf 1994, p. 418), but 
significant documentation of the ecosystem's butterfly fauna did not 
begin until about 1960. Therefore, most of the decline of the Poweshiek 
skipperling probably went unrecorded. Poweshiek skipperling dispersal 
is very limited due in part to its short adult life span and single 
annual flight. Therefore, the species' extirpation from a site is 
likely permanent unless it is within about 1 km (0.6 mi) of a site that 
generates a sufficient number of emigrants or is artificially 
reintroduced to a site.
    Recent survey data indicate that Poweshiek skipperling has declined 
to zero or to undetectable levels at 96 percent of sites where it has 
ever been recorded. Until about 2003, Poweshiek skipperling was 
regarded as the most frequently and reliably encountered prairie-
obligate skipper butterfly in Minnesota, which contains approximately 
48 percent of all known Poweshiek skipperling locations rangewide. 
Numbers and distribution dropped dramatically in subsequent years, 
however, and the species was not seen in Minnesota from 2007 through 
2012. Two individuals were observed at one site in 2013 (Weber 2014, in 
litt.; Dana 2014, pers. comm.). In Iowa, the Poweshiek skipperling was 
found at 2 of 33 sites with previous records surveyed in 2007; the 
species was last observed at one site in 2008. Iowa contains about 14 
percent of documented sites rangewide. Unidentified threats to the 
species have acted to extirpate or sharply diminish populations at all 
or the vast majority of sites in Iowa and Minnesota (Dana 2008, p. 16; 
Selby 2010, p. 7).
    South Dakota historically contained about 23 percent of the 
rangewide sites with documented presence of Poweshiek skipperling, 
although recent surveys in that State also suggest an emergent and 
mysterious decline. The species was last observed in South Dakota in 
2008, at three sites. Surveys conducted in 2009-2013 flight seasons in 
South Dakota resulted in zero detections of the species. North Dakota 
historically contained about six percent of the rangewide sites with 
documented presence of Poweshiek skipperling; the species was last 
observed in North Dakota in 2001. Survey efforts in North Dakota have 
been minimal between 1998 and 2011, but surveys conducted in 1997 
documented more than 10 Poweshiek skipperlings at 1 site; 6 individuals 
were counted at 1 site, and 0 were detected at 6 other sites. Surveys 
conducted during the 2012 and 2013 flight seasons in North Dakota 
resulted in zero detections of the species.
    Seven Michigan sites were recently ranked as having good or better 
``viability,'' a habitat-based element occurrence rank assigned by the 
Michigan Natural Features Inventory (2011); however, the number of 
individuals observed at a few of those sites has declined in recent 
years, and the species is presumed extirpated from one of those sites. 
Currently, four of the ten extant occurrences of Poweshiek skipperling 
in Michigan are considered to have good or better viability (Michigan 
Natural Features Inventory (2011, unpubl. data). Each of those faces 
threats of at least low to moderate magnitude, and the State contains 
only about 6 percent of all known historical Poweshiek skipperling 
records. One population of Poweshiek skipperlings in Wisconsin had 
fairly consistent numbers observed over the last 5 years (17 to 63 
individuals counted using modified Pollard transect covering 15 ac (6 
ha) in approximately 40 minutes), but the species was not observed in 
2013 surveys. One population in Manitoba has fairly consistent numbers 
(typically hundreds of individuals observed each year). To summarize, 
of the 298 documented sites, there are 12 sites where we consider the 
Poweshiek skipperling to be present, 111 sites with unknown status, 96 
possibly extirpated sites, and 79 where we consider the species to be 
extirpated (Table 2). The distribution and status of Poweshiek 
skipperling in each State of known historical or extant occurrence are 
described in detail below.

Table 2--Number of Historically Documented Poweshiek Skipperling Sites Within Each State and the Number of Sites
             Where the Species Is Thought To Be Present, Unknown, Possibly Extirpated, or Extirpated
----------------------------------------------------------------------------------------------------------------
                                      State's
                                     percentage
                                       of the
               State                   total       Present      Unknown      Possibly    Extirpated     Total
                                     number of                              extirpated
                                     historical
                                       sites
----------------------------------------------------------------------------------------------------------------
Illinois..........................          1.3  ...........  ...........  ...........            4            4
Indiana...........................          0.3  ...........  ...........  ...........            1            1
Iowa..............................         13.8  ...........            4           24           13           41
Michigan..........................          5.7            9            2  ...........            6           17
Minnesota.........................         48.3            1           58           64           21          144
North Dakota......................          5.7  ...........            8            6            3           17
South Dakota......................         23.2  ...........           36            2           31           69
Wisconsin.........................          1.3            1            3  ...........  ...........            4
Manitoba..........................          0.3            1  ...........  ...........  ...........            1
                                   -----------------------------------------------------------------------------
    Total Number of Historically    ...........           12          111           96           79          298
     Documented Sites.............
Percent of the Total Number of      ...........           4%          37%          32%          27%  ...........
 Historical Sites by Occupancy....
----------------------------------------------------------------------------------------------------------------

Illinois
    The Poweshiek skipperling historically occurred in Illinois, 
although only one historical occurrence is supported (Table 2). In the 
early 1870s, Dodge (1872, p. 218) reported abundant Poweshiek 
skipperling occupying ``the high rolling prairie that forms the divide 
between the Illinois

[[Page 63689]]

and Rock rivers'' in Bureau County, Illinois. In addition to Bureau 
County, the Web site Butterflies and Moths of North America lists 
Poweshiek skipperling historical occurrences for Lake and Mason 
Counties, which were submitted to the Web site before the date field 
was required, so a default date of January 1, 1950, was assigned, which 
is outside of the typical flight period (http://www.butterfliesandmoths.org/species/Oarisma-poweshiek; accessed August 
16, 2012). The Web site maintains a verifiable database on species 
occurrences, but there is no accessible supporting data for the Lake 
and Mason Counties records (Lundh 2012, pers. comm.). One additional 
record, housed at University of Wisconsin-Oshkosh, was collected in 
DuPage County in 1968 and was recently identified as a Poweshiek 
skipperling. The location where the specimen was collected has since 
been converted and is no longer a prairie, and it is presumed that the 
species is extirpated from that location (Borkin 2014, pers. comm.). 
Poweshiek skipperling is, therefore, presumed to be extirpated from 
Illinois.
Indiana
    There is one supported historical occurrence of Poweshiek 
skipperlings in Indiana (Table 2). Blatchley (1891, p. 898) reported 
small numbers of Poweshiek skipperlings near Whiting, Indiana; Shull 
(1987, p. 49) expressed confidence that this record is authentic. The 
Poweshiek skipperling is considered extirpated from Indiana.
Iowa
    Iowa historically contained approximately 14 percent (N=41) of all 
known records of Poweshiek skipperlings rangewide (Table 2). The 
Poweshiek skipperling was historically known to occur at 38 sites in 13 
counties in Iowa (Nekola 1995, p. 8; Saunders 1995, pp. 27-28; Selby 
2005, p. 18; Nekola and Schlicht 2007, p. 7; Selby 2010, p. 6); 
however, this number may vary slightly (up to 41 sites) depending on 
how one divides sites along the Little Sioux River in the Freda-Cayler 
area (Selby 2012a, pers. comm.). Early reports from Parker (1870, p. 
271) described Poweshiek skipperling as abundant on a prairie slope at 
Grinnell, Iowa, while Lindsey (1917, p. 352; 1920, p. 320) noted 
additional rare occurrences in Story, Dickinson, Poweshiek, and 
Woodbury Counties, Iowa--among these, habitat has long since been 
destroyed in all but Dickinson County.
    In 1993-1994, 65 sites were surveyed in 17 counties where Dakota 
skipper or Poweshiek skipperling had been previously recorded or where 
prairie and butterfly surveys or infra-red photography suggested the 
presence of Poweshiek skipperling habitat (Saunders 1995, pp. 7-8). 
Among the 65 sites surveyed, Poweshiek skipperlings were found at 29 
sites in 10 counties (Saunders 1995, p. 27). In 2000, Poweshiek 
skipperlings were found at six sites surveyed in and near Cayler 
Prairie and Freda Haffner Kettlehole State preserves in Dickinson 
County (Selby 2000, p. 19). Followup surveys of this complex in 2004, 
2005, and 2007, however, produced no confirmed sightings (Selby 2010, 
p. 6). Extensive surveys were conducted in 2007, and included 32 of the 
38 sites in the State with post-1990 records (Selby 2008, pp. 4, 6). 
Poweshiek skipperlings were found at 2 of the 38 sites surveyed--
Hoffman Prairie State Preserve in Cerro Gordo County and Highway 60 
Railroad Prairie in Osceola County (Selby 2008, pp. 6-7). Five of the 
six sites not included in the 2007 surveys had very little quality 
prairie (Selby 2012a, pers. comm.). Supplementary surveys conducted 
further west along U.S. Highway 18 in Hancock County also produced no 
confirmed sightings (Selby 2010, p. 7). No surveys were conducted at 
previously known Poweshiek skipperling sites in the State during the 
2012 flight season. No Poweshiek skipperlings were observed in surveys 
in 2013 at two sites with relatively recent records of the species 
(2005 and 2008) (Olsen 2013, p. 2).
    The Poweshiek skipperling is presumed extirpated or possibly 
extirpated from all but four of the known sites in Iowa. The status of 
the Poweshiek skipperling is unknown at four sites: Highway 60 Railroad 
Prairie, Floete Prairie in Dickinson County, Florenceville Prairie, and 
Hayden Prairie in Howard County. There have been no surveys at Highway 
60 Railroad Prairie since the species was observed there in 2007 (Selby 
2012a, pers. comm.). The last observation of Poweshiek skipperling at 
Floete Prairie was in 1994, and the habitat ``did not appear to be very 
good quality'' in 2007, although the site was not surveyed for 
butterflies that year (Selby 2012a, pers. comm.) or in subsequent 
years. The Poweshiek skipperling was last observed at the Florenceville 
Prairie in 1994 (Saunders 1995, p. 27), but not during the 2007 survey 
year (Selby 2010, pp. 8-11). The species was last observed at Hayden 
Prairie in 2005, but not during surveys conducted in 2007 (Selby 2010, 
p. 10) or 2013 (Olsen 2013, p. 2). Four Poweshiek skipperlings were 
found at Hoffman Prairie in Cerro Gordo County in 2008 (Selby 2009b, p. 
3), but none were found during surveys in 2009 (Selby 2009b, p. 7) and 
2010 (Selby 2010, p. 7). We initially assigned an unknown status to the 
Hoffman Prairie site because the species had not been seen in the 2009 
and 2010 survey years; however, Selby believes that the species may be 
extirpated from this site (Selby 2012a, pers. comm.), so we assigned a 
status of extirpated to this site, which was confirmed with negative 
surveys in the 2013 flight season (Olsen 2013, p. 2).
    To summarize, the Poweshiek skipperling was historically documented 
in 41 sites in Iowa. The species occupancy is unknown at 4 of those 
sites, and the species is considered to be extirpated or possibly 
extirpated at 13 and 24 sites, respectively (Table 2). The species is 
not considered to be present at any of the sites in Iowa.
Michigan
    Michigan historically contained approximately 6 percent (N=17) of 
all known records of Poweshiek skipperlings rangewide (Table 2). 
Poweshiek skipperling has been historically documented at 17 sites in 6 
counties in Michigan. The species was first recorded in Michigan in 
1893 at Lamberton Lake near Grand Rapids in Kent County (Holzman 1972, 
p. 111) and then at nearby Button Lake Fen (also known as Emerald Lake 
Fen) in 1944 (McAlpine 1972, p. 83). Shrubs have invaded both sites, 
however, and no Poweshiek skipperlings have been found at either of 
these two western Michigan sites since 1944 and 1968, respectively 
(Michigan Natural Features Inventory 2011, unpubl. data). Holzman 
(1972, p. 111) documented Poweshiek skipperling in Oakland County in 
1970, and the species has since been found at a total of 15 locations 
in eastern Michigan.
    The Poweshiek skipperling is currently considered to be present at 
nine sites (Table 2) in four counties in Michigan: Jackson, Lenawee, 
Oakland, and Washtenaw. The species has been observed recently (2008-
2013) at most of those sites, except at the Liberty Bowl Fen in Jackson 
County, which has not been surveyed since one individual was observed 
in 1996. The status of the species is unknown at two sites; Bullard 
Lake in Livingston County, where Poweshiek skipperlings were last seen 
in 2007, but not in subsequent surveys in 2008 and 2009 (Cuthrell 
2012a, pers. comm.), and Liberty Fen (Grand River Fen) in Jackson 
County, where Poweshiek skipperlings were observed in 2012 but not in 
2013 surveys

[[Page 63690]]

(Cuthrell 2013, pers. comm.). The species is presumed extirpated from 
six sites including the only two sites in Kent County and three sites 
in Oakland County: Rattalee Road, Fenton Road, and Rattalee Lake Fen 
(Call C Burr Preserve) fens. The species has not been observed at the 
Rattalee Road and Fenton Road sites since 1970 and 1973, respectively 
(Michigan Natural Features Inventory 2011, unpubl. data). Four 
Poweshiek skipperlings were seen in 2009 at the Rattalee Lake Fen 
(Calla C Burr Preserve), but none were observed during surveys 
conducted in 2010, 2011, and 2012 (Cuthrell 2012a, pers. comm.; 
Michigan Natural Features Inventory 2011, unpubl. data). The Michigan 
Natural Features Inventory (MNFI) also considers the two sites in Kent 
County to be extirpated due to habitat loss and destruction, Lamberton 
Lake and Button Lake (also known as Emerald Lake); the species has not 
been observed at either site since 1968 and 1944, respectively. The 
species is presumed to be extirpated at Whalen Lake Fen in Livingston 
County, where the species has not been observed since 1998 despite 
three subsequent years of surveys (Michigan Natural Features Inventory 
2011, unpubl. data).
    Four of Michigan's nine extant (present) Poweshiek skipperling 
occurrences were recently considered to have at least good viability 
(Michigan Natural Features Inventory 2011, unpubl. data); however, 2013 
survey results have put the viability in question. Three of these 
sites, Buckhorn Lake also known as Big Valley), Brandt Road Fen (also 
known as Holly Fen) and Long Lake Fen, are within 20 km (12 mi) of one 
another in Oakland County; all with relatively large numbers (61-389) 
of the species recorded in 2010-2012 surveys (Michigan Natural Features 
Inventory 2011, unpubl. data; Cuthrell 2012a, pers. comm.). In 2013, 
however, 2 individuals (0.008/hr.) were recorded at Buckhorn Lake, 
which was down from 84 individuals (0.35/hr.) recorded the previous 
survey year (2012) with similar effort, and 53 individuals (0.33/hr.) 
were recorded at Brandt Road in 2013, down from 71 individuals (0.59/
hr.) recorded the previous survey year (2012) with similar effort. The 
largest extant (present) Poweshiek skipperling population in Michigan 
may be at Long Lake Fen, where 25 individuals (0.2/hr.) were counted 
during 2013 surveys, down from 389 individuals (2.2/hr.) and 225 
individuals (1.3/hr.) observed in the previous two survey years (2011 
and 2012, respectively) with similar sampling effort. In 2012, Long 
Lake Fen was thought to be the largest population of Poweshiek 
skipperling in the United States. However, it is subjected to intense 
development pressure, and results from 2013 surveys show low numbers. A 
fourth site, Grand River Fen (also known as Liberty Fen) in Jackson 
County, is approximately 100 km (62 mi) from the other three sites, and 
was also considered to have good viability in 2011, but the viability 
is questionable since 2013 surveys for the species were negative. In 
2010, researchers counted 54 (0.3/hr.) Poweshiek skipperling at Grand 
River Fen, and 114 (0.6/hr.) in 2011 (Michigan Natural Features 
Inventory 2011, unpubl. data; Cuthrell 2012a, pers. comm.). This number 
fell to 14 (0.1/hr.) in 2012 and zero in 2013 (Cuthrell, 2012a, pers. 
comm.; 2012b, pers. comm.; 2013, pers. comm.).
    Small populations, immediate threats that have significant impacts 
on the species, or both limit the viability of the remaining five sites 
where we consider Poweshiek skipperling to still be present in 
Michigan. In 2010, eight (0.1/hr.) Poweshiek skipperlings were recorded 
at Park Lydon in Washtenaw County; 12 individuals were counted in 2011 
(0.1/hr.), 22 were counted in 2012 (0.2/hr.), and 1 individual was 
counted in 2013 (Cuthrell 2012a, pers. comm.; 2013, pers. comm.). Two 
individuals (0.02/hr.) were recorded at Goose Creek Grasslands (also 
known as Little Goose Lake Fen) in Lenawee County in 2010, and nine 
(0.07/hr.) were seen in 2011 (Cuthrell 2012a, pers. comm.; 2012b, pers. 
comm.). Only one Poweshiek skipperling was seen during a 15-minute 3-
person survey in 2007 at the Snyder Lake site. Fourteen individuals 
were observed during 2008 surveys at Halstead Lake Fen (Michigan 
Natural Features Inventory 2011, unpubl. data), and 18 were observed in 
2012 (Cuthrell 2012a, pers. comm.); neither survey year had units of 
effort associated with the counts at this site. One individual was 
counted at Bullard Lake fen in 2007, but the species was not observed 
in the two most recent survey years (2008 and 2009); therefore, the 
status is unknown at that site. We have only one year of data from 
Liberty Bowl Fen, where the species was recorded in 1996. The Eaton 
Road Fen is thought to be fairly viable, where 15-20 individuals were 
observed on multiple occasions in 2005, and a high of 68 individuals 
were observed in 2011 (Cuthrell 2012b, pers. comm.). The Eaton Road 
site is approximately 0.6 km (1 mi) from the Long Lake Fen site and is 
considered a sub-site within Long Lake Fen (Cuthrell 2012b, pers. 
comm.), but we consider it to be a separate site for the purposes of 
this rule.
    To summarize, Poweshiek skipperling was historically documented in 
17 sites in Michigan (Table 2). The species is considered to be present 
at 9 of the sites, although the numbers observed in 2013 were 
substantially less than in previous years with similar survey effort. 
The occupancy is unknown at 2 sites, and the species is considered to 
be extirpated at 6 sites.
Minnesota
    Minnesota historically contained approximately 48 percent (N=144) 
of all known records of Poweshiek skipperlings rangewide (Table 2). 
There are approximately 189 historical Poweshiek skipperling occurrence 
records in 32 counties in Minnesota [Minnesota Natural Heritage 
Inventory (MN NHI) database accessed June 19, 2013, plus additional 
surveys]. Clusters of records occur within five general areas from the 
State's southwest corner to near the Canadian border in the north. 
Based on the proximity of some occurrences to one another (e.g., 
overlapping or occurrences in close proximity to one another in one 
general location), there appear to be approximately 144 distinct 
historical site records in the State (Dana 2012d, pers. comm; Service 
2014, unpubl. geodatabase). Poweshiek skipperling are presumed 
extirpated or possibly extirpated from at least 85 of these known 
sites. The status of the species is unknown at 58 sites, although 27 of 
those locations have not been surveyed since 2003, and the species has 
undergone a sharp decline in the State since then.
    An extensive survey effort was completed in 1993 and 1994 (Schlicht 
and Saunders 1994, entire; Schlicht and Saunders 1995, entire). During 
those surveys, Poweshiek skipperlings were found in 11 of 19 sites on 
which the species had been previously recorded and in 13 new sites, for 
a total of 25 of 63 surveyed prairie sites; the species was present at 
30 and 39 percent of the sites in 1993 and 1994, respectively (Schlicht 
and Saunders 1995, pp. 5-7). These results contrast sharply with those 
from the surveys conducted in 2007 and 2008, when the species was found 
at four and zero percent of sites, respectively. Although the species 
was apparently more common in 1993 and 1994, numbers of Poweshiek 
skipperling found during surveys were typically low. Large numbers were 
observed at only three sites (Schlicht and Saunders 1995, p. 4). At one 
of these sites, Glynn Prairie, 25 Poweshiek skipperling were recorded 
during a 50-minute survey in July 1993 (Schlicht and Saunders 1995, 
data sheet); no Poweshiek skipperling were observed at this site during 
the

[[Page 63691]]

2007 survey despite good survey conditions (Selby 2009a, p. xxxv).
    Until about 2003, the Poweshiek skipperling was regarded as ``the 
most frequently and reliably encountered prairie-obligate skipper in 
Minnesota'' (Dana 2008, p. 1). Signs of the species' decline in 
Minnesota were noted in 2003 when Selby (2005, p. 20) found sharply 
lower numbers in and near Glacial Lakes State Park (Selby 2005, p. 20) 
compared to those observed in 2001 (Skadsen 2001, pp. 22-24). For 
example, numbers recorded along four transects that were surveyed in 
both years decreased from 104 to 2 individuals (Selby 2006b, Appendix 
2, p. ii). In 2004 and 2005, Selby (2006b, Appendix 2, p. 2) did not 
record a single Poweshiek skipperling on any of these transects in and 
around the park during 11 separate surveys.
    An extensive survey effort was conducted in 2007 and 2008 
throughout most of the species' known range in the State (Selby 2009a, 
entire). Sites with previous Poweshiek skipperling records that were 
considered to have the greatest conservation importance to the species 
(large, high-quality prairie remnants) were surveyed, as well as sites 
with no previous records that appeared likely to support the species 
(Selby 2009a, p. 2). In 2007, 70 sites in 15 counties were surveyed, 
including 26 sites with previous Poweshiek skipperling records (Selby 
2009a, pp. 1, 6). In 2008, 58 sites were surveyed in 13 counties, 
including 22 sites with prior records (Selby 2009a, pp. 1, 6). A total 
of 34 sites with previous Poweshiek skipperling records were surveyed 
in both years combined. Poweshiek skipperling presence was recorded on 
only three of the 70 surveyed sites in 2007; each of these three sites 
had just one confirmed individual (Selby 2009a, p. 1). No Poweshiek 
skipperlings were observed on any of the 58 sites surveyed during the 
2008 flight period (Selby 2009a, p. 1).
    In 2007, multiple transect surveys were conducted in four sites 
with previously well-documented Poweshiek skipperling populations--
transects totaling 52,985 m (33 mi) were surveyed without observing a 
single Poweshiek skipperling (Dana 2008, p. 5). About half of these 
transects (totaling 20,959 m (13 mi)) were in the Prairie Coteau 
Scientific and Natural Area (SNA), where in 1990 Selby recorded 116 
Poweshiek skipperlings during the flight peak (Selby and Glenn-Lewin 
1990, pp. 19-20) along a total of about 6,250 m (4 mi) of transects 
(Dana 2008, p. 16). No Poweshiek skipperling were observed during 
surveys of the Prairie Coteau SNA in 2012 (Runquist 2012, pp. 9-10).
    Additional surveys were conducted in 2012; however, Poweshiek 
skipperling were not observed at any of the 18 sites with relatively 
recent records (Runquist 2012, pp. 4-25; Selby 2012, p. 2; Selby 2013, 
p. 2; Dana 2012c, pers. comm.; Runquist 2012a, pers. comm.; Olsen 
2012a, pers. comm.). Fifteen additional prairie sites with potential 
habitat or records of other skippers were surveyed in 2012, but no 
Poweshiek skipperling were observed (Runquist 2012, pp. 4-25; Selby 
2012, p. 2; Selby 2013, p. 2; Dana 2012c, pers. comm.; Runquist 2012a, 
pers. comm.; Olsen 2012a, pers. comm.). Twenty-one sites with previous 
records of the species were resurveyed in 2013 and 7 additional sites, 
with no previous records, were also surveyed for the species (Runquist 
2014, pp. 3-6; Selby 2014, pp. 2-5; Rigney 2013b, p. Appendix B). Three 
individual Poweshiek skipperlings were observed at one site in Polk 
County--this is the first credible sighting of the species in the State 
since 2007 (Webster 2013, pers. comm.; Dana 2014, pers. comm.; Service 
2014, unpub. database).
    Nearly half (approximately 48 percent) of all documented Poweshiek 
skipperling sites rangewide are in Minnesota, thus the apparent 
collapse of large numbers of Poweshiek skipperling populations across 
the State may pose a significant challenge for the long-term existence 
of this species. Although the possibility remains that the species is 
extant at some sites where recent (2007, 2008, 2012, or 2013) surveys 
were negative, it seems unlikely that it is present at those sites in 
any significant numbers. Extensive surveys in 1993 and 1994 documented 
the species at about 35 percent of all surveyed sites, whereas the 2007 
effort found them at only about 2 percent of all sites surveyed; no 
Poweshiek skipperling were detected despite widespread and robust 
survey efforts involving multiple observers in 2008 or 2012 (Dana 2008, 
p. 8; Selby 2009a, p. 1; Dana 2012c, pers. comm.; Runquist 2012a, pers. 
comm.; Olsen 2012, pers. comm.; Runquist 2012, pp. 4-25; Selby 2012, p. 
2, 2013, p. 2). Three individuals were sighted at one location in 2013 
(Webster 2013, pers. comm.; Dana 2014, pers. comm.).
    To summarize, Poweshiek skipperling was historically documented in 
approximately 144 sites in Minnesota (Table 2). The species is not 
considered to be present at any of these sites, except at one location 
(Table 2). The occupancy is unknown at 58 sites, and the species is 
considered to be extirpated or possibly extirpated at 21 and 64 sites, 
respectively (Table 2).
North Dakota
    North Dakota historically contained approximately 6 percent (N=17) 
of all known records of Poweshiek skipperlings rangewide (Table 2). 
Poweshiek skipperlings have been historically documented at 17 sites 
(Table 2) in 7 North Dakota counties (Selby 2010, p. 18; Service 2014, 
unpubl. geodatabase): Cass, Dickey, LaMoure, Ransom, Richland, and 
Sargent in the southeastern corner of the State and Grand Forks County 
in the Northeast. Poweshiek skipperling are now considered extirpated 
or possibly extirpated from nine sites and four counties (Cass, Dickey, 
LaMoure, and Grand Forks) in North Dakota. The status of the species is 
unknown at 8 sites, where the species was last observed between 1996 
and 2001, but not during the most recent 1-2 year(s) surveyed. Four 
sites with fairly recent Poweshiek skipperling records were surveyed in 
2012; Poweshiek skipperling were not found at any of those sites (Royer 
and Royer 2012b, pp. 21-24; Royer and Royer 2012a, p. 6). One 
additional site was surveyed, which had the potential for Poweshiek 
skipperling presence because of its proximity to a known site for the 
species; however, no Poweshiek skipperling were found (Royer and Royer 
2012b, pp. 18-19; Royer and Royer 2012a, p. 6; Royer 2012b, pers. 
comm.). The species was not observed at six sites with previous records 
of Poweshiek skipperlings that were surveyed in 2013. The species 
occupancy at two of these sites with 2013 surveys was updated from 
unknown to extirpated based on three consecutive years of negative 
surveys (Service 2014, unpubl. geodatabase).
    The Poweshiek skipperling was known from seven North Dakota sites 
across six counties in the 1990s; however, only two of those sites were 
considered to have extant populations at that time; three records were 
represented by incomplete or ambiguous locality data, and the species 
was assumed to be extirpated at one site (Royer and Marrone 1992b, pp. 
8-11). Surveys conducted in the State after 1992 documented additional 
populations, but the most recent surveys at these sites were mostly 
negative. Orwig discovered eight new populations of Poweshiek 
skipperling (six in Richland County and two in Sargent County) during 3 
years of survey work (1995-1997) in southeastern North Dakota (Orwig 
1995, pp. 3-4; Orwig 1996, pp. 4-6, 9-12; Orwig 1997, p. 2). The 
species was found at two of the eight sites surveyed in 1997 (Orwig

[[Page 63692]]

1997, p. 2) and at two additional sites in 1996 (Spomer 2004, p. 11).
    Once abundant at several known sites in North Dakota, Poweshiek 
skipperlings have experienced a dramatic decline over the last few 
decades. In 1977, McCabe and Post (1977a, p. 38), for example, found 
Poweshiek skipperling to be abundant at McLeod Prairie in Ransom 
County, stating that they could ``be collected two at a time on the 
blossoms of Long-headed coneflower . . .'' In 6 years of subsequent 
monitoring (1986-1991), however, Royer failed to find a single 
Poweshiek skipperling at the site after it was converted to a cattle-
loading area (Royer and Marrone 1992b, p. 10). Royer and Marrone 
(1992b, pp. 10-11) assumed the species had been extirpated at this 
site. Similarly, the number of Poweshiek skipperlings recorded during 
surveys at the West Prairie Church site along the boundary of Cass and 
Richland counties, fell from hundreds in 1986, to four in 1990, and 
zero in 1991 and 2012 (Royer and Marrone 1992b, p. 8; Royer and Royer 
2012b, p. 21). Poweshiek skipperlings are unlikely to persist at this 
small and isolated site (Royer and Royer 2012b, p. 21; Royer 2012c, 
pers. comm.).
    The last observation of a live Poweshiek skipperling in North 
Dakota was in 2001, at a new site discovered by Spomer (2001, p. 9) in 
Ransom County. Poweshiek skipperlings were not found in subsequent 
surveys at this site in 2002, 2003, and 2012 (Spomer 2001, p. 2; Spomer 
2002, p. 3; Spomer 2004 p. 36; Selby 2010, p. 18; Royer and Royer 
2012b, p. 22), although the 2012 survey may have been conducted too 
late in the year to detect the species at that site (Royer 2012b, pers. 
comm; Royer 2012d, pers. comm.). Therefore, the status of the species 
at this site is unknown.
    To summarize, Poweshiek skipperling was historically documented in 
17 sites in North Dakota (Table 2). The species is not considered to be 
present at any of these sites (Table 2). The occupancy is unknown at 
eight sites, and the species is considered to be extirpated or possibly 
extirpated at three and six sites, respectively (Table 2).
South Dakota
    South Dakota historically contained approximately 24 percent (N=69) 
of all known records of Poweshiek skipperlings rangewide (Table 2). The 
Poweshiek skipperling has been historically documented at approximately 
69 sites (Table 2) across 10 counties in South Dakota (Selby 2010, p. 
19). Based on expert review and additional survey and habitat 
information, the status of the species was determined to be unknown at 
36 sites, possibly extirpated at 2 sites, and presumed extirpated at 
the remaining 31 sites (Table 2); at least 8 of the extirpated sites 
have been destroyed by conversion, gravel mining, loss of native 
vegetation, flooding, or heavy grazing (Skadsen 2012c, pers. comm.).
    The Poweshiek skipperling was not detected at any site that was 
surveyed between 2009 and 2013: 6 sites in 2009, 10 sites in 2010, 1 
site in 2011, 10 sites in 2012, and 25 sites in 2013 (Skadsen 2009, p. 
12; Skadsen 2011, p. 5; Skadsen 2010, pers. comm.; Skadsen 2012a, pers. 
comm.; Skadsen 2012b, p. 3; Skadsen 2013, pp. 3-4). The 2009 to 2013 
results are in marked contrast to surveys conducted in 2002 when the 
species was recorded at 23 of 24 sites surveyed (Skadsen 2003, pp. 11-
45). Cool and wet weather may have depressed butterfly populations, in 
general, in eastern South Dakota and west-central Minnesota in 2009 as 
it apparently did in 2004 (Skadsen 2004, p. 2; Skadsen 2009, p. 2). In 
2012 and 2013, five and nine additional sites, respectively, with 
potentially suitable native-prairie habitat but with no previous 
records of the species were surveyed, but no Poweshiek skipperling were 
observed (Service 2014, unpubl. geodatabase).
Wisconsin
    Wisconsin historically contained approximately 1 percent (N=4) of 
all known records of Poweshiek skipperlings rangewide (Table 2). 
Naturalists reported Poweshiek skipperling to be common to abundant on 
prairies in southeastern Wisconsin in the late 1800s (e.g., in 
Milwaukee and Racine Counties), although exact localities are unknown 
(Borkin 2011, in litt.; Selby 2010, p. 22). By 1989, however, the 
species was listed as State endangered (Borkin 2011, in litt.). The 
Poweshiek skipperling is considered to be present at one site in 
Wisconsin (Table 2); Puchyan Prairie State Natural Area (SNA) is 
approximately 100 km (62 mi) to the northwest of the Kettle Moraine 
State Forest in Green Lake County. The status of the species is unknown 
at three sites within the Southern Unit of the Kettle Moraine State 
Forest in Waukesha County. An additional 2010 record of a butterfly was 
incorrectly identified as a Poweshiek skipperling at Melendy's Prairie 
Unit of the Scuppernong Prairie SNA (Borkin 2012b, pers. comm.).
    The two occurrences of Poweshiek skipperling in the Kettle Moraine 
State Forest inhabit small areas that were once part of a larger 
prairie complex, which was fragmented by conversion to agriculture, 
other human development, and encroachment of woody vegetation (Borkin 
2011, in litt.). Up until 2013, the largest population in Wisconsin was 
within a 6-ha (15-ac) prairie remnant on Scuppernong Prairie SNA at 
Kettle Moraine State Forest, which had record counts exceeding 100 
individuals in 1994, 1995, 1998, and 1999 (Borkin 1995, p. 10; Borkin 
1996, p. 7; Borkin 2000, p. 4; Borkin 2011, in litt.). Four were found 
in 2007 (Borkin 2008, in litt., p. 1), although these data were 
collected during a single transect survey that may have been early in 
the flight season and are, therefore, not comparable to other survey 
years (Borkin 2012a, pers. comm.). A maximum count of 42, 17, 63, and 
45 were counted in 2009, 2010, 2011, and 2012, respectively (Borkin 
2011a, pers. comm.; Borkin 2012c, pers. comm.). The relatively low 
maximum count in 2010 may be due to the timing of the flight (early) 
and the timing of the survey effort (late); therefore, the peak flight 
may have been missed (Borkin 2013, pers. comm.). A controlled burn in 
late March of 2012 may correlate with lower numbers observed during the 
2012 flight (Borkin 2012a, pers. comm.). While this difference may be 
within the range of variation observed over the previous 4 years 
(Wisconsin DNR 2012, in litt.), the range in variation may be skewed 
due to the low numbers observed in 2010 due to the timing of the flight 
and the survey effort (Borkin 2013, pers. comm.). No Poweshiek 
skipperlings were observed at Scuppernong during repeated surveys in 
2013 (Borkin 2013, pers. comm.)--this is the first time no individuals 
have been observed there since regular surveys began in the 1990s 
(Borkin 2014 pers. comm.). Each year, surveys were conducted with 
similar effort--modified Pollard transect covering 15 ac (6 ha) in 
approximately 40 minutes (Borkin 2014, pers. comm.).
    After brush was cleared from the area in 2002, a small number of 
Poweshiek skipperlings were discovered the following year in a small 
isolated prairie remnant patch at a second site in the Kettle Moraine 
State Forest, (Borkin in litt 2008). Once the intervening woody growth 
was removed, individuals presumably dispersed from the Scuppernong SNA 
remnant prairie to a small habitat patch about 200 ft (61 m) away 
(Borkin 2012a, pers. comm.). Surveys at each habitat patch have 
consistently yielded counts of less than 10 (Borkin 2008, in litt.), 
with a combined high count of 11 to 15 individuals in 2011. A total of 
six individuals, with a high single day count of three, were observed 
in eight surveys during 2012 (Borkin 2012c,

[[Page 63693]]

pers. comm.; Borkin 2012a, pers. comm.). No Poweshiek skipperlings were 
observed in 2013 (Borkin 2013, pers. comm).
    The status of the Poweshiek skipperling is unknown at a third and 
much larger fragment of Kettle Moraine State Forest, the Kettle Moraine 
Low Prairie SNA, which is adjacent to the Wilton Road site. The Kettle 
Moraine Low Prairie SNA was overgrown by shrubs including willows 
(Salix spp.), quaking aspen (Populus tremuloides), and glossy buckthorn 
(Frangula alnus) and has been managed with a series of controlled 
burns, in addition to a 1975 wildfire (Borkin 2011, in litt; Borkin 
2012a, pers. comm.; Wisconsin DNR 2012, in litt). The highest number 
recorded at the Kettle Moraine Low Prairie SNA was 28 on July 8, 1995 
(Borkin 2012a, pers. comm.). Preliminary attempts in 2000 to 2003 to 
augment the population with adults from Scuppernong SNA and captive-
reared larvae were not successful (Borkin 2012a, pers. comm.). A single 
Poweshiek skipperling was sighted there on July 2, 2004, but none were 
found in surveys conducted in 2007-2009 and 2011-2012 (Borkin 2011b, 
pers. comm.; Borkin 2012a and 2012c, pers. comm.). Two Poweshiek 
skipperlings were recorded in 2010 at this site (Wisconsin DNR2012, in 
litt.); however, no photographs or voucher specimens confirm the 
sighting. This site was surveyed less intensively than Scuppernong 
Prairie, because of the species' relatively low density and abundance 
at Kettle Moraine Low Prairie SNA (Borkin 2012a, pers. comm.). 
Extensive brush cutting, additional burns, and restoration of the 
hydrology have been undertaken in recent years (Borkin 2012a, pers. 
comm.).
    Poweshiek skipperlings are present at a third site in Wisconsin, 
Puchyan Prairie SNA, in Green Lake County, although this population is 
small and declining (Borkin 2009, pers. comm.). The Poweshiek 
skipperling was first discovered at Puchyan Prairie in 1995, and 6 to 
30 individuals have been recorded in subsequent surveys (Borkin 2008, 
in litt.; Swengel 2012, pers. comm). In 2012, Swengel (2012, pers. 
comm.) found a maximum of three individuals, despite several hours of 
searching over 3 days. In 2013, Swengel (2013, pers. comm.) found a 
total of three individuals during 2 days of searching.
    Additional sites in eight counties (Crawford, Grant, Iowa, 
Jefferson, Monroe, Rock, Sauk, and Walworth) have been surveyed in an 
attempt to find undiscovered Poweshiek skipperling populations. Four of 
the eight sites surveyed in 1998 and 1999 seemed to have adequate host 
plants, nectar resources, and size typical of Poweshiek skipperling 
habitat, but Poweshiek skipperling were not present at any of the sites 
(Borkin 2000, pp. 5-7).
    To summarize, Poweshiek skipperling was historically documented in 
4 sites in Wisconsin (Table 2). The species is considered to be present 
at one site and the occupancy is unknown at three sites (Table 2).
Manitoba
    Manitoba historically contained less than 1 percent (N=1) of all 
known records of Poweshiek skipperlings rangewide (Table 2); however, 
multiple Poweshiek skipperling historical records occur in one general 
location--a complex of several nearby small sites within the Tallgrass 
Prairie Preserve--in far southern Manitoba, near the United States 
border. Poweshiek skipperlings were first recorded in Canada near Vita, 
Manitoba, in 1985 at each of seven prairies surveyed, and populations 
were described as abundant but localized (Catling and Lafontaine 1986, 
p. 63). Poweshiek skipperlings were found at 15 of 18 locations 
surveyed within the same area in 2002 (COSEWIC 2003, p. 5).
    The Poweshiek skipperling is currently present at one location in 
Canada, The Nature Conservancy of Canada Tall Grass Prairie Preserve 
near Vita, Manitoba (Westwood 2010, p. 2; Westwood et al. 2012, p. 1; 
Hamel et al. 2013, p. 1). Poweshiek skipperlings were historically 
moderately common in areas of the preserve (Klassen et al. 1989, p. 
27). In 2002, Webster (2003, p. 5) counted approximately 150 
individuals, and in 2006, approximately 126 individuals were sighted 
across 10 sites (Westwood 2010, p. 3). Surveys of 10 sites in 2008 and 
2009 yielded 281 and 79 Poweshiek skipperlings, respectively (Dupont 
2010, pers. comm.). Poweshiek skipperling numbers in the preserve 
declined sharply after a 647-ha (1,600-ac) wildfire in fall 2009 burned 
much of the species' habitat, including areas that likely contained the 
largest and highest density populations (Westwood 2010, p. 2); surveys 
of comparable effort to the 2008 and 2009 surveys yielded only 13 
Poweshiek skipperlings on the preserve in 2010 (Westwood 2010, pp. 7-
22). Surveys of 45 sites within the Tall Grass Prairie Reserve during 
2011 resulted in 13 sites with positive sightings, 9 of which were new 
sites (Westwood et al. 2012, p. 11; Dupont 2011, pers. comm.). The 
average number of Poweshiek skipperlings found at each site ranged from 
10 to 15 per hour. These numbers are up considerably from 2010, but not 
as high as observed in 2008 (Dupont 2011, pers. comm.). In 2012, a 
total of 50 individuals were observed, which was ``low when compared to 
historic densities'' (Hamel et al. 2013, p. 17). Poweshiek skipperling 
sites in Manitoba are often surveyed up to 7 times during the flight 
period each year (Westwood 2013, pers. comm.). The preserve has 
detailed management recommendations to facilitate recovery of the 
Poweshiek skipperling (Westwood 2010, p. 5).
    Following an assessment and status report completed in 2003 under 
the Committee on the Status of Endangered Wildlife in Canada (COSEWIC), 
the Poweshiek skipperling was listed under the Species at Risk Act as 
Threatened in Canada in July 2005 (COSEWIC 2003). A recovery strategy 
is now in place for the species in Canada (Environment Canada 2012), 
which includes critical habitat designations within and adjacent to The 
Nature Conservancy of Canada Tall Grass Prairie Preserve (Environment 
Canada 2012, p. ii).

Summary of Comments and Recommendations

    In the proposed rule published on October 24, 2013 (78 FR 63574), 
we requested that all interested parties submit written comments on the 
proposal by December 23, 2013, during which we held public meetings on 
November 5, 2013, in Minot, North Dakota; November 6, 2013, in Milbank, 
South Dakota; November 7, 2013, in Milford, Iowa; November 13, 2013, in 
Holly, Michigan; and November 14, 2013, in Berlin, Wisconsin. We also 
contacted appropriate Federal and State agencies, scientific experts 
and organizations, and other interested parties and invited them to 
comment on the proposal. Newspaper notices inviting general public 
comment were published in the following papers: Detroit Free Press, 
Detroit, MI; The Detroit News, Detroit, MI; Berlin Journal, Berlin, WI; 
The Forum of Fargo-Moorhead, Fargo, ND; Minneapolis Star-Tribune, 
Minneapolis, MN; Mukwonago Chief, Mukwonago, WI; The Des Moines 
Register, Des Moines, IA; Bismark Tribune, Bismark, ND; The Argus 
Leader, Sioux Falls, SD. We did not receive any requests for a public 
hearing. All substantive information provided during comment periods 
has either been incorporated directly into this final determination or 
addressed below. Comments specific to the proposed designation of 
critical habitat for the two species (78 FR 63625) will

[[Page 63694]]

be addressed in the final critical habitat determination.

Peer Reviewer Comments

    In accordance with our peer review policy published on July 1, 1994 
(59 FR 34270), we solicited expert opinion from ten knowledgeable 
individuals with scientific expertise that included familiarity with 
the Dakota skipper or the Poweshiek skipperling and its habitat, 
biological needs, and threats. We received responses from seven of the 
peer reviewers.
    We reviewed all comments received from the peer reviewers for 
substantive issues and new information regarding the listing of the 
Dakota skipper or the Poweshiek skipperling. The peer reviewers 
generally concurred with our methods and conclusions and provided 
additional information, clarifications, and suggestions to improve the 
final rule. Peer reviewer comments are addressed in the following 
summary and incorporated into the final rule as appropriate.
General
    (1) Comment: Peer reviewers thought that the Service's 
interpretation of literature addressing threats to these species was 
well researched. However, some peer reviewers suggested that further 
research would strengthen or refine our understanding of these 
butterflies.
    Our Response: The Act requires us to make a determination on the 
status of species based on the best available information. However, we 
agree that that further studies of these species would further our 
understanding and help us with the recovery planning and 
implementation. We will consider further research needs in our recovery 
planning efforts.
    (2) Comment: One peer reviewer stated that, in the Executive 
Summary, the Service did not describe the effects of habitat management 
on butterflies, but rather focused on the impacts to native vegetation.
    Our Response: We have updated the executive summary to include the 
direct mortality that may occur due to management activities or natural 
occurrences. This subject is discussed in further detail in the 
Background section of this final listing rule.
Taxonomy
    (3) Comment: One peer reviewer provided a correction to the number 
of subfamilies in the family Hesperiidae and the number of species in 
the genus Hesperia. Specifically, the family comprises 7 subfamilies 
world-wide, 4 of which occur in North America, north of Mexico. There 
are 21 recognized species in the genus Hesperia (ibid), not 18 as cited 
in the proposal.
    Our Response: We corrected the statements in the Background section 
of this final listing rule.
Species Biology
    (4) Comment: One peer reviewer provided details on Dakota skipper 
and Poweshiek skipperling biology, specifically, information pertaining 
to early life stages and larval food choices, which were learned from 
captive-rearing trials at the Minnesota Zoo.
    Our Response: We have incorporated the updated information into the 
Background section of this final listing rule.
    (5) Comment: Two peer reviewers suggested that we incorporate the 
findings of two recently published Master's theses (Dupont 2013, Rigney 
2013a) that have new information on the Dakota skipper and Poweshiek 
skipperling, including data from surveys at several locations for both 
species in Manitoba. These studies also show a greater decline in both 
species in Canada over the last 10 years than is indicated in the 
proposed listing rule.
    Our Response: We incorporated data from the referenced Master's 
theses in the Dakota skipper Background section in this final listing 
rule. The new information, although important to our full understanding 
of the status of the species throughout their ranges, does not change 
our listing determinations for the two species.
    (6) Comment: A peer reviewer stated that based on personal 
observations and McAlpine's 1972 report, upon hatching, Poweshiek 
skipperling larvae crawl out near the tip of grasses, and do not crawl 
to the base of grasses, as was stated in the proposal.
    Our Response: We corrected the statement regarding Poweshiek 
skipperling larval behavior in the Background section of this final 
listing rule.
    (7) Comment: A peer reviewer noted that a species' nectar 
preference is usually indicated by selection in greater frequency 
rather than the proportion of the species among all available nectar 
sources (because random selection would be expected to result in 
selection frequency equal to the species' proportion of the available 
choices). All of the references cited in the rule report nectar 
preferences as the relative proportion among observed choices.
    Our Response: We clarified this point in the Background section of 
this final listing rule.
Food and Water
    (8) Comment: Peer reviewers provided corrections to the lists of 
flowers used as nectar sources and the importance of several plants as 
nectar sources for the butterflies.
    Our Response: We corrected the nectar flowers for Dakota skipper 
accordingly in the Background section of this final listing rule. Also, 
we removed upright prairie coneflower, fleabane, and white prairie 
clover from our list of important nectar species. We did not remove 
black-eyed Susan, because Rigney (2013a, p. 142) reported Dakota 
skippers were frequently observed nectaring on that species in Canada.
    (9) Comment: One peer reviewer stated that the assertion that 
Dakota skipper larvae feed only on native grasses has not been 
established, and further stated that when confined with no other 
choice, Dakota skipper larvae may feed on a variety of native and 
nonnative grasses. Exotic cool-season grasses, such as Kentucky 
bluegrass and smooth brome are available, and generally of good 
nutritional quality, when overwintering larvae emerge from hibernation 
and begin feeding. The tight empirical correlation between occurrence 
of this skipper and the dominance of native plants in the habitat, 
however, indicates that the species requires native grasses.
    Our Response: We have incorporated this information into the final 
listing rule, and recognize that Dakota skipper larvae can use both 
native and nonnative plants as food during certain stages of larval 
development. Some exotic cool-season grasses may be suitable larval 
food plants during limited times of larval development; however, the 
morphology and growth of these grasses may determine the suitability 
for the species, and if those grasses dominate a site, the chances for 
larvae finding suitable food sources is decreased.
    (10) Comment: One peer reviewer provided additional information on 
observations of Poweshiek skipperling oviposition and larval food use 
in Wisconsin.
    Our Response: We have incorporated the information into the 
Background section of this final listing rule.
    (11) Comment: One peer reviewer corrected our interpretation of his 
observations on Poweshiek skipperling oviposition (egg-laying) to state 
that larvae need to begin feeding on very fine, threadlike blade tips, 
and that females placed eggs on fine blade tips of grasses during some 
observed ovipositions.

[[Page 63695]]

    Our Response: We have incorporated this information into the 
Background section of this final listing rule.
    (12) Comment: One peer reviewer stated that the summary of the best 
available information for Dakota skipper dispersal is adequate and 
incorporates all of the information of which the reviewer is aware. The 
reviewer did correct our interpretation of Dana's 1997 mark-and-
recapture study. The reviewer stated that roads and crop-fields were 
suspected to be impediments to Dakota skipper movement; however, this 
was not explicitly tested during the study. Another reviewer wanted 
clarification on our basis for the estimated maximum dispersal distance 
of the Poweshiek skipperling.
    Our Response: We corrected the dispersal section of this final rule 
to accurately present Dana's 1997 mark-and-recapture study findings, 
and added information from an additional study. In one mark-and-
recapture study in Manitoba, the Poweshiek skipperling was found within 
50 m (165 ft) of its original capture location (Dupont 2013, p. 69). 
Besides this study in Manitoba, which had too few recaptures to make 
any statistically significant conclusions, we are unaware of any other 
dispersal studies for the species. Therefore, we used Dakota skipper 
(and dispersal studies on this species) as a surrogate species to 
estimate the maximum dispersal distance of the Poweshiek skipperling 
(e.g., Dana 1991, Dana 1997, Skadsen 1999a), and verified our 
assumptions with expert opinion and Burke (2011). Experts generally 
agreed that 1.6 km (1.0 mi) was a reasonable estimate for Poweshiek 
skipperling dispersal distance (Westwood 2012b, pers. comm.; Dana 
2012b, pers. comm.). However, according to Burke et al. (2011), the 
Poweshiek skipperling was less mobile than the Dakota skipper. Since 
experts generally assumed the maximum dispersal distance of the Dakota 
skipper was 1 km (0.6 mi), we used 1 km (0.6 mi) as a conservative 
maximum dispersal distance for the Poweshiek skipperling.
    (13) Comment: One peer reviewer questioned the accuracy of the 
mobility value assigned to the Dakota skipper from the Burke et al. 
(2011) publication. The reviewer suggested that the strongest evidence 
for limited dispersal capabilities is the absence of observations 
outside of native-prairie habitat. Butterflies that are highly mobile 
are occasionally observed in unsuitable habitat; however, factors such 
as the rarity of the species, its small size and inconspicuous 
appearance, and the rarity of observers that are both interested in 
skippers and capable of identifying them, makes the absence of 
observations in unsuitable habitats weak evidence for the absence of 
movement over long distances. The reviewer further stated that, since 
we have little basis for measuring dispersal in this species, but we 
have no evidence that it does much dispersing, we should assume that 
dispersal is very limited.
    Our Response: The Burke et al. (2011) paper was published in a 
peer-reviewed scientific journal (using expert interviews); however, we 
recognize the limitations of the data therein and, therefore, have 
arrived at our conclusion that the Dakota skipper has low dispersal 
capability based on this paper in conjunction with other reports and 
observations.
Habitat
    (14) Comment: One peer reviewer corrected the statement that Type B 
habitat (as explained in the Background section above) was the only 
habitat type inhabited by the Dakota skipper in Minnesota, as the 
species has been documented in other habitat types, particularly in 
Type A habitat in Kittson and Stearns Counties.
    Our Response: We corrected the statement regarding Dakota skipper 
habitat types in Minnesota in this final listing rule. It should be 
noted, however, that there is only one recent (2009) record of a Dakota 
skipper in Kittison County, Minnesota, and two sites in Stearns County 
where the species is possibly extirpated.
    (15) Comment: One peer reviewer stated that the assertion in our 
proposed rule that Dakota skipper larvae are ``particularly vulnerable 
to desiccation during dry summer months'' was a hypothesis, with no 
confirming evidence. The paper cited only surveyed occupied habitat and 
did not test unoccupied areas for the same parameters.
    Our Response: We realize the limitations of Royer's 2008 study, and 
have corrected our interpretations accordingly in this final rule; 
specifically, the sampling design (edaphic parameters were measured 
only in occupied areas, and no unoccupied areas were examined to test 
the significance of the findings) does not allow for statistically 
significant conclusions.
    (16) Comment: One peer reviewer corrected the definition given for 
``larval nesting zones'' measured for edaphic characteristics in Royer 
(2008). The ``primary larval nest zone'' in which they measured 
temperature and humidity is described as 0-2 cm above the soil surface, 
not between the soil surface and 2 cm deep as stated in the proposed 
rule.
    Our Response: We have corrected the statement regarding larval 
nesting zones in the Background section of this final rule.
Occupancy
    (17) Comment: Ane peer reviewer commented on the adequacy of the 
categorization of population status, and stated that it was done in an 
appropriately conservative way, but did not think this would affect the 
ultimate decision for either species
    Our Response: We developed the occupancy criteria to be as 
objective as possible in light of the information we had, which was 
complicated by the variability of the frequency and lack of error 
quantification of the survey data. We applied the occupancy rules 
consistently, in the same way throughout the range of each species, 
with discretion given to species experts who were familiar (e.g., who 
had conducted relatively recent site visits or butterfly surveys) with 
the sites within their State. Using the best information available, we 
attempted to balance our determination as to whether the species was 
likely present or not at a particular location. We determined that at 
sites where the species was detected during the most recent survey, if 
the survey was conducted in 2002 or more recently, this was a 
reasonable timeframe to assume its presence, if there was no evidence 
of habitat destruction or significant degradation of the habitat. Some 
other comments, however, indicated that the 10-year timeframe was too 
long to assume presence of an annual species, such as these 
butterflies, while others thought we should still be assuming presence 
at locations with detections much farther back (prior to 1993), if we 
had no evidence that the habitat hadn't been destroyed there. However, 
we believe that we have taken the most reasonable approach to defining 
occupancy, used the best available scientific information 
appropriately, and have been consistent in making this determination.
    (18) Comment: One peer reviewer noted that it would be useful to 
clarify the importance of unknown sites and to determine if habitat in 
``unknown'' sites, and sites where extirpation has presumed to have 
occurred, is actually in a condition to support future populations, 
particularly for future reintroductions.
    Our Response: It is important to distinguish among sites where the 
species is likely extirpated, where the species is still present, and 
where we are unsure of the species' presence, in

[[Page 63696]]

order to determine the current status of these species. The habitat at 
individual sites varies, but where we had evidence that the habitat was 
destroyed, we considered those sites to be extirpated (and, thus, 
unsuitable for future reintroductions). The habitat at other sites may 
still be suitable for one or both species, and its role in future 
recovery efforts, such as reintroductions, will be considered during 
the recovery planning and implementation phase for these species.
    (19) Comment: One peer reviewer requested that we define some terms 
used in the proposed rule; in particular, the terms ``positive 
detections,'' ``detection rate,'' and ``liv''.
    Our Response: Positive detections refers to the number of times the 
species was detected during a survey. Detection rate is calculated as 
the number of times the species was detected (at a singular site or 
groups of sites), divided by the number of surveys (at a singular site 
or groups of sites). Finally, ``liv'' refers to the page number in the 
preface of a cited publication (Roman numeral for page 54).
    (20) Comment: Does the definition of species extirpation from a 
site apply to surveys conducted in 1993, or to those done more 
recently?
    Our Response: We considered the species to be extirpated from a 
site if there were at least three sequential years of negative surveys, 
no matter the year those sites were surveyed, and the species has not 
subsequently been documented at the site. For example, if a site was 
only surveyed in 1991, 1995, and 1999, and there were no positive 
detections of the species during all 3 years, we assumed that the 
species is extirpated from that site. The species occupancy at that 
site would not change unless the species is detected at that site in 
the future. We have clarified this definition in the Background section 
of this final listing rule.
    (21) Comment: One peer reviewer wanted further clarification on our 
justification for including four Dakota skipper sites with older 
records in the present occupancy category. The reviewer suggested we 
review the previous densities of the species at the four sites and the 
proximity of nearby sites from which individuals could recolonize the 
sites in question.
    Our Response: The species occupancy at one of four South Dakota 
sites has been updated to ``unknown'' after further review of the 
information available for the site, including 2013 survey data that 
were not available to us at the time we drafted the proposed rule. 
However, there is no evidence to suggest that the species is not still 
present at the remaining three sites (all in Minnesota), because the 
best information indicates that the sites' habitats are still suitable 
for the butterfly, and, therefore, despite the lack of recent surveys, 
the species may still be present there.
    (22) Comment: A peer reviewer noted that at several points the 
proposed rule indicates that survey efforts may vary in number of 
visits, but that certain survey results were not considered, because 
they were not conducted at the appropriate time. The peer reviewer 
questioned whether we can presume that the surveys that were considered 
are comparable, regardless of the number of visits visits, whether 
those surveys all meet some minimum criteria, and whether there was a 
standard survey effort measurement.
    Our Response: Since the purpose of site surveys differed by site, 
the amount of effort also varied. For example, if the goal of the 
survey was to verify if the species was present at a particular 
location, a surveyor may have stopped the survey effort as soon as the 
first individual was detected, which may have occurred after a short, 
one-time visit. On the other hand, if the survey purpose was to count 
individuals during the peak flight of a species, the site may have been 
visited every day throughout the adult flight period, and more 
quantitative measurements, such as number of individuals observed per 
hour, may have been recorded. We used all types of surveys, as long as 
they were conducted during the appropriate time of the year (mid-June 
through mid- to late July), and during appropriate conditions (e.g., 
generally wind speeds less than 16 mph, unless the species was detected 
at higher speeds). Furthermore, we only considered surveys from 
individual surveyors who are able to reliably identify the species in 
the field.
    (23) Comment: A peer reviewer noted that the proposed rule states 
that existing models are unable to identify specific plant species, 
invasive species, and floristic quality, and the Service concludes that 
unbroken grasslands ``may not contain the specific native prairie 
plants that the Dakota skipper requires. . . .'' This statement appears 
to be contradicted later in the document.
    Our Response: We clarified the statements in this final listing 
rule. The intent of the first statement is to acknowledge that existing 
habitat models cannot identify specific species or determine floristic 
quality necessary to support Dakota skipper populations. The models may 
be useful in narrowing down areas that may contain the necessary nectar 
plants and larval food plants, but presence of specific plant species 
and suitability for the Dakota skipper must be verified by other means 
(e.g., on the ground plant surveys). The second statement refers to the 
possibility of yet undiscovered areas of suitable habitat where the 
Dakota skipper may exist, because not every area that is suitable has 
been surveyed for the species.
    (24) Comment: A peer reviewer noted that survey site selection may 
be influenced by the expert's knowledge of potential habitats, land 
ownership, and the ability to gain landowner permission to access areas 
for surveys.
    Our Response: We acknowledge that survey sites may be selected for 
a variety of reasons. A site may be surveyed because there is known 
suitable prairie habitat in an area, but the exact survey location may 
depend on other variables, such as the ability to gain landowner 
permission to survey.
Status and Trends
    (25) Comment: One peer reviewer provided additional 2009 data for 
the Felton Prairie site in Minnesota.
    Our Response: We incorporated this data into this final listing 
rule.
    (26) Comment: One peer reviewer requested clarification on the 
butterfly survey methodology and how floristic diversity was rated at 
some of the survey locations.
    Our Response: The survey methodology varied among locations, years, 
surveyors, and by other factors, and it is difficult to succinctly 
describe the methodology used for more than 20 years of surveys for 
hundreds of survey sites. For that reason, we examined the data in 
terms of the rate of positive detections over the years at each survey 
location as a way to compare data across multiple survey methods and 
years. We applied certain standards that each survey must meet (see 
response to comment 22, above). In this final listing, we describe 
survey methods or floristic quality determination methods for specific 
locations when it is necessary to understand the results for a 
particular survey, and describe typical survey and floristic 
methodologies in the Background section of this final rule.
    (27) Comment: A peer reviewer commented that the number of 
historical populations of Dakota skipper that remain extant is probably 
overestimated, given the results of recent resurvey efforts. In 
particular, this peer reviewer questioned whether it was realistic to 
assume species presence at five Minnesota sites, given the dramatic 
declines and apparent extirpation of populations at some of the

[[Page 63697]]

best sites within recent years. The reviewer suggested assigning those 
sites as ``possibly present'' or ``status unknown'' category, and 
targeting these sites for future surveys to determine the species' 
presence, particularly because recent declines do not appear to be due 
to habitat degradation or loss.
    Our Response: Based on 2013 survey data, we changed the occupancy 
for several sites. When determining species occupancy at a site, we 
balanced information on habitat succession with the available survey 
data to avoid falsely assuming the species is absent from less-surveyed 
sites that still have suitable habitat.
    (28) Comment: A peer reviewer commented that, based on surveys 
conducted in 2013, the status of both the Dakota skipper and the 
Poweshiek skipperling in Minnesota is likely more dire than suggested 
in the proposal. No Dakota skippers or Poweshiek skipperlings were 
observed during duplicate surveys conducted at 13 sites. During single 
surveys conducted later in the flight period (the time when adult 
butterflies are able to fly) at two additional sites in Clay County, 
MN, six Dakota skippers were seen at one of those sites and no 
Poweshiek skipperling were observed at either site. Both sites had 
fairly good numbers during 2008 surveys. Additionally, one peer 
reviewer suggested that we incorporate results from 2013 surveys of 
sites in Kittson County, Minnesota. No Dakota skippers were observed at 
Lake Bronson in 2013; however, there was one highly likely sighting, 
and the area contains moderate-quality habitat. The Frenchman's Bluff 
sites in Minnesota were surveyed on July 11, 2013, which was during the 
period of peak abundance in the phenologically (relationship between a 
periodic biological phenomenon and climatic conditions) delayed year, 
but the Dakota skipper was not observed. The estimated probability of 
the species presence at the site is 90 percent, based on the abundance 
of habitat and purple coneflower in bloom.
    Our Response: We incorporated the 2013 data into this final listing 
rule. Due to several negative results from 2013 surveys, particularly 
in Minnesota, the occupancy status at several sites has been updated in 
this final listing rule. We still determine that the Dakota skipper 
should be listed as threatened, and provide justification for our 
determination in this final listing rule.
    (29) Comment: One peer reviewer suggested that we incorporate 
information from a 2013 report of butterfly surveys in South Dakota.
    Our Response: We incorporated 2013 survey results in this final 
listing rule.
    (30) Comment: A peer reviewer suggested that the Dakota skipper 
population densities as described in 2003 and 2007 status assessments 
may no longer accurately describe the populations and the threats 
causing population declines. For example, reported sightings of Dakota 
skippers within the Riding Mountain National Park in Manitoba (Walleyn 
2002) are likely not valid; there are no voucher specimens to confirm 
the report. There are no known sites that are owned by the Government 
in Canada.
    Our Response: We incorporated updated information regarding several 
sites in Manitoba and Saskatchewan. We have no records of any confirmed 
Dakota skipper sites within the Riding Mountain National Park in 
Manitoba.
    (31) Comment: One peer reviewer noted that there has been a decline 
in the number of individual Dakota skippers observed during the flight 
period compared to the populations observed in 2002 and 2007. The 
current population estimates are much lower than those described in 
Webster's 2002 and 2007 reports. Furthermore, the methods for 
estimating densities have changed; survey methodology has become more 
rigorous, with 2 to 5 visits per site per year from 2009-2013 compared 
to single visits prior to 2008.
    Our Response: We incorporated 2013 data into this final listing 
rule. Due to largely negative results from 2013 surveys, the occupancy 
status of the species at several sites has been updated in this final 
listing rule.
    (32) Comment: One peer reviewer stated that there is a DuPage 
County, Illinois, record of a Poweshiek skipperling--the specimen was 
collected in 1968 near the DuPage River, and was only recently 
identified as a Poweshiek skipperling.
    Our Response: We have added the DuPage County record to the 
Illinois status and distribution section of this final listing rule.
    (33) Comment: One peer reviewer stated that, because no Poweshiek 
skipperlings were observed in 2013 at Scuppernong Scientific and 
Natural Area (SNA) in Wisconsin, nor at the nearby Wilton Road site, 
those populations may be extirpated. The peer reviewer also stated that 
the apparent decline in numbers was also observed in Michigan.
    Our Response: We have updated the Background section of this final 
listing rule to include the 2013 data for those two locations. Because 
there are just one or two years of negative data at the Scuppernong SNA 
and Wilton Road sites, the occupancy status at both sites is unknown.
    (34) Comment: A peer reviewer commented that the low numbers of 
Poweshiek skipperling observed in 2012 at Scuppernong SNA were at least 
partially due to the spring burns of 25-30 percent of their prime 
breeding habitat at that location. The range of variation of the 
maximum numbers observed in 2009-2012 may be skewed due to the low 
numbers observed in 2010, when the peak flight may have been missed due 
to an early flight and late survey effort. The anticipated increase in 
the population in 2012 due to a mild winter and early spring phenology 
was not observed, which may indicate that the burn killed a high number 
of larvae.
    Our Response: We clarified the statements regarding the uncertainty 
of the effect that the 2012 spring burn had on the Poweshiek 
skipperling population at that location. It is difficult to make cause-
and-effect statements without direct measures of larvae mortality 
following a burn.
    (35) Comment: A peer reviewer stated that the same protocol has 
been used for Poweshiek skipperling surveys in Wisconsin since the 
early 1990s--a modified Pollard transect count with a set transect 
pattern covering 6 ha (15 ac) of area and 40 minutes to complete.
    Our Response: We clarified the methodology used at the Scuppernong 
SNA sites in the Background section of this final listing rule.
Factors Affecting the Species
    (36) Comment: A peer reviewer suggested that it would be useful to 
rank or evaluate risks to the butterfly populations as they relate to 
management recommendations. For example, would haying carry a lower 
risk of causing extirpations? The level of risk, however, would depend 
on the type, duration, and timing of haying activities versus the type 
of fire management applied to sites.
    Our Response: Ranking management methods goes beyond the scope of 
this final listing document and is more appropriate for recovery 
planning. Furthermore, management recommendations may vary for each 
location, based on the habitat type and condition; therefore, it may 
not be possible to generalize the level of risk associated with various 
management types.
    (37) Comment: One peer reviewer commented on the level of private 
landowner awareness of the species and its status on their lands. 
Specifically, in Canada, most private landowners are unaware of the 
presence of the Dakota

[[Page 63698]]

skipper, and this may also be true for private landowners in the United 
States. Even where current management on lands may be conducive to the 
species, it is not typically due to a conscious effort to conserve the 
species. Landowner apathy should be considered a threat of considerable 
concern.
    Our Response: We agree that some landowners may not be aware of the 
presence of either butterfly on their lands and that land may not be 
intentionally managed for the conservation of the species, but rather 
used in ways that are inadvertently favorable to the species. We have 
discussed this issue further in Factor E of this final listing rule. In 
the United States, we have notified private landowners of most of the 
sites where we believe the species is still present or its status is 
unknown, and many of the sites where the species is extirpated or 
possibly extirpated, but where the habitat may still be suitable for 
the species. We will continue to focus on public awareness and work 
cooperatively with landowners following listing.
    (38) Comment: One peer reviewer asked for clarification on the 
reduction of Dakota skipper range, specifically what was meant by our 
statement of ``an approximately 690-km (430-mi) reduction of its 
range''
    Our Response: We have removed this phrase from this final listing 
rule, because it was unclear. The Dakota skipper is considered to be 
extirpated from Illinois and Iowa and no longer occurs in eastern 
Minnesota.
Factor A
    (39) Comment: One peer reviewer recommended that the date of first 
allowable haying be after July 22, because some adult flight has been 
documented after the date of July 16, which was our recommendation for 
the earliest haying. Another peer reviewer noted that in Manitoba, 
August 1 is the recommended earliest haying date at Dakota skipper and 
Poweshiek skipperling sites, although little haying is occurring where 
the Poweshiek skipperling is present. Sites should not be hayed within 
3 to 4 weeks of the beginning of the adult flight period to prevent 
destruction of nectar plants. While there may be situations in the 
United States where sites undergo haying ``no more than every other 
year,'' most sites in Manitoba are hayed for several years in a row, 
but there are no studies on the impact of repeat annual haying.
    Our Response: Our categorization of stressors as having high, 
medium, or low impacts on the species, and the criteria we use to 
define those categories, were developed specifically to guide our 
analysis of the factors affecting the species, and are not intended as 
guidelines for conservation efforts. Conservation guidelines for the 
Dakota skipper are available (online at http://www.fws.gov/midwest/endangered/insects/dask/DASKconservationguidelines.html), and we are 
developing similar guidelines for the Poweshiek skipperling. In those 
guidelines, we recommend that haying activities occur after the adult 
flight period.
    (40) Comment: A peer reviewer asked whether, in the grazing section 
of the proposed rule, did the Service mean that even when grazing is 
hard enough to eliminate the skipper, the habitat potential isn't 
completely destroyed, as it is by mining or plowing, and can be 
restored?
    Our Response: This is correct, and we clarified the language in 
this rule to more clearly state that, unlike habitat destroyed by 
mining or plowing, for example, intensely grazed habitat has potential 
to recover or be restored. Attempts have been made to restore prairie 
remnants that have been plowed or mined (where significant soil 
disturbance has occurred), but such restorations have not been 
successful for the Dakota skipper or Poweshiek skipperling, at least in 
observable timeframes.
    (41) Comment: A peer reviewer noted that the proposal asserts that 
``grazing is one of the primary treatments for controlling smooth brome 
and enhancing native plant diversity in prairies that have been invaded 
by this nonnative grass species.'' The peer reviewer stated that the 
assertion goes beyond anything in the cited document (Service 2006). 
There is no supporting research for grazing reducing brome, while at 
the same time maintaining or improving the native species composition. 
There is, however, support for the opposite--that grazing can stimulate 
brome and reduce native diversity. Smart et al. (2011) discuss grazing 
as a promising possibility, based on inferential, circumstantial, and 
anecdotal information, and the group agreed that experimental 
investigation is a big need. More accurately, the citation would 
support this statement: ``grazing may be a valuable tool for 
controlling smooth brome invasion and maintaining native diversity in 
prairies, especially where circumstances make the use of fire 
difficult.''
    Our Response: We clarified the statement regarding grazing as a 
potential management tool for invasive species control to more 
accurately reflect the proceedings of the Service workshop (Service 
2006) and Smart et al. (2011). Smart et al. (2011) used repeated 
clipping methods to simulate intensive early-season grazing and 
discusses the potential for using grazing as a tool to improve native 
prairie under certain conditions.
    (42) Comment: One peer reviewer said that recent statistics related 
to habitat conversion show that the statement, ``The economic benefit 
of grazing to ranchers may also benefit the species at some sites by 
deterring conversion of remnant prairies to row crop agriculture'' is 
out-of-date, and said this sentence contributes little to the argument 
that remaining habitat is secure.
    Our Response: We clarified the statement on conversion in this 
final rule to reflect the current economic conditions that row crop 
agriculture is generally more economically profitable than light 
grazing.
    (43) Comment: A peer reviewer noted that the proposed rule includes 
little discussion of soil compaction as a result of grazing. A field 
demonstration by Natural Resources Conservation Service (NRCS) staff 
showed that soil compaction on a heavily grazed pasture was almost as 
hard as a brick, and very little of the water falling on it soaked in. 
Soil of this character would be quite difficult for the larvae of 
Dakota skipper to penetrate for shelter construction, causing them to 
be more exposed to predators, parasitoids, and other environmental 
stresses. The Poweshiek skipperling would not be affected by 
compaction, as it doesn't burrow.
    Our Response: We agree that soil compaction due to heavy grazing 
may cause the Dakota skipper to be more exposed to predators, 
parasites, and other environmental stresses, such as fire, than if they 
were able to build underground shelters, and we have taken this into 
consideration in our evaluation of the threats to the species.
    (44) Comment: A peer reviewer commented that the effects of grazing 
in Manitoba and Saskatchewan, as stated in Webster (2007), may not be 
applicable under current population scenarios. Even light grazing may 
be detrimental on dry short-grass prairie sites prior to and during the 
adult flight period.
    Our Response: We incorporated this information into the Factor A 
threats analysis of this final listing rule, below.
    (45) Comment: A peer reviewer stated that potash mining, gravel 
mining, flooding, and associated flooding protection activities may be 
significant threats to these species in Canada.

[[Page 63699]]

    Our Response: We incorporated this information into the Factor A 
threats analysis of this final listing rule, below.
    (46) Comment: One peer reviewer recommended that we not include the 
research from an unpublished paper by Schlicht (2001a), due to serious 
flaws in the methodology.
    Our Response: Because of serious concern over the methods used in 
this unpublished paper, we removed the information from Schlicht 
(2001a) from this final listing rule (under Factor A--Fire), below.
    (47) Comment: A peer reviewer stated that the discussion on threats 
from fire in the proposed rule focuses on controlled burns, but 
wildfires are a serious problem in Manitoba and previously inhabited 
sites in northwestern Minnesota. Due to the highly fragmented nature 
and comparatively small size of sites, wildfire may be a greater threat 
than either haying or grazing activities.
    Our Response: We considered wildfires to have moderate to high 
impacts to Dakota skipper and Poweshiek skipperling populations; the 
impacts would depend on the timing, intensity, and extent of the burn. 
We discuss wildfires in Manitoba in the Background (population 
distribution and status) section and in Factor E of this final rule, 
and considered that fragmentation due to stochastic events, such as 
wildfires, may lead to extinction at isolated sites (Factor E).
    (48) Comment: One peer reviewer provided a link to the Northern 
Tallgrass Prairie Lepidoptera Conservation Conference Working Group 
Reports Synthesis.
    Our Response: We added the reference to the discussion regarding 
conservation efforts under Factor A in this final listing rule, below.
    (49) Comment: A peer reviewer noted that, in the Conservation 
Efforts To Reduce Habitat Destruction, Modification, or Curtailment of 
Its Range section of the proposed rule, there was reference to a 1995 
expert panel and plan. The peer reviewer asked whether an actual plan 
was developed.
    Our Response: The group outlined a plan for surveying populations 
and characterizing sites and habitats at priority areas, identifying 
and recommending management needs, monitoring, and outreach and 
education; however, this plan was not drafted or finalized.
    (50) Comment: A peer reviewer noted that, in a number of incidences 
within the last decade in Canada, sites have had general population 
declines or sites have been lost to intense agricultural use.
    Our Response: We are aware of four sites in Canada where the Dakota 
skipper is now extirpated or possibly extirpated due to habitat 
destruction. Only sites where we believed the species is currently 
present or possibly present (unknown) were evaluated in our threats 
assessment.
    (51) Comment: One peer reviewer provided details on Poweshiek 
skipperling populations following prescribed burns in Manitoba (based 
on Dupont 2013). Specifically, Poweshiek skipperling populations were 
most numerous in sites burned 5 to 8 years previously. The species was 
absent in sites that were burned the previous year, in small numbers in 
areas that were burned 2 to 4 years prior, and absent from areas that 
were burned 10 or more years before the survey.
    Our Response: We have incorporated this information under Factor A 
of this final listing rule, below.
Factor C
    (52) Comment: One peer reviewer provided additional information on 
Wolbachia, a bacteria affecting many butterfly species.
    Our Response: We incorporated the new information into our 
discussion on Wolbachia under Factor C of this final listing rule, 
below.
    (53) Comment: A peer reviewer commented that parasitism, predation, 
and disease may be significant stressors to Poweshiek skipperlings and 
Dakota skippers. A hypothesis in the rapid decline of the Poweshiek 
skipperling, and possibly the Dakota skipper, is that a newly virulent 
pathogen or a new parasitoid has increased mortality above normal 
levels. The small number of predation and parasitization events that 
were observed is evidence only of the difficultly in documenting such 
events. Dana (1991, pp. 26-27) reported observing predation on the 
butterfly by arthropods and large robber flies (Asilidae), which are 
common in upland prairie habitats. The peer reviewer also cited and 
discussed several studies that pertain to predation on butterflies.
    Our Response: We reviewed the McCabe (1981) and Dana (1991) reports 
again and considered additional information on the normal population 
dynamics of insects, how these factors may explain the rapid decline of 
the Poweshiek skipperling, and perhaps the Dakota skipper, and how 
these factors may affect small, isolated populations in the future. We 
cannot conclude with certainty that parasitism and predation are 
significant stressors, because these occurrences are extremely 
difficult to observe, and only a few studies document these events. 
Therefore, we conclude that the level of impact from disease, 
parasitism, and predation is uncertain, but do not dismiss the 
possibility that these factors may become significant in the future.
Factor D
    (54) Comment: A peer reviewer commented that, in North Dakota, the 
fundamental purpose of management of State School lands is economic, 
not scientific or environmental. Consequently, if such land does not 
produce income for the State, it may be subjected to deliberate change 
in management strategy, including sale at auction. The Dakota skipper's 
security at no fewer than two sites in North Dakota, therefore, depends 
on the economic value of hay, because those sites are on North Dakota 
Trustlands and are currently under haying management.
    Our Response: We have incorporated this information into Factor D 
of this final listing rule.
    (55) Comment: A peer reviewer stated that the Poweshiek skipperling 
was listed as State-endangered in Minnesota on August 19, 2013.
    Our Response: We have updated the State status of the Poweshiek 
skipperling in Minnesota in this final rule.
Factor E
    (56) Comment: One peer reviewer stated that, although the Service 
has not collected much direct evidence of threats to populations of the 
Poweshiek skipperling in North Dakota compared to Dakota skippers in 
the State, it is reasonable to assume that the same factors that affect 
the Dakota skipper have similarly affected the Poweshiek skipperling, 
because the two species share a preponderance of habitat 
characteristics, and often are sympatric (have overlapping ranges).
    Our Response: The Service agrees with the reviewer's statement. We 
also think that the reverse is true: It is reasonable to assume that 
Dakota skipper may be vulnerable to the factors that have caused 
dramatic declines in the Poweshiek skipperling, but perhaps with a 
delay in timing. We consider this possibility in our analysis.
    (57) Comment: One peer reviewer provided detailed information on 
the size and isolation of Dakota skipper sites in central Manitoba. 
These sites are generally greater than 158 ac (64 ha), and all are 
separated by 1 km (0.6 mi). Several sites are separated by many 
kilometers (miles). The reviewer also suggested that the Service 
consider the implications of the separation of the U.S. and Canada 
sites.

[[Page 63700]]

    Our Response: We have incorporated this information, supplemented 
by information in two recently published Master's theses (Dupont 2013, 
Rigney 2013a), to update our threats analysis for Canadian populations. 
Although we were unsure of the size of many sites in Canada, most sites 
were separated by more than 1 km (0.6 mi); therefore, approximately 25 
of the sites evaluated in Canada were thought to be at least moderately 
affected by small size and isolation. The Canada sites where Dakota 
skippers are considered to be present are approximately 115 km (71 mi) 
from the nearest U.S. sites, and the Manitoba site is approximately 166 
km (103 mi) from the nearest Poweshiek skipperling site in Minnesota.
    (58) Comment: A peer reviewer noted that South Dakota State 
University conducted a climate change analysis, with an emphasis on 
terrestrial habitats, in association with the revision of the South 
Dakota Wildlife Action Plan.
    Our Response: We reviewed that report and incorporated relevant 
information into Factor E of this final listing rule. We will also 
consider this report during recovery planning for the two species.
    (59) Comment: One peer reviewer queried as to whether either 
species has been evaluated using NatureServe's Climate Change 
Vulnerability Index (https://connect.natureserve.org/science/climate-change/ccvi)?
    Our Response: The Service has not evaluated either species using 
NatureServe's Climate Change Vulnerability Index, but will consider 
using this tool in the recovery phase. We used several studies specific 
to the Dakota skipper and Poweshiek skipperling, as well as general 
studies of climate-related changes in the Midwest and throughout North 
America. See the Climate Change section of this final rule for more 
details on the studies used.
    (60) Comment: A peer reviewer suggested that the Service should 
provide more detail on the need for future planning, potential 
dispersal corridors, restoration of existing sites, and potential 
reintroduction and augmentation sites. The high degree of habitat 
fragmentation and isolation of sites combined with the limited 
dispersal ability of these species have potential for long-term 
implications, and management actions, even if effective in short-term 
conservation of local populations, may not be enough to prevent the 
species from extirpation.
    Our Response: We agree with the peer reviewer that detailed 
planning will be needed to recover the Dakota skipper and Poweshiek 
skipperling. The Service will begin the recovery planning process once 
the final listing becomes effective.
    (61) Comment: One peer reviewer wanted to know how the species 
would be treated for law enforcement purposes, in order to ensure that 
private landowners and others that may have these species on their land 
would comply with section 9 of the Act. The reviewer asked specifically 
about unauthorized collection, handling, and possession that could 
result in a violation of section 9 of the Act, as listed in the 
``Available Conservation Measures'' section of the proposed listing 
rule. The reviewer stated that it may be likely that private citizens 
have specimens of these species in their possession.
    Our Response: If private citizens hold specimens of either species 
that have been collected in the past, they should report these 
specimens to their local conservation officer or Service enforcement 
official to receive the appropriate documentation that they were 
collected prior to listing. Collecting either the Dakota skipper or 
Poweshiek skipperling after they are listed would be a violation of 
section 9 of the Act, unless the collector held an appropriate permit 
from the Service.
    (62) Comment: One peer reviewer noted that the list of nonnative 
species in the ``Available Conservation Measures'' section of the 
proposed listing rule are already well-established species. A more 
meaningful list would include species that are not already established, 
to prevent future invasive species issues that negatively impact these 
and other native species, and that would inform land managers of plant 
selection for grassland or wildlife-related plantings.
    Our Response: We agree that glossy buckthorn, reed canary grass, 
and leafy spurge are well established in many areas within the range of 
the species. It is still important for landowners to know that these 
nonnative species are detrimental to the butterflies and their habitat, 
so they may avoid introducing them to additional areas or conduct 
activities that would spread their growth. We added purple loosestrife 
to the list of invasive plants as well. Purposeful introductions of any 
of the above species would be detrimental to the butterflies and their 
habitats. This list is not exhaustive, and other nonnative species may 
be destructive to the butterflies or their habitats.
    (63) Comment: A peer reviewer asked how the habitats in which the 
Poweshiek skipperling or Dakota skipper is known to occur will be 
defined, and whether that information will be available to the public, 
such that landowners can comply with section 9 of the Act.
    Our Response: The Service maintains a list of counties that are 
within the current range of the species on publicly accessible Web 
sites. We suggest that project proponents contact their State's U.S. 
Fish and Wildlife Service Ecological Services Field Office for specific 
information on their area. The species are likely to be present only in 
areas with suitable native-prairie habitat, and may be present in 
nearby grass-dominated areas suitable for dispersal during the adult 
flight period. Suitable habitats are further described in the 
Background section of this final listing rule.
4(d) Rule
    (64) Comment: A peer reviewer suggested that the 4(d) rule should 
exempt take caused by haying only after July 22, because the Dakota 
skipper flight period extends until after July 15 at some sites in some 
years.
    Our Response: We acknowledge that extending the earliest date of 
haying from July 15 to July 22 may further minimize the likelihood of 
adverse effects to the Dakota skipper, but we will retain the July 15 
date for the following reasons: First, factors other than the date in 
the 4(d) rule will likely play a greater role in determining actual 
haying dates, and those factors are likely to cause much of the haying 
conducted in areas where the Dakota skipper occurs to be carried out 
later than the July 22 date suggested by the commenter. Second, the 
July 15 date has been used for many years in a variety of conservation 
agreements as a date to ensure that the effects of haying on nesting 
birds is minimized. It is typically included, for example, as a 
required provision in grassland conservation easements purchased on 
private lands by the Service. By retaining the July 15 date, we 
minimize the likelihood of causing confusion, and encourage greater 
cooperation with our conservation partners. Third, even if haying is 
conducted immediately after July 15, it may be sufficient to minimize 
adverse effects to Dakota skippers at most sites and in most years. 
Moreover, in years when the flight period is ongoing past July 15, the 
Service can work voluntarily with landowners and land managers to delay 
haying until the flight period is over.

Comments From Federal Agencies

    (65) Comment: The National Guard in North Dakota (NDARNG) commented 
on their concern that training activities on the Camp Grafton South 
(CGS) and Garrison Training Area (GTA) will be

[[Page 63701]]

restricted and that the NDARNG would be overwhelmed with new permitting 
and reporting requirements due to the listing of the Dakota skipper. 
The NDARNG requested that either State-owned or federally-owned land 
that is operated and managed by the NDARNG be exempt from these 
proposed rules per proposed Sec.  17.47(b)(3) for military training 
conducted on lands covered under an Integrated Natural Resources 
Management Plan (INRMP).
    Our Response: Neither the CGS nor the GTA was included in the 
proposed critical habitat designation. However, according to section 
4(b)(B)(iii) of the Act, the Department of Defense must still comply 
with section 9 of the Act, including the prohibition preventing 
extinction and taking of endangered species and threatened species.
    (66) Comment: The NDARNG provided additional reports by Fauske for 
surveys conducted in the CGS and GTA in 2003 and 2004. The National 
Guard also mentioned surveys that were conducted by Fauske in 2013 at 
those locations. Dakota skipper was not observed at those sites in 
those years.
    Our Response: We incorporated the data from the 2003 and 2004 
reports into this final listing rule. We have not been able to obtain 
the data from Fauske's 2013 surveys, but did incorporate the National 
Guard's claim of negative surveys in 2013 into this final listing rule.
    (67) Comment: One commenter stated that two publications (Grant et 
al. 2009, DeKeyser et al. 2009) that discuss management of prairies 
show that sometimes prescriptions for long-term management of habitat 
are at odds with short-term management of the species. For example, no 
or light grazing or late-season haying may lead to invasion of cool-
season exotic grasses and loss of native forb and grasses. Thus no 
management could sometimes be considered a threat, just as prairie 
conversion may cause take.
    Our Response: We agree that no management or lack of disturbance 
may be a threat to Dakota skipper and Poweshiek skipperling habitat and 
that haying, grazing, and fire may be an important management tool for 
these butterflies, if carried out appropriately. These topics are 
discussed further in Factor A in this final listing rule, below. 
Adaptive management may be necessary at many locations to take into 
account the underlying causes of habitat degradation and the long-term 
and short-term consequences of management to the habitat and the 
species. We will be addressing management at specific locations during 
recovery planning for both species.
    (68) Comment: A Federal agency commented that some native-prairie 
plant species decrease without proper grazing management, and long-term 
monitoring is needed to properly examine plant species declines. 
Furthermore, plant species declines may be due to other factors, such 
as landscape position, climatic factors, historical and current 
management, and other ecological site conditions. Several papers cited 
in the proposed rule incorrectly identify forb species that decrease 
due to grazing, such as the purple coneflower.
    Our Response: We acknowledge that long-term monitoring data would 
be a valuable indicator of important plant species declines. 
Unfortunately, we do not have long-term monitoring established at most 
sites; therefore, we must rely on the best information available. Most 
references to grazing impacts on prairie butterflies are based on 
ancillary observations made during research focused on other management 
impacts. Some of these may be observational data of changes in site 
conditions at a particular site from one year to the next following 
changes in management regimes. We cite a few studies that show that 
certain levels of grazing remove nectar sources and are, therefore, 
likely to adversely affect Dakota skipper populations (e.g., Rigney 
2013a, pp. 143, 153). We discuss grazing, including the effects of 
grazing management in different habitat types, further in Factor A of 
this final listing rule, below.
    (69) Comment: A Federal agency noted that the proposed listing rule 
states that a large portion of the Dakota skipper habitat should remain 
ungrazed or lightly grazed during the adult flight period. Management 
focused on preserving every life stage of the butterflies will actually 
lead to their demise by inadvertently destroying their habitat.
    Our Response: Britten and Glasford (2002) recommend minimizing 
disturbance of Dakota skipper habitat during the flight period (late 
June to early July) to maximize genetically effective population sizes 
(the number of adults reproducing), to offset the effects of genetic 
drift of small populations (change in gene frequency over time due to 
random sampling or chance, rather than natural selection). All life 
stages are essential to the survival of the species, including the 
adult flight stage, which is when breeding occurs. Removal of important 
nectar sources during the short adult flight period can adversely 
affect the Dakota skipper (e.g., Rigney 2013a, pp. 143, 153). Thus, it 
is equally important to minimize disturbance of Poweshiek skipperling 
habitat during their adult flight period for the same reasons.
    (70) Comment: A Federal agency noted that Britten and Glasford 
(2002, p. 373), cited in the proposed rule, does not identify grazing 
as a disturbance, as the proposed rule indicates.
    Our Response: Although Britten and Glasford (2002) did not 
specifically identify grazing as a disturbance, other information 
sources indicate that grazing can disturb adult Dakota skippers and 
Poweshiek skipperlings, because it may remove important nectar sources 
(e.g., Rigney 2013a, pp. 143, 153). Both the beneficial and negative 
effects of grazing are further discussed in Factor A of this final 
listing rule, below.

Comments From States

    (71) Comment: A State commented that a comprehensive survey effort 
throughout the range of the two species is prudent, if not necessary, 
before any listing can occur.
    Our Response: Under the Act, we are obligated to use the best 
available scientific and commercial information in decisions on whether 
to list a species. In this case, the best available information 
included results from surveys, reports by scientists and biological 
consultants, natural heritage data, and expert opinion from biologists 
with extensive experience studying the Dakota skippers and Poweshiek 
skipperling and their habitats, whether published or unpublished. We 
are required to make a decision based on that available data. Also, see 
response to comment 76.
    (72) Comment: The Minnesota Department of Natural Resources (MN 
DNR) agrees with the Service's conclusion that these species warrant 
protection under the Act and fully supports the proposed threatened 
status for the Dakota skipper and the proposed endangered status for 
the Poweshiek skipperling. The MN DNR has a long history of commitment 
to the conservation of these species and has been an active participant 
in recent efforts to assess their status in Minnesota. The MN DNR 
agrees with the Service's conclusions regarding factors affecting the 
species and their resulting status. In light of recent findings, the MN 
DNR has reclassified both species as endangered under Minnesota's 
Endangered Species Statute, effective August 19, 2013.
    Our Response: We appreciate our partnership with MN DNR and their 
supporting comments, and have updated the information regarding the 
reclassification of both species under

[[Page 63702]]

Minnesota's Endangered Species Statute in Factor D of this final 
listing rule.
Habitat
    (73) Comment: The North Dakota Game and Fish Department suggests 
that the Service use NRCS Ecological Sites of North Dakota as a means 
to describe specific potential habitat, rather than Type A and Type B 
habitat as described in the proposed rule. The ecological site 
descriptions and transition models would help direct the proper grazing 
prescription to promote and achieve the plant species composition 
appropriate for the given site and requisites for these two butterfly 
species.
    Our Response: We are considering using NRCS ecological site 
descriptions as a tool for managers and others to narrow down potential 
habitat for one or both species. However, NRCS ecological site 
descriptions have not been developed for all areas where the species 
may be present. For the purposes of this final listing, we found that 
Type A and Type B habitat descriptions were descriptive of the habitat 
and flowering forbs and grasses necessary for the two butterflies.
    (74) Comment: North Dakota commented that, based on the specific 
precipitation and evaporation rates of Dakota skipper habitat that 
McCabe suggests, the western area of North Dakota should not be 
considered as part of the range for the Dakota skipper, as those areas 
do not meet those specific rates.
    Our Response: We have determined that the Dakota skipper is 
threatened throughout its range, which includes the 18 counties where 
the species has been documented in North Dakota. The Dakota skipper is 
historically known from several counties in western North Dakota (e.g., 
McKenzie, Burke, Montrail, and Dunn counties) and is considered to be 
present in at least two locations in McKenzie County. The Dakota 
skipper may still occur in areas of western North Dakota that may have 
conditions that are different from what McCabe (1981) describes for 
some of the eastern counties. See the Background section of this final 
listing rule for a list of counties in each State.
    (75) Comment: North Dakota commented that it appears that any 
native grassland in North Dakota that has not been cultivated is 
potential Dakota skipper habitat.
    Our Response: To more clearly define what constitutes Dakota 
Skipper habitat and where take of Dakota skippers may occur, the 
Service developed tools to help determine whether the species may be 
present in specific areas, which are available on the Internet at 
https://www.fws.gov/midwest/Endangered/section7/s7process/s7guid_cons.html#dask. We will continue to refine these materials to 
help reduce uncertainty as to where Dakota skippers may occur. Dakota 
skippers are present on only a subset of native grassland and are 
unlikely to be present in areas where key habitat features are lacking. 
Those features are described in the Background section of this rule and 
in the materials available on the Internet. As we work to conserve 
Dakota skippers, we will provide landowners and land managers with 
information that is as accurate and up-to-date as possible to describe 
the areas where the species is likely to be present. In addition, we 
will also work with these parties to ensure that they understand what 
activities are likely to cause take of the species, whether or not the 
take would be exempted under the 4(d) rule, and what actions may be 
implemented to conserve the species.
Population Status and Distribution
    (76) Comment: A State commented that surveys appear to be focused 
on repeated visits to sites that were previously inventoried, and a 
systematic search for additional sites has not been conducted. 
Furthermore, a few new sites have been discovered since 1996 without 
such a systematic search for new sites, which suggests that many new 
sites may be found with a systematic search. Additionally, roadside 
searches for habitat are not a scientifically valid method for 
identifying potential habitat.
    Our Response: The search for additional locations of both species 
has been conducted using a variety of approaches over the years, and 
potential sites have been narrowed down on the landscape using 
topographic and aerial maps, State natural heritage habitat mapping 
data, aerial surveys, roadside surveys, and other methods. Other sites 
have been surveyed because of a proposed project and the known 
potential for suitable habitat in the area or proximity to other known 
locations of the butterflies. Many sites are repeatedly surveyed to 
understand long-term trends in the presence of the species or to 
quantify other population parameters. Although only a small fraction of 
all grassland in North Dakota, South Dakota, and Minnesota has been 
surveyed, a significant proportion of the un-surveyed area is likely 
not suitable for the species. For example, the species was not detected 
at approximately 108 additional locations in North Dakota that were 
surveyed for the species in the period 1991-2013 (USFWS 2014, unpubl. 
geodatabase). Similarly, in South Dakota and Minnesota, 79 and 148 
additional locations, respectively, were surveyed for the species in 
the period 1991-2013 (USFWS 2014, unpubl. geodatabase).
    Many of these sites have been surveyed multiple times over several 
years. Surveys for the Dakota skipper are typically conducted only in 
areas that have the particular plant species the skipper requires. New 
potential sites surveyed are generally focused on prairie habitat that 
appears suitable for the species and has a good potential of hosting 
the species. Therefore, researchers have a higher likelihood of 
detecting the species at these sites than at sites randomly selected 
across the landscape. Based on these surveys, the likelihood that 
significant numbers of undiscovered Dakota skipper populations occur in 
North Dakota, South Dakota, or Minnesota is low. We acknowledge that 
there may be some undiscovered populations, however, and are exploring 
using spatially explicit modeling to develop probability occurrence 
maps of both species, to help direct future surveys and conservation 
efforts.
    (77) Comment: Since the Poweshiek skipperling has not been detected 
in South Dakota since 2002, South Dakota should not be included in the 
listing proposal. Further research needs to be conducted to determine 
if this species is present in South Dakota before it is listed.
    Our Response: According to our data and analysis, the species' 
presence is unknown at 36 of the total 69 sites where the species has 
been documented in South Dakota. The species was detected at least once 
at all 36 of these sites in 1993 or later; 19 of these sites had 
positive detections of the species in 2002 or later. The most recent 
detection of the species in South Dakota was at two sites in 2008. 
Surveys for the species were not conducted at any of the 36 sites with 
unknown occupancy between the years 2007 and 2011, and we cannot 
presume that the species is not persisting at a site only because there 
have not been consistent annual surveys. At several sites, the species 
has persisted for longer than 20 years; for example, the Dakota skipper 
was first recorded at Scarlet Fawn Prairie in South Dakota in 1985 and 
the species was detected during every survey since that date. 
Similarly, the Poweshiek skipperling was first recorded at Waubay 
National Wildlife Refuge in 1969 and was recorded during every year the 
site was surveyed through 2003. South Dakota is in the range of the 
Poweshiek skipperling, and the species is listed throughout its range. 
See our

[[Page 63703]]

response to comment 76 regarding additional surveys or research.
Factor A
    (78) Comment: A State commented that careful implementation of 
grazing and prescribed fire can be an effective management tool in 
prairie remnants. The Service should provide clear and practical HMGs/
BMPs (Habitat Management Guidelines/Best Management Practices) for 
acceptable use of prescribed fire and grazing implementation.
    Our Response: We developed Dakota skipper conservation guidelines 
(http://www.fws.gov/midwest/endangered/insects/dask/DASKconservationguidelines.html) that address grazing, prescribed fire, 
weed/invasive species control, and other topics, and are preparing 
similar guidelines for the Poweshiek skipperling. While some detail is 
provided in terms of timing, periods of rest, and number and size of 
burn units, the Service stresses that effective implementation of the 
conservation measures relies on a thorough and accurate understanding 
of the distribution and status of the Dakota skipper and Poweshiek 
skipperling and their habitat within a management area. These two 
species are likely to be non-uniformly distributed within habitat areas 
(e.g., Rigney 2013a, p. 140). Therefore, a species expert should 
frequently assess and map habitat and distribution of the species 
within management areas to ensure that managers may act based on 
correct and up-to-date information.
    (79) Comment: A State asked whether grazing of potential butterfly 
habitat other than low mesic sites will constitute take.
    Our Response: Such decisions will require site-specific 
information. If a project occurring in potential butterfly habitat may 
affect one or both species or its habitat, we suggest contacting the 
Service's Ecological Service Office in your State.
    (80) Comment: A State commented that habitat modification and 
fragmentation may be a large threat to many grassland species. While 
other factors may need to be addressed to protect the species, 
conversion of grasslands is the largest single issue. Once land 
conversions have occurred, the land cannot be restored to match the 
specific requirements of these specialist species. Listing can be 
viewed by private landowners as an encumbrance and a disincentive to 
conserve grassland; hence privately owned grassland could be converted, 
due to the current crop commodity environment and demand for additional 
cropland.
    Our Response: We agree that conversion of remnant prairies is a 
significant concern. Conversion of land to agricultural and other uses 
is discussed in Factor A of this final listing rule, below.
Factor E
    (81) Comment: South Dakota commented that, as part of the South 
Dakota Wildlife Action Plan Revision, experts at South Dakota State 
University conducted a climate change analysis with an emphasis on 
terrestrial habitats.
    Our Response: The Service appreciates this information. We reviewed 
the climate report and included information from it into Factor E of 
this final listing rule. This report will also help inform recovery 
planning and implementation.
Economic Concerns
    (82) Comment: A State questioned how a private landowner would be 
compensated if, during the course of the Service's activities for 
monitoring the critical habitat areas, the private landowner's land or 
property is damaged.
    Our Response: Surveys for either species on private lands would 
only be conducted with landowner permission. Surveys for the species 
and its habitat are not destructive in nature and have little, if any, 
impact on the land.
    (83) Comment: North Dakota commented that listing these two species 
will add a substantial workload relative to highway improvement project 
development, construction, and maintenance, due to additional section 7 
consultations with the Service. This increased workload could add 
months to project timelines and would cause a major and unnecessary 
disruption to the highway and road systems in North Dakota.
    Our Response: Although an increased workload for section 7 
consultations may be associated with listing these two species, section 
4 of the Act requires species to be listed as endangered or threatened 
solely on the basis of their biological status and threats to their 
existence. Section 7 of the Act requires Federal agencies to use their 
legal authorities to promote the conservation purposes of the Act and 
to consult with the Service to ensure that effects of actions they 
authorize, fund, or carry out are not likely to jeopardize the 
continued existence of listed species. During consultation, the action 
agency receives a biological opinion or concurrence letter addressing 
the proposed action. In the relatively few cases in which the Service 
makes a jeopardy determination, the agency offers reasonable and 
prudent alternatives for how the proposed action could be modified to 
avoid jeopardy. The Service will work with the consulting agency as 
expeditiously as possible to complete the section 7 consulation process 
in a timely manner.
    (84) Comment: A State asked, what would happen should a private 
landowner incidentally take either species during the course of routine 
farming operations on private land.
    Our Response: Under the Act, it is unlawful for a person to take a 
listed animal without a permit. Take is defined as ``harass, harm, 
pursue, hunt, shoot, wound, kill, trap, capture, or collect or attempt 
to engage in any such conduct.'' Through regulations, the term ``harm'' 
is defined as ``an act which actually kills or injures wildlife. Such 
an act may include significant habitat modification or degradation 
where it actually kills or injures wildlife by significantly impairing 
essential behavioral patterns, including breeding, feeding, or 
sheltering.'' Section 10 of the Act may be used by landowners including 
private citizens, corporations, Tribes, States, and counties who want 
to develop property inhabited by listed species. Landowners may receive 
a permit to take such species incidentally to otherwise legal 
activities, provided they have developed an approved habitat 
conservation plan (HCP). HCPs include an assessment of the likely 
impacts on the species from the proposed action, the steps that the 
permit holder will take to avoid, minimize, and mitigate the impacts, 
and the funding available to carry out the steps. HCPs may benefit both 
landowners and the species by securing and managing important habitat, 
and by addressing economic development with a focus on species 
conservation.
    We recognize that the Dakota skipper and Poweshiek skipperling 
remain only on lands where management has allowed them to survive. This 
is due to good land-stewardship, and we want to encourage management 
practices that support the butterflies. To minimize impacts to 
landowners and promote continued cooperation with them while recovering 
the Dakota skipper, the Service developed a 4(d) rule under the Act for 
that species. This 4(d) rule exempts incidental take of Dakota skippers 
caused by certain routine livestock operations and mowing recreational 
trails. Any ``take'' that results from private landowner activities not 
exempted under the 4(d) rule would require a permit from the Service. 
Therefore, private landowners with

[[Page 63704]]

Dakota skippers on their property should become familiar with the 
contents of the 4(d) rule and contact the Service if they have 
questions. Actions that may cause ``take'' and require a permit from 
the Service include prescribed burns, haying before the adult flight 
period ends, broadcast herbicide treatments, some insecticide 
treatments, and permanent conversion of the Dakota skipper's grassland 
habitats. The 4(d) rule does not apply to take of the Poweshiek 
skipperling because it is listed as endangered, and the Act does not 
allow 4(d) rules for endangered species. Any activity that would result 
in take of Poweshiek skipperlings would first require a permit from the 
Service.
    (85) Comment: A State commented that where section 7 consultations 
will be required is unclear. What areas would have to be surveyed to 
determine whether the species is present? A large amount of potential 
habitat may need to be surveyed during the short adult flight period, 
and there are a limited number of qualified entomologists to conduct 
the surveys.
    Our Response: The Dakota skipper and the Poweshiek skipperling are 
both closely tied to native-prairie habitats and are unable to inhabit 
areas such as nonnative grasslands, weedy roadsides, or tame haylands. 
In addition, these butterflies are not likely to inhabit reconstructed 
prairies (e.g., former cropland replanted to native-prairie species). 
Therefore, the Service recommends that, to determine whether a section 
7 consultation may be required or recommended, action agencies should 
first coordinate with their local U.S. Fish and Wildlife Service 
Ecological Services field office and provide a description of the area 
that would be affected, directly or indirectly, by the proposed or 
ongoing action. If survey data are unavailable or inconclusive for the 
action area, and features of Dakota skipper or Poweshiek skipperling 
habitat are predominant in at least part of the area, a survey by a 
qualified individual may be recommended. The Service is developing a 
list of qualified surveyors, which will be available through the field 
offices in each State.
    (86) Comment: North Dakota expressed concern that any impact to 
native grasslands in North Dakota will be considered take and require 
an incidental take permit. Adjusting the timing of construction 
activities will not avoid take because of the species' biology.
    Our Response: The Dakota skipper and Poweshiek skipperling 
historically occurred in 18 and 7 counties in North Dakota, 
respectively, and unless the species are discovered in additional 
counties, section 7 consultation would be required only in those 
counties and on a subset of lands within those counties where the 
species may occur or where critical habitat has been designated. You 
may obtain a list of counties in which the species may occur from the 
U.S. Fish and Wildlife Service Ecological Services field office in your 
State. Furthermore, these two species have specific habitat 
requirements (native, unbroken prairies), and it is likely that many 
action areas will not contain those types of prairie habitats. 
Therefore, project proponents should first provide the field office 
with a description of the area that would be affected by the proposed 
or ongoing action to determine whether a section 7 consultation may be 
required or recommended. See our response to comment 85 and the 
Background of this final listing rule for additional information 
regarding the habitats these two species inhabit.
    (87) Comment: A State asked whether reinitiation under section 7 of 
the Act will need to occur, or will any new restrictions be recommended 
when new projects begin or existing projects are renewed.
    Our Response: Section 7(a)(2) of the Act requires Federal agencies 
to consult with the Service to ensure that actions they fund, 
authorize, permit, or otherwise carry out will not jeopardize the 
continued existence of any listed species or adversely modify 
designated critical habitat. Therefore, reinitiation of section 7 
consultations may be required for ongoing, new, or revised actions that 
may affect the Dakota skipper or Poweshiek skipperling or their 
designated critical habitat. We recommend contacting the U.S. Fish and 
Wildlife Service Ecological Services field office in your State to 
determine the need for section 7 consultations on specific projects.
    (88) Comment: A State asked what types of conservation or 
mitigation measures would be needed to offset potential impacts to the 
species or designated critical habitat, and how will the Service ensure 
timely approval of mitigation measures.
    Our Response: The Service developed conservation guidelines for the 
Dakota skipper that are available online (http://www.fws.gov/midwest/endangered/insects/dask/DASKconservationguidelines.html) and is 
developing similar guidelines for the Poweshiek skipperling. We suggest 
that private landowners implement applicable guidelines to assist 
species and habitat conservation efforts and contact their local 
Service Ecological Services field office if they are planning an 
activity that may affect one of these species. For actions with a 
Federal nexus, action agencies should contact their local field office 
to discuss the timeliness of our section 7 consultation process. For 
example, from the date that formal consultation is initiated, the 
Service is allowed 90 days to consult with the agency and applicant (if 
any) and 45 days to prepare and submit a biological opinion. Biological 
opinions may include reasonable and prudent measures and terms and 
conditions, both intended to minimize the impact of incidental take.
    (89) Comment: A State asked whether State natural resource agencies 
be expected to restore the species to State-owned lands where they are 
considered to be extirpated.
    Our Response: The Service will work with the State agencies and 
other stakeholders through recovery planning to identify areas that 
would aid in recovery of these species, and determine appropriate 
actions to take on those lands.
    (90) Comment: A state commented that incentive-based voluntary 
programs work well for other species and may be a better solution to 
conserving the species than listing and critical habitat designations. 
The State would like to provide potential voluntary methods and 
programs to assist and incentivize landowners to implement conservation 
measures and practices that enhance butterfly habitat.
    Our Response: We appreciate any assistance to incentivize 
landowners to conserve these species. Voluntary actions can have a 
significant contribution to conservation. If such measures are in place 
when we are evaluating a species for listing, we consider those 
measures and how they affect the status of the species in our 
determination. The Service's policy regarding voluntary prelisting 
conservation actions (79 FR 42525, July 22, 2014), encourages voluntary 
conservation actions for non-listed species. However, a species may 
still warrant listing if such voluntary actions are not in place when 
we are evaluating a species for listing, or if those actions are not 
sufficient to affect the need to list a species. We suggest you contact 
the Service's Ecological Services Field Office in your State to discuss 
voluntary conservation programs in detail.
    (91) Comment: A State suggested that the Service should develop 
habitat management guidelines and best management practices (HMGs/BMPs) 
in close collaboration with State agencies and others knowledgeable 
about

[[Page 63705]]

effective prairie management. Many State-owned prairies are managed 
with the support of Federal funding, and HMGs/BMPs are needed 
immediately in order for the State agencies to comply with the Act. 
Such HMGs/BMPs should include clear guidance on: Prescribed fire; 
grazing; appropriate use of herbicides on occupied sites; pesticide 
buffers around occupied sites and notice to landowners adjacent to 
occupied sites; adherence to and enforcement of pesticide labels; 
available tools and incentives, including incentives and management 
practices for expanding prairie restoration to adjacent restorable 
lands; distinct measures for occupied habitat and unoccupied habitat, 
including lands targeted for restoration or enhancement; measures for 
restored habitat, and the point at which habitat is considered 
restored; and importance of effectiveness monitoring and adaptive 
management practices in ensuring that HMGs/BMPs produce the desired 
benefits to the species and their habitat.
    Our Response: We appreciate this comment and look forward to 
working with our State partners in implementing conservation and 
providing assistance. The Service has developed conservation guidelines 
for the Dakota skipper that are available online (http://www.fws.gov/midwest/endangered/insects/dask/DASKconservationguidelines.html) and is 
developing similar guidelines for the Poweshiek skipperling. The Dakota 
skipper conservation guidelines address: Prescribed fire management, 
grazing, haying and native seed harvest, habitat preservation, habitat 
restoration, weed/invasive species control, maintenance of genetic 
diversity within populations, and coordinated management. The Service 
looks forward to continued collaboration with State agencies and other 
stakeholders to further develop and refine these conservation 
guidelines. These guidelines will be used as a basis to begin a 
discussion of HMGs/BMPs development.
    (92) Comment: A State suggested that, if HMGs/BMPs cannot be 
completed before the effective date of the listing, the final rule 
should be delayed until the necessary guidance is available.
    Our Response: Section 4(b)(6)(A) of the Act establishes that the 
Service must make a final determination as to its proposed action 
within 1 year of publishing the proposal, unless there is substantial 
disagreement about the sufficiency or accuracy of the available data on 
which that decision is based, for which the Service may seek up to a 6-
month extension.
4(d) Rule
    (93) Comment: A state suggested that the 4(d) rule be expanded to 
exempt take caused by prescribed burns, as it is a valuable habitat 
management tool.
    Our Response: Although we can establish general guidelines for 
managers and landowners who are planning prescribed burns in Dakota 
skipper habitats, we determined that it would not be advisable to 
broadly exempt take caused by burning in the 4(d) rule. The impacts of 
prescribed fires on Dakota skipper populations depend on numerous 
factors that warrant site-specific evaluation, including the number, 
proximity, and size of populations in nearby unburned areas; fuel 
loads; timing of the fire; likelihood of escape from fire units; and 
post-fire management of unburned units. If fires are proposed in areas 
where they are likely to result in take of Dakota skippers, individual 
reviews should be conducted to determine potential effects to the 
species.
    (94) Comment: A state suggested that the 4(d) rule should 
specifically exempt mowing and haying of road rights-of-way under all 
jurisdictions (State, county, or township). Exemptions should apply in 
the area from the road surface to the right-of-way boundary.
    Our Response: We modified the 4(d) rule to exempt take of Dakota 
skippers caused by mowing native grassland for hay after July 15 within 
transportation rights-of-way. Except for mowing of section line rights-
of-way and recreational trails, the 4(d) rule only exempts take of 
Dakota skippers that occurs as a result of mowing or haying that is 
part of routine livestock ranching activities. Except for the two 
specific cases mentioned above--mowing section line rights-of-way and 
recreational trails--the 4(d) rule does not exempt take of Dakota 
skippers caused by mowing that does not produce hay for livestock 
consumption. Regardless, the 4(d) rule exempts take of Dakota skippers 
only if the haying is carried out after July 15. We also further 
clarified that Dakota skippers do not inhabit tame hayland or grassland 
(hayland or grassland planted to, and composed primarily of, nonnative 
grass species, such as smooth brome).
    (95) Comment: One commenting agency indicated its support for the 
4(d) rule, but also stated that it does not support the exemption of 
the listed activities for purposes other than ranching and trail 
maintenance, and requested that the Service clarify that the listed 
activities would not be permitted if used for other categories of 
actions. These activities include haying and spot application of 
herbicides to control noxious weeds.
    Our Response: In the final 4(d) rule, the Service clarifies that 
take would be exempted for certain activities listed in the 4(d) rule 
when carried out in relation to routine livestock operations. We did, 
however, also clarify that take that occurred as a result of mowing 
native grassland for hay would be exempted if conducted after July 15 
in transportation rights-of-way.
    (96) Comment: A State commented that, in the 4(d) rule, only 
exempting spot spraying of weeds is overly restrictive. Leafy spurge, 
for example, cannot be effectively controlled at the seedling stage by 
spot spraying.
    Our Response: We understand that there may be cases where spot-
spraying is insufficient to control outbreaks of noxious weeds. 
Frequent herbicide applications, however, have been associated with 
reduced diversity of native flowering plants in native rangelands 
(e.g., Smart et al. 2011, p. 184). Therefore, take caused by broadcast 
herbicide applications is not exempted by the 4(d) rule. It many cases, 
Dakota skippers may not be present in areas where broadcast 
applications are necessary. The Service can provide technical 
assistance to help determine whether Dakota skipper may be present. If 
noxious weed control is needed where the Dakota skipper is likely to be 
present, the Service will work with landowners or land managers to 
identify techniques that avoid take.
    (97) Comment: One commenter requested guidance on whether 
prescribed fire and the activities described under the 4(d) rule could 
be implemented ``on sites that might have historically supported'' 
Dakota skipper.
    Our Response: Take of Dakota skipper is prohibited under the Act, 
unless it is a specific action that is exempted under the 4(d) rule, 
which applies to all State, private, or tribal lands. If an action is 
implemented on a site where the Dakota skipper is no longer present, 
then take is unlikely. An action could result in take of Dakota 
skippers at sites where the species has been extirpated if key habitat 
features are still present and an extant population inhabits a nearby 
area. In those cases, Dakota skipper may have reoccupied the site, and 
we recommend coordinating with the Service to ensure that a proposed 
activity is not likely to result in take of Dakota skippers.
    (98) Comment: One commenter stated that the list of counties in 
which the proposed 4(d) rule did not exempt take caused by grazing 
(Eddy, McHenry, Richland, Rolette, Sargent, and Stutsman) did not 
directly correspond

[[Page 63706]]

to the list of counties in which critical habitat was proposed 
(McHenry, McKenzie, Ransom, Richland, Rolette, and Wells).
    Our Response: We revised the 4(d) rule to exempt take caused by 
grazing throughout the range of the species, and not limited to certain 
counties. Thus, the final 4(d) rule exempts take of Dakota skippers 
caused by livestock grazing on all private, State, tribal, and other 
non-Federal (e.g., county) lands.

Public Comments

General
    (99) Comment: A number of public comments opposed the listing of 
the Dakota skipper and Poweshiek skipperling as federally threatened or 
endangered species, but provided no substantive scientific or 
commercial evidence suggesting that listing is not warranted.
    Our Response: While we appreciate the opinion of all interested 
parties, the Service must base its decision of whether to list the 
Dakota skipper and Poweshiek skipperling solely on the basis of the 
best scientific and commercial data available.
    (100) Comment: Several comments stated that listing these species 
will interfere with private property rights and cause economic impacts, 
such as reduction in land values, fines to citizens, prohibitions to 
development, wasteful use of taxpayer money, and intrusion to grazing 
and farming operations.
    Our Response: For listing actions, the Act requires that we make 
determinations ``solely on the basis of the best available scientific 
and commercial data available'' (16 U.S.C. 1533(b)(1)(A)) regarding the 
status of the species. Therefore, we do not consider any information 
concerning potential economic or other possible impacts when making 
listing determinations. We will work with entities to conserve the 
butterflies and develop workable solutions. Furthermore, in this rule, 
we have included a 4(d) rule for the Dakota skipper that exempts take 
from certain routine grazing activities. The presence of a listed 
species does not give government employees or representatives any 
rights to access private property.
    (101) Comment: A commenter stated that the Service did not use the 
best available science in the proposal. There is a lack of evidence to 
justify the proposed actions.
    Our Response: The comment did not provide details on what 
scientific information we failed to consider in our proposal. In 
preparation of the proposal and this final rule, we used the best 
available scientific and commercial information of which we are aware. 
We sought comments from independent peer reviewers to ensure that our 
determination is based on scientifically sound data, assumptions, and 
analysis. The peer reviewers stated that our proposed rule was based on 
the best available scientific information. Additionally, the results of 
2013 surveys conducted throughout the range of both species in the 
United States and information from recently published research 
conducted in Saskatchewan and Manitoba were considered in our final 
listing rule.
    (102) Comment: A commenter stated that listing under the Act and 
critical habitat designations are intertwined and cannot be separated, 
as the Service has done with these proposals.
    Our Response: When a species is proposed for listing as endangered 
or threatened under the Endangered Species Act (Act), we must consider 
whether there are areas of habitat we believe are essential to the 
species' conservation. The listing determination and critical habitat 
determination for the Dakota skipper and Poweshiek skipperling were 
conducted at the same time and in coordination with each other. The 
proposed rules for each action were published on the same date, but in 
separate documents. We are currently working to finalize the critical 
habitat determination for these two species, which will be published 
shortly.
    (103) Comment: A commenter requested that we clarify the status 
that is proposed for each species, as it is confusing which is proposed 
as threatened and which as endangered.
    Our Response: The Dakota skipper is listed in this rule as a 
threatened species, and the Poweshiek skipperling, as an endangered 
species.
    (104) Comment: A commenter requested that the listing and critical 
habitat designations for these species will create an adversarial 
atmosphere between the Service and the agricultural community, and 
punish producers, who are the best stewards of habitat for a variety of 
species.
    Our Response: We based our listing decisions on the basis of 
biological information and have determined that the Dakota skipper is 
threatened and the Poweshiek skipperling is endangered under the Act. 
The Service is committed to working with private landowners, public 
land managers, conservation agencies, nongovernmental organizations, 
and the scientific community to conserve the Dakota skipper and 
Poweshiek skipperling and their habitats. For example, in recognition 
of efforts that provide for conservation and management of the Dakota 
skipper and its habitat in a manner consistent with the purposes of the 
Act, we developed a 4(d) rule that outlines the prohibitions, and 
exceptions to those prohibitions, necessary and advisable for the 
conservation of the Dakota skipper. We believe that exempting 
incidental take of Dakota skippers that may result from grazing in 
certain geographic areas will afford us more time to protect the 
species' habitats in these areas and will facilitate the coordination 
and partnerships needed to recover the species.
    (105) Comment: The North Dakota Stockman's Association commented 
that they have policy supporting the use of sound science in 
decisionmaking. Much of the science used to develop these proposals was 
not peer-reviewed or published, and was largely based on internal 
documents. The Service's own ``Information Standards Under the 
Endangered Species Act'' policy calls for ``review of all scientific 
and other information used by the Services to prepare biological 
opinions, incidental take statements, and biological assessments to 
ensure that any information used by the Services to implement the Act 
is reliable, credible, and represents the best scientific and 
commercial data available.'' Sound, peer-reviewed science needs to be 
the foundation of any proposal, but particularly of those with such 
serious implications for citizens.
    Our Response: Under the Act, we are obligated to use the best 
available scientific and commercial information, which in this cased 
included results from surveys, reports by scientists and biological 
consultants, natural heritage data, and expert opinion from biologists 
with extensive experience studying the Dakota skipper and Poweshiek 
skipperling and their habitats, whether published or unpublished. The 
Service's databases were also referenced several times within the 
document (e.g., Service 2014, unpublished geodatabase). These databases 
were built using hundreds of sources, including unpublished reports, 
published papers, and State heritage data. We referenced these 
databases in the proposed and final listing document, in places where 
we summarized data across many sources. All of the reports utilized in 
these databases are publically available, upon request.
    Additionally, we sought comments from independent peer reviewers to 
ensure that our determinations are based on scientifically sound data,

[[Page 63707]]

assumptions, and analysis. We solicited information from the general 
public, nongovernmental conservation organizations, State and Federal 
agencies that are familiar with the species and their habitats, 
academic institutions, and groups and individuals that might have 
information that would contribute to an update of our knowledge of the 
species, as well as the activities and natural processes that might be 
contributing to the decline of either species. The existing body of 
literature on the Dakota skipper and Poweshiek skipperling, including 
results from surveys, reports by scientists and biological consultants, 
natural heritage data, and expert opinion from biologists with 
extensive experience studying the Dakota skipper and Poweshiek 
skipperling and their habitats, whether published or unpublished, is 
the best available information.
    (106) Comment: A commenter noted that the Dakota skipper listing 
priority number indicating threats of moderate to low magnitude.
    Our Response: The Service believes that the Dakota skipper warrants 
protection under the Act, as a threatened species, as discussed in 
detail in this final listing rule. The listing priority number was 
changed from 11 to 8 on December 6, 2007 (72 FR 69034), and the Dakota 
skipper remained a candidate species with a listing priority number of 
8 in subsequent notices through October 26, 2011 (76 FR 66370). The 
listing priority numbers range from 1 to 12, indicating the relative 
urgency for listing plants or animals as threatened or endangered. The 
criteria used to assign this number reflect the magnitude and immediacy 
of threat to the species, as well as the relative distinctiveness or 
isolation of the genetic material they possess. This latter criterion 
is applied by giving a higher priority number to species that are the 
only remaining species in their genus, and a lower priority number to 
subspecies and varieties. The listing priority number assigned to a 
species, however, does not necessarily reflect the classification the 
Service ultimately determines is appropriate for a species when making 
a listing determination, as new information may become available that 
affects that decision.
    (107) Comment: A commenter questioned how this listing would 
adversely affect other species.
    Our Response: We are unaware of any adverse effects that these 
listings would have on other native species of plants or animals. 
Nonnative or invasive plant species and species of woody plants 
encroaching into prairie habitats may be managed to maintain or 
increase the quality of native-prairie habitats.
    (108) Comment: Commenters asked whether those who are enrolled in 
the Conservation Reserve Program, Environmental Quality Incentive 
Program, or other U.S. Department of Agriculture programs would be 
subject to special requirements. How will the listing affect those who 
have Federal crop insurance, have received a Federal loan or Federal 
disaster assistance, or own property that has a Federal easement? If a 
landowner is required to seek consultation before requesting Federal 
funding or authorization for an action that may affect a listed species 
or critical habitat, what cost will be involved, both in terms of money 
and time? Will this be reflected in the economic impact analysis the 
Service is preparing?
    Our Response: Proposed projects in areas where one or both species 
may be present or on designated critical habitat that has a Federal 
nexus (in other words, funded, authorized, or carried out by a Federal 
agency) will be required to undergo consultation with the Service under 
section 7 of the Act. In such cases, it is the responsibility of the 
Federal agency involved to complete the consultation. In those 
instances, the action agency should contact the Service's Ecological 
Services Office in their State if they are planning an activity that 
may affect the species or its critical habitat. For more information 
about section 7 consultations, visit the Service's Web site (http://www.fws.gov/endangered/what-we-do/consultations-overview.html). In 
accordance with the Act, we cannot consider possible economic impacts 
in making a listing determination. However, section 4(b)(2) of the Act 
states that the Secretary shall designate and make revisions to 
critical habitat on the basis of the best available scientific data 
after taking into consideration the economic impact, national security 
impact, and any other relevant impact of specifying any particular area 
as critical habitat.
    (109) Comment: One commenter recommended that better documentation 
is needed when Landowner Incentive Program grants or other government 
funding is used.
    Our Response: Government-funded grant accomplishment reports are 
typically available online. Information on our grant programs available 
to aid species recovery can be found at http://www.fws.gov/grants.
    (110) Comment: Private landowners who are participating in the 
Service's recovery program for the Karner blue butterfly commented that 
private landowners are critical to the protection of endangered and 
threatened species. Private landowners often provide suitable `stepping 
stone' habitat otherwise unavailable to public agencies. The Federal 
status of the Karner blue butterfly facilitated habitat improvements 
and public awareness that may not have occurred but for the protection 
of that species. The commenter believes that listing the Dakota skipper 
and Poweshiek skipperling will similarly benefit these two species.
    Our Response: We thank you for your comment and participation in 
species recovery efforts. The Service understands the importance of 
private landowner participation and support in recovery of the Dakota 
skipper and Poweshiek skipperling and will continue to work with all 
stakeholders to this end.
    (111) Comment: One commenter expressed disappointment with the 
Service stating that other Service projects that are of great benefit 
to society, the commenter did not believe that listing the butterflies 
was one of them. The commenter questioned why these two butterflies are 
of such importance that they should be listed.
    Our Response: In the preamble to the Endangered Species Act of 
1973, Congress recognized that endangered and threatened species of 
wildlife and plants ``are of esthetic, ecological, educational, 
historical, recreational, and scientific value to the Nation and its 
people.'' In this statement, Congress summarized convincing arguments 
made by scientists, conservationists, and others who are concerned by 
the disappearance of unique creatures. The Service is responsible for 
implementing the Act, and as such, must determine whether any species 
is an endangered or threatened species, based on the best scientific 
and commercial data available regarding the status of that species, not 
based on a certain benefit to society or importance.
    Although the Service does not consider the value of a particular 
species when making a listing determination, these butterflies are 
important and do provide a societal benefit. Humans depend on the 
variety of life for food, clothing and medicines. When we lose species 
we lose their potential for the future and we lose their effect on 
other species which, in turn, have ecosystem roles and future value. 
Continued degradation of our lands and waters that reduces our 
biological diversity--the variety of life--is important. Habitat and 
water degradation, and maybe even climate change, can be reversed, but 
the loss of a species and its genes are irreversible.

[[Page 63708]]

Further, the prairie ecosystem is not completely gone, yet, but it will 
be if we do not take measures to save its plants and animals. 
Protecting these small butterflies means protecting their habitats, so 
that some of this ecosystem, with all its variety of life, remains. 
Humans depend on the variety of life for food, clothing and medicines. 
The variety of life that we have in this country, including functioning 
ecosystems, is our natural heritage.
    (112) Comment: One commenter stated that change, both desired and 
undesired, is a natural part of the evolutionary cycle.
    Our Response: Although extinctions occur naturally, scientific 
evidence strongly indicates that the current rate of extinction is much 
higher than the natural or background rate of the past. The main force 
driving this higher rate of loss is habitat loss. Over-exploitation of 
wildlife for commercial purposes, the introduction of harmful exotic 
(nonnative) organisms, environmental pollution, and the spread of 
diseases also pose serious threats to our world's biological heritage. 
None of these creatures exists in a vacuum. All living things are part 
of a complex, often delicately balanced, network called the biosphere. 
The earth's biosphere, in turn, is composed of countless ecosystems, 
which include plants and animals and their physical environments. No 
one knows the myriad ways the extinction of organisms will affect the 
other members of its ecosystem, but the removal of a single species can 
set off a chain reaction affecting many others. Furthermore, many 
individual species are uniquely important as indicators of 
environmental quality. The rapid decline of the Poweshiek skipperling 
and Dakota skipper may be an indicator of a greater environmental 
problem. Regardless of the reason for the species' decline, it it meets 
the definitions of a threatened or endangered species under the Act, we 
are obligated list it under the Act.
    (113) Comment: A commenter noted that prairie ecosystems are one of 
the most endangered ecosystems of the world. Currently only 4 percent 
of remnant tallgrass prairie remains in the United States, and the loss 
in habitat has led to the declines in the Poweshiek skipperling and 
Dakota skipper. Furthermore, these two species play an important role 
in the prairie ecosystem, and by protecting them, we also protect other 
prairie plants and animals.
    Our Response: Native tallgrass and mixed-grass prairies have been 
reduced by 85 to 99.9 percent of their former area throughout the 
historical range of both species (Samson and Knopf 1994, pp. 418-419). 
Even further destruction of remnant prairies has occurred since Samson 
and Knopf's study. Conversion is discussed in Factor A of this final 
listing rule, below.
    (114) Comment: A commenter stated that the limits and prohibitions 
on land uses like grazing and haying that are a result of this listing 
will negatively affect livestock producers. For example, the areas in 
North Dakota within the range of the butterflies are significant beef-
producing counties. Limiting grazing or haying on those lands will have 
serious economic ramifications for the cattle-ranching landowners. 
Because of the terrain, some of these lands are suited only for 
livestock grazing. If those lands cannot be used for that purpose, 
their value will largely be diminished. Under the Service proposals, 
six North Dakota counties are deemed too sensitive for grazing, and it 
appears that grazing will be prohibited there altogether.
    Landowner concerns about compliance could influence those impacted 
to convert their grass and haylands to other uses before a final rule 
is in effect. This would be detrimental to both the livestock industry 
and the butterflies the Service is aiming to protect.
    Our Response: Through public meetings, meetings with private 
landowners, and outreach efforts, the Service has attempted to reduce 
the concerns of private individuals. It is important for private 
individuals to know that only those projects or actions that occur in 
areas where the butterflies may be present or on designated critical 
habitat and that have a Federal nexus (in other words, funded, 
authorized, or carried out by a Federal agency) must undergo 
consultation with the Service under section 7 of the Act. In such 
cases, it is the responsibility of the Federal agency involved to 
complete the consultation. We suggest that private landowners contact 
their local Service Ecological Services Office if they are planning an 
activity with a Federal nexus that may affect the species or its 
critical habitat. For more information about section 7 consultations, 
visit the Service's Web site (http://www.fws.gov/endangered/what-we-do/consultations-overview.html). Under the 4(d) rule for the Dakota 
skipper, take of Dakota skippers caused by certain routine livestock 
operations on all non-Federal lands is exempt from the prohibitions 
under section 9 of the Act. For more information on the 4(d) rule for 
the Dakota skipper, refer to the Provisions of the 4(d) Rule for the 
Dakota Skipper section of the preamble to this final rule.
    (115) Comment: A commenter stated that livestock owners are the 
original stewards of this land and other natural resources, and the 
general management practices utilized by these owners are ecologically 
sound and enhance the productive capabilities of the land. These 
practices may even be enhancing the habitat for these two butterflies. 
As private landowners and stewards of livestock, land, and other 
natural resources, we look for policies that allow coexistence and do 
not threaten our livelihood.
    Our Response: We appreciate your comment. Landowners deserve great 
credit for their land stewardship, and we want to continue to encourage 
those management practices that support the butterflies. The Service 
also strives to find ways to work with people while protecting 
imperiled species. To this end, the Act allows for some flexibility for 
species that are listed as threatened; the Service is able to tailor 
the protections of the Act to what it deems as necessary and advisable 
to provide for the conservation of such species. We have developed a 
4(d) rule for the Dakota skipper that provides for the conservation of 
the species while allowing some flexibilities for landowners. This 4(d) 
rule exempts incidental take of Dakota skippers that is caused by 
certain routine livestock operations and mowing of recreational trails. 
For more information on the 4(d) rule for the Dakota skipper, refer to 
the Provisions of the 4(d) Rule for the Dakota Skipper section of this 
final rule, below.
Biology and Habitat
    (116) Comment: A commenter stated that the Service is correct to 
rely on Royer et al. (2008) for understanding and describing Dakota 
skipper habitat. Dakota skipper data in Minnesota are overwhelmingly 
attributable to Type B (upland prairie: Dry-mesic or dry). However, 
type A and B habitats can blend into each other. As correctly described 
by the Service here, upland and lowland prairie are often intermixed in 
both habitat types (A and B).
    Our Response: We describe prairie types as Type A or Type B 
habitat, but realize that the two habitat types may be intermixed, 
there may be smaller patches that may be better categorized, or 
specific microhabitats that the species uses at various times to 
fulfill their biological needs.
Occupancy
    (117) Comment: A commenter stated that the definition of occupancy 
is

[[Page 63709]]

difficult to understand and should be clarified.
    Our Response: We clarified the definition of occupancy in this 
final rule by adding language that clarifies that the three sequential 
years of negative surveys necessary to consider the species extirpated 
from a site could be from any survey year. We also clarified that the 
occupancy status of an extirpated site would not change unless the 
species was detected at that location during future surveys. We strove 
to be as accurate as possible in defining occupancy for the purposes of 
the listing and critical habitat determinations. If you are unsure 
whether either species may occur on your property, we suggest you 
contact the Service's Ecological Services Field Office in your state.
    (118) Comment: A commenter stated that the Service's methodology 
for classifying occupancy is well supported. Given the difficulties of 
detecting these small butterflies most observable in the brief period 
per year when it is in the adult life stage, a conservative approach is 
justified. The timing of the adult flight period and the species' 
abundance varies greatly among years, due to climatic variation. At 
least 3 years of surveys are needed before an area should be considered 
extirpated. Furthermore, those 3 years of surveys need to be detailed 
efforts per survey, with multiple dates of surveys per year.
    Our Response: We appreciate your comment in support of our 
occupancy rationale. We agree that multiple dates of surveys per year 
are desired to verify non-detection of the species in a given year. We 
have added language to clarify that point in the Background section of 
this final listing rule, above.
    (119) Comment: A commenter stated that the determinations to list 
these two butterflies are based on historical declines, although 
significant documentation of butterfly fauna did not occur until 1960, 
and it is, therefore, impossible to determine anything about the 
historical range or any possible historical declines. How are past 
declines relevant to the species now, and why is the Service listing 
these species now, as opposed to when those declines were occurring? It 
is not possible to characterize the magnitude of threats to these 
species without knowing what has caused the historical decline and 
understanding what constitutes natural levels of inter-annual 
population fluctuation.
    Our Response: We consider historical declines, and the ongoing 
effects of those historical declines, as well as current and recent 
declines, in our determinations. Significant population declines have 
occurred in both species very recently and are still ongoing, and the 
effects of historical declines continue to impact both species today. 
Populations that were historically fragmented by habitat destruction 
continue to be isolated from one another, which may have negative 
genetic consequences or increased vulnerability to stochastic events, 
for example.
Population Status and Distribution
    (120) Comment: A commenter stated that the survey methods are 
inadequate and poorly described. In particular, it appears that a high 
percentage of survey sites are in close proximity to roads. These sites 
may be disturbed sites, and some literature indicates Dakota skippers 
do not occupy formerly disturbed and subsequently restored sites.
    Our Response: As described in the Background section of this final 
listing rule, above, Dakota skippers occupy native-prairie sites that 
have never been plowed. During the adult flight period, it is possible 
that Dakota skipper may use lesser quality grassland dominated areas to 
travel (disperse) from one native-prairie site to another nearby 
native-prairie site. Surveys were conducted using various protocols 
(for example, Pollard walks (Pollard 1975), modified Pollard walks, 
wandering transects, and timed transects) depending on the objective of 
the survey, funding, or available resources and staff. Describing the 
details of survey methods for each site is beyond the scope of this 
rule, however, those details are described in the survey reports that 
are cited within this final rule. We added some brief examples of 
commonly used survey methodologies in the Background section of this 
final listing rule.
    (121) Comment: A few commenters suggested that there are multiple 
approaches to interpreting data and conducting trend analyses. One such 
suggested approach is to use the concepts of Schlicht et al. (2009, 
Table 10, p. 439) and Swengel and Swengel (2012b, Table 2). The 
observed timing of population declines may differ depending on the 
approach used. As such, the commenter cautions that the information 
included in Figures 1 and 2 of the proposed listing rule should be 
interpreted carefully, and provides specific suggestions for an 
alternate approach.
    Our Response: We acknowledge that there are other ways to look at 
the data and the approach suggested by the commenter would be a good 
way to determine the apparent disappearance (either absence or 
undetectable levels) of a species at each particular site. These types 
of analyses may be an appropriate approach for recovery planning and 
implementation, and we will consider their utility at that time. We 
believe the way we interpreted the data in the listing rule is 
appropriate for looking at the overall trends in detections and non-
detections of the species through the years across all of the known 
sites, without relying on the numbers of individuals observed at each 
site during each survey year, since we often do not have those data. 
Although many of the skipper sites have been surveyed over multiple 
years, the frequency and type of surveys varied among, and sometimes 
within, sites and years. Surveys may have been conducted using various 
protocols and with varied objectives and, therefore, had varying 
results. For instance, some surveys focused simply on documenting 
species presence while others documented the numbers observed in a 
certain area, distance, or period of time. Whether or not the species 
was detected in a given year is the only common result of all the 
surveys, so that is the data we used to evaluate trends through time.
    (122) Comment: One private citizen commented that he has never 
observed the Dakota skipper and the Poweshiek skipperling on his 
property or anywhere else.
    Our Response: Dakota skippers and Poweshiek skipperlings have a 
single adult flight period per year that typically occurs from the 
middle of June through the end of July. The actual flight period varies 
somewhat across the range of each species and can also vary 
significantly from year-to-year, but typically lasts 2 to 4 weeks. Both 
the Dakota skipper and Poweshiek skipperling are small and cryptic 
species. Therefore, it is unlikely someone will observe these two 
species unless they are actively searching for the species in suitable 
habitat within their ranges during the short adult flight period. The 
likelihood of observing these species recently is low, because these 
two species have reached undetectable levels, even by experienced 
observers, at most of their known locations.
    (123) Comment: One commenter recommended that surveying and 
monitoring protocols be developed for the two species.
    Our Response: Because the objectives of surveys may vary across the 
range of these species, we recommend contacting the Service's 
Ecological Services Field Office in your State to discuss the 
appropriate survey protocol to use for

[[Page 63710]]

particular projects, habitat types, and geographic areas. To facilitate 
effective cooperation among agencies, organizations, and individuals 
interested in the distribution of these species, the Service will 
maintain a list of individuals who meet certain qualifications for 
conducting reliable surveys for the target species.
    (124) Comment: One commenter provided results from butterfly 
surveys conducted for the past 19 years (1995-2013) in Clay and Polk 
counties, Minnesota. Low numbers of Dakota skippers were observed in 
1996, 2006, 2007, and 2010. The Poweshiek skipperling was observed in 
1997-2002, 2004-2006, and two individual Poweshiek skipperlings were 
observed in 2013.
    Our Response: We appreciate receiving the new information on Dakota 
skipper and Poweshiek skipperling occurrences in Minnesota. We verified 
the information with Minnesota Department of Natural Resources staff (a 
qualified surveyor), who confirmed the validity of the data. We 
confirmed that the individual was capable of identifying the Poweshiek 
skipperling and that the 2013 observations were valid. This information 
was incorporated into this final listing rule. The Service has 
prioritized the Polk County location for surveys in future years.
    (125) Comment: A commenter noted that the Service included two 
graphs indicating a decline in Dakota skipper sites in Minnesota and 
South Dakota, but did not include a graph for North Dakota. The 2012 
abstract by Royer indicates that ``essentially the same proportion of 
count locations hosted detectable Dakota skipper populations . . .'' in 
1996, 1997 and 2012, but that the encounters per hour had decreased. 
The commenter contend that fewer ``encounters per hour'' could be the 
result of many factors, including the very specific conditions 
necessary to do an accurate sampling. The summary data does not provide 
the necessary background to determine other factors that could have 
influenced the ``encounters per hour'' count.
    Our Response: The detection versus non-detection data for Dakota 
skippers in North Dakota produced no clear trend. If we examine years 
with more than 10 sites surveyed, for example, we find that in 1991, 
the species was detected at 19 of the 31 sites surveyed (61 percent); 
in 1995, the species was detected at 5 of the 10 sites surveyed (50 
percent); in 1996, the species was detected at 13 of the 18 sites 
surveyed (72 percent); in 1997, the species was detected at 10 of the 
25 sites surveyed (40 percent); in 1998, the species was detected at 11 
of the 17 sites surveyed (65 percent); and in 2012, the species was 
detected at 15 of the 27 sites (56 percent) surveyed (where the species 
had previously been observed). Royer (2012) was correct that the 
proportion of sites with detections versus non-detections of Dakota 
skippers were similar (e.g., statewide proportions in 1996 (72 
percent), 1997 (40 percent), and 2012 (56 percent)). Therefore, we 
examined the results of sites that Royer (2012) surveyed using methods 
that quantified results such that they could be compared among years.
    Royer used the same survey protocol, timed transect searches (where 
the number of individuals observed per hour were recorded), for the 
surveys conducted in 1996-1997, 1998, and 2012 (Royer 1997, Royer and 
Royer 2012b). Furthermore, Royer's 1996, 1997, 1998, and 2012 surveys 
(Royer 1997, Royer and Royer 2012b) adhered to our acceptable survey 
standards (e.g., wind speeds, time of day). Therefore, the variation in 
numbers observed attributable to survey error is expected to be 
negligible. Average encounter frequencies observed across the State in 
2012 (10.7 encounters per hour) were lower than during the 1996-1997 
and 1998 statewide surveys (North Dakota State average = 16.94 
encounters per hour and 22.67 encounters per hour, respectively). At 
the site level, sites surveyed in 1996-1997 or 1998 generally had 
higher numbers of Dakota skippers encountered per hour than in 2012.
    (126) Comment: A commenter stated that the proposed listing of the 
Dakota skipper as a threatened species is unwarranted at this time. In 
North Dakota, surveys show that essentially the same proportion of 
locations had detectable levels of Dakota skipper in 1996-1997 (46 
percent) as in 2012 (46 percent). Additionally, new sites have been 
discovered in North Dakota, even though a systematic survey has not 
been conducted. A substantially lower encounter rate in 2012 compared 
to historical surveys was reported, but one year of data does not 
justify listing.
    Our Response: Although the proportion of sites surveyed with 
positive detections of the species is similar when comparing sites 
surveyed in North Dakota in 1996-1997 with those surveyed in 2012, the 
numbers of individuals observed recently were substantially lower than 
in previous surveys; see our response to Comment 125. In addition to 
the survey data and population trend information, the Service also 
considers listing species based on an analysis of threats, described in 
detail in this final listing rule. The results of that threat analysis 
indicates that all of the Dakota skipper sites where the species is 
considered to be present or unknown in North Dakota have one or more 
documented threat of moderate to high levels. At least one moderate- to 
high-level threat is documented in all Minnesota, North Dakota, South 
Dakota, and Canada Dakota skipper sites with present or unknown 
occupancy.
    (127) Comment: A commenter stated that the Service rightly states 
that most Poweshiek skipperling decline likely went unrecorded because 
most prairie destruction occurred prior to 1960, but most prairie 
butterfly surveys post-date those declines. Most decline during 1960-
2000 also went largely undocumented. This is evidenced by the large 
number of sites in Minnesota that fall into an uncertain occupancy 
category. Longer term Poweshiek skipperling decline has been masked by 
data paucity and turnover in sites surveyed.
    Our Response: We agree that there is a paucity of data at many 
sites in recent years (1960-1993). However, most Poweshiek skipperling 
sites and Dakota skipper sites have been surveyed at least once in 1993 
or more recently. The lack of surveys at a given site since 1993 does 
mean that we are uncertain of the occupancy at many sites. We used a 
cautious approach; by assigning sites unknown status, we cannot say 
that the species is truly absent or extirpated from a site, while 
acknowledging that the species may still be present, possibly at 
undetectable levels, if suitable habitat is still present. More surveys 
are needed at these sites to determine if the species is present.
    (128) Comment: A commenter stated that, at the time of Swengel's 
(1992) review, Poweshiek skipperlings had fewer known populations, were 
more highly concentrated in preserves (a single kind of ownership and 
land use category), were in a narrower range, were more concentrated in 
a highly destroyed ecosystem (tallgrass prairie), and had a worse 
immediate response to typical preserve management (fire) than Karner 
blue butterflies, which were federally listed in 1992. Poweshiek 
skipperlings are capable of high local abundance in a few sites, but 
these population numbers are highly volatile, and so extremely low 
numbers also occur during these abundance fluctuations. Compared to 
Dakota skipper incidence within Poweshiek skipperling range, Poweshiek 
skipperlings occurred on relatively more preserves, but Dakota skippers 
had a range further west, including mixed-

[[Page 63711]]

grass prairie, less of which has been destroyed. Also, the Dakota 
skipper is more compatibile with agricultural uses on ranch land (e.g., 
Royer 1992; Marrone 1992). Thus, the Dakota skipper had relatively more 
habitat, even if there were fewer known sites specifically in 
Minnesota. Furthermore, there is a tendency to assume that habitat 
protection (making a site a preserve) means the skippers in the 
preserve are secure; thus, if few are found on a given survey, the 
assumption is that this is due to the surveys being conducted at the 
wrong time, or due to fluctuations in abundance resulting from climatic 
variation. It is only through consistent long-term monitoring with the 
sites held constant (as in Swengel and Swengel 2013) that trend can be 
distinguished from those issues.
    Our Response: Because of the number of historical sites and the 
various ways that data were collected at those sites, we examined the 
range-wide data using detections and non-detections. We agree that 
there are few sites with consecutive years of data, and even fewer that 
have data over the long term. We have examined the data at individual 
sites where we had several consecutive years of data, and found that 
Poweshiek skipperling numbers have appeared to decline, along with the 
number of sites with positive detections (vs. non-detections) of the 
species.
    (129) Comment: A commenter stated that the sudden recent decline in 
Poweshiek skipperlings over the last 10 years is likely because there 
are few new populations being discovered to replace the already 
undetectable, previously known populations. Furthermore, 
conservationists identified the best sites first; thus, more recently 
discovered populations were not as large and robust as the earlier 
discovered populations. Those more fragile populations would have less 
favorable prospects for long-term persistence. This also contributes to 
the sense that decline is now occurring everywhere. In addition, in 
some places, such as North Dakota, the dramatic population declines of 
the Poweshiek skipperling primarily occurred prior to 2000 (see Royer 
and Marrone 1992a, b; and Orwig 1994; 1995; 1996; and 1997).
    Our Response: We acknowledge that there are documented declines in 
Poweshiek skipperling populations prior to 2000. However, in our 
comprehensive review, it appears that many sites with known populations 
of Poweshiek skipperlings have simultaneously declined to undetectable 
levels across much of the species' range in the early 2000s.
Factors Affecting the Species--General
    (130) Comment: A commenter stated that, throughout the proposed 
listing rule, the Service attributes perceived threats to the Dakota 
skipper as threats to the Poweshiek skipperling or vice versa. The 
Service must independently evaluate threats to each species and may not 
assume that a threat to one species is necessarily a threat to the 
other.
    Our Response: We have conducted the analysis of factors affecting 
the species separately for the two species. Since these two species 
have similar biology and are often found in the same locations, they 
face similar or identical threats at many locations. Therefore, when 
describing the factors, we discuss their effects to both species 
together when they are the same or similar. For example, if a remnant 
(untilled) native tallgrass prairie is being considered for a housing 
development, the resulting habitat conversion would affect both species 
by removing suitable habitat from the landscape.
    (131) Comment: A commenter stated that listing these species will 
impede the use of certain grassland management tools such as grazing, 
haying, burning, and chemical spraying that are necessary to meet the 
desired habitat for these butterflies.
    Our Response: The listing of these two butterflies will not 
necessarily impede the use of these grassland management tools. The 
Service recognizes that management, including grazing, haying, 
prescriptive fire or targeted herbicide treatments, may be needed to 
benefit the species and their habitats, as discussed in Factor A and 
Factor E of this final listing rule, below. The types, extent, 
duration, and intensity of various management regimes that would 
benefit the butterflies may depend on the specific past, present, or 
future threats at that location. The success of management regimes will 
need to be monitored and adjusted accordingly.
    (132) Comment: A commenter noted that suggestions of ``light,'' 
``limited'' and ``no'' grazing and ``late-season haying'' are mentioned 
in the proposed rule to support rebuilding the butterfly populations. 
However, such practices have proven to have long-term implications that 
will actually do the opposite. For instance, limiting or eliminating 
grazing and haying is likely to promote invasion by exotic grasses, 
such as smooth brome grass and Kentucky bluegrass, which will compete 
with the very same native species that the butterflies require for 
habitat. The Service should encourage and incentivize grazing and 
haying approaches, such as rotational grazing, that would support both 
the economic viability of livestock operations and butterfly population 
growth.
    Our Response: Conservation of Dakota skipper and Poweshiek 
skipperling populations relies on careful implementation of management 
practices that conserve its habitat while minimizing adverse effects to 
reproduction and survival. Rotational late-season haying after the 
adult flight period, for example, can be beneficial to the species' 
habitat. We have developed Dakota skipper conservation guidelines 
(http://www.fws.gov/midwest/endangered/insects/dask/DASKconservationguidelines.html), which describe those practices in 
more detail, and are developing similar guidelines for the Poweshiek 
skipperling. We discuss both the harm and the benefits that various 
management practices may have on prairie habitats in Factors A and E of 
this final listing rule (below).
    (133) Comment: A commenter stated that grassland easements are a 
broad-brush approach to conserve native prairies, but there is no 
targeted program or recovery plan specific to the Dakota skipper that 
would provide financial incentives and technical information for 
ranchers and farmers to manage habitat in a way that would expand the 
population of Dakota skippers.
    Our Response: Service programs, including Partners for Fish and 
Wildlife and State and tribal grant programs, are available to develop 
projects and partnerships to conserve these and other species. 
Following listing, the Service will develop a recovery plan for these 
two species.
    (134) Comment: A commenter stated that beaver dams can cause water 
level fluctuations in some Poweshiek skipperling areas in Michigan. The 
commenter asked whether these fluctuations, or the act of returning the 
water level to its normal level, harm Poweshiek skipperling larvae or 
habitat.
    Our Response: It is possible that higher than normal water levels, 
for an extended amount of time, may harm larvae. We discuss fluctuating 
water levels in Factor E of this final listing rule, below.
Factor A
    (135) Comment: A commenter stated that current Dakota skipper 
population sites are already protected, and the imminent threat to the 
species is deemed to be on ``remnant habitat.''
    Our Response: While some Dakota skipper sites are on land that is 
protected from some threats, such as

[[Page 63712]]

conversion of remnant prairies to other uses, the Dakota skipper 
populations at these sites are still exposed to other stressors, as we 
detailed in the Summary of the Factors Affecting the Species section of 
this final listing rule, below.
    (136) Comment: A commenter stated that the Dakota skipper and 
Poweshiek skipperling do not warrant listing because the Service 
improperly characterized oil and gas development as a threat to the 
Dakota skipper and Poweshiek skipperling, overstated the amount of oil 
and gas development occurring in the ranges of the Dakota skipper and 
Poweshiek skipperling, incorrectly assumed that the level of oil and 
gas development seen in western North Dakota will occur throughout the 
species' ranges, and erred by concluding that impacts from oil 
development in western North Dakota to the two butterflies are similar 
to impacts from coal-bed natural gas in Wyoming on the greater sage-
grouse. Accordingly, the Service should withdraw the listing and 
critical habitat rules.
    Our Response: The Act directs us to determine whether a species is 
an endangered species or a threatened species because of any factors 
affecting its continued existence. Listing actions may be warranted 
based on any of the five factors, singly or in combination. We 
completed a comprehensive assessment of the biological status of the 
Dakota skipper and Poweshiek skipperling, and all factors that might 
affect its existence. The effects from oil and gas activities are just 
one of the factors we considered. Our determinations that the Dakota 
skipper is a threatened species and the Poweshiek skipperling is an 
endangered species are based on numerous threats, acting individually 
and synergistically, that are leading to substantial population 
declines.
    Specifically with regard to our evaluation of impacts from oil and 
gas activities, much of this activity is currently occurring in areas 
of native prairie overlying the Bakken and Three Forks formations, to 
the west of known locations for both butterfly species. However, 
current Bakken oil and gas development is occurring in two counties 
that have records of Dakota skippers (McKenzie and McLean counties in 
North Dakota). In those areas, oil and gas development is a stressor to 
the populations that may be present. Because there are few locations 
where the butterflies may still be extant, significant stressors to 
these few populations can be threats to the species as a whole. 
Furthermore, although oil and gas development is unlikely to occur 
throughout the entire range of the two butterflies in the foreseeable 
future, there may be future development or increases in current 
activities associated with the shale-oil formations (such as the Bakken 
formation in North Dakota) that may affect butterfly populations in 
those areas. Finally, we used the Naugle et al. (2011) study and its 
impacts to sage grouse as a surrogate to estimate the impacts of 
similar energy development projects to the butterfly habitat. Because 
the Powder River Basin development varies from the development in the 
Bakken formation, we have corrected our estimations and analysis in 
this final listing rule (see Destruction and Conversion of Prairies to 
Nonagricultural Development, below).
    (137) Comment: A commenter noted that wind energy is not a threat 
to the species in North Dakota. The Service's conclusion that wind 
energy development will expand into the ranges of the Dakota skipper 
and Poweshiek skipperling, and thus is a threat to the species, is 
based on outdated data and is poorly supported. The Service must 
justify its assumptions that wind energy will expand into Dakota 
skipper and Poweshiek skipperling range and consequently be a threat to 
the species.
    Our Response: We have evaluated the stressors to populations at 
sites where we had sufficient information to do so. Generally, we 
consider that wind development will have localized impacts in a few 
sites. We know of at least one site where a proposed wind development 
project poses a threat to the Dakota skipper and its habitat. Another 
wind farm is proposed within 2 miles of areas we proposed as critical 
habitat, with expansion phases that could overlap that critical 
habitat. Both of these projects are in the draft Environmental Analysis 
stage of development. See Destruction and Conversion of Prairies to 
Agricultural Land, below, for a full discussion on impacts from wind 
energy development.
    (138) Comment: The proposed listing determination relies heavily on 
the work of McCabe and Royer for North Dakota, who have both published 
generalized statements about impacts of grazing on the Dakota skipper. 
These authors do not discuss the types of animals, season of use, 
intensity of grazing, or whether a grazing system is involved.
    Our Response: The Service used butterfly surveys and habitat 
reports written by Royer, McCabe, Spomer, and others to inform our 
determination on the status of the species in North Dakota. These 
authors also often reported stressors they observed at sites, such as 
invasive species encroachment or intensive grazing practices. We also 
used other reports and publications to inform the discussion regarding 
grazing effects on the butterflies, which included a discussion 
regarding types of animals, intensity of grazing, habitat type, 
proximity of nearby populations, associated herbicide use, and timing. 
In the conservation guidelines for the Dakota skipper (http://www.fws.gov/midwest/endangered/insects/dask/DASKconservationguidelines2013.html), we further discuss grazing in 
terms of intensity, duration, season of use, and type of habitat.
    (139) Comment: A commenter stated that invasive plant control needs 
to be done very carefully and in small-scale treatments to ensure any 
adverse effects on the Poweshiek skipperling, or the vegetative 
conditions they specifically require, are minimized, as invasive plant 
and brush control is not automatically beneficial to the butterfly. 
Specifically, at the Puchyan Prairie site, there is greater risk of 
unintended negative side effects of invasive plant control on Poweshiek 
skipperlings themselves, or the specific types and structures of 
vegetation they require, than risk of habitat deterioration in the next 
several years, if a more cautious approach is used. More time should be 
allowed to assess and describe the full extent of the kinds of 
microhabitats used by the Poweshiek skipperling, which likely differ 
among years due to climatic variation, and the extent of any change or 
deterioration in the vegetation in their core habitat areas.
    The commenter also stated that the Service is also correct that 
fire management, without careful planning, may have significant adverse 
effects on these skippers; however, the Service understates the risks 
of fire. A number of areas of good Dakota skipper and Poweshiek 
skipperling habitat have been converted by fire management over the 
last several decades from light agricultural land uses to areas lacking 
the features needed by the butterflies. These converted areas in Iowa, 
Minnesota, and westward have few recent records of either species. Fen 
wetland preserves in Michigan do have recent Poweshiek skipperling 
records, but some of these sites have new, not long-term, fire 
management. The Poweshiek skipperling has not fared well in the working 
landscape; thus, deliberate conservation effort is needed.
    Our Response: We agree that conservation of Poweshiek skipperling 
populations relies on careful implementation of management practices 
that conserve its habitat, while

[[Page 63713]]

minimizing adverse effects to reproduction and survival, including 
invasive species control at the few sites where the Poweshiek 
skipperling remains, such as Puchyan Prairie. As discussed in Factor A. 
The Present or Threatened Destruction, Modification, or Curtailment of 
Its Habitat or Range, below, encroaching invasive plants may replace or 
reduce the coverage of native forbs and grasses used by adults and 
larval butterflies and, therefore, need to be controlled. However, we 
further discuss that control methods (such as fire and herbicide 
spraying) may have their own unintended consequences, such as reduced 
native forbs and grasses and direct mortality of the butterflies, if 
not conducted carefully. Furthermore, various habitat types at these 
sites may respond differently to various types of control treatments. 
Therefore, when considering recovery planning for the species, it will 
be important to continue to individually assess sites to determine the 
need to control invasive species, exercise caution when implementing 
treatments, monitor the response to any treatments over the long-term, 
and refine or modify treatments as needed to get desired outcomes. 
Similarly, assessment and long-term monitoring of the species' needs, 
such as microhabitat use, will help inform conservation efforts at 
specific locations.
    (140) Comment: One commenter recommended that land managers be 
advised as to the appropriateness of prescribed burns in Poweshiek 
skipperling habitat.
    Our Response: The Service contacted all of the landowners within 
proposed critical habitat designations as part of this rulemaking 
process. We have developed conservation guidelines for the Dakota 
skipper (online at http://www.fws.gov/midwest/endangered/insects/dask/DASKconservationguidelines.html), and are developing similar guidelines 
for Poweshiek skipperling. Contact the Service's Ecological Services 
Field Office in your State to discuss prescribed burn practices on land 
where one or both species may be present.
    (141) Comment: One commenter recommended that sites with Dakota 
skipper populations where fire management is not already occurring 
should remain fire-free, and that fire management should cease in core 
habitat for the Dakota skipper. Instead, cautious rotational haying or 
grazing regimes should be used to rehabilitate grassland vegetation to 
the shorter turf height that Dana (1991) recommends for the species.
    Our Response: We have developed conservation guidelines for the 
Dakota skipper (http://www.fws.gov/midwest/endangered/insects/dask/DASKconservationguidelines.html), and are developing similar guidelines 
for Poweshiek skipperling. The recommendations will be reviewed for 
possible incorporation as we continue to refine these guidelines.
    (142) Comment: A commenter noted that the proposed rule states that 
the negative effects of fire persist for 1 to 5 years, citing Swengel 
(1996, pp. 73, 79, 81) and Panzer (2002, pp. 1302-3). These papers, 
however, include a range of butterfly species found in prairies, not 
just localized prairie specialists like the Dakota skipper and 
Poweshiek skipperling. Panzer's study contains no data on the Poweshiek 
skipperling or Dakota skipper. Swengel (1996) includes specific 
analysis of both species, but no explicit predictions are made. Swengel 
(1996, pp. 73, 79) describes that the negative effects of fire persist 
for specialists for 3 to 5 or more years. Swengel (1996) does not 
indicate an expectation of recovery 1-2 years post-burn for these 
species. Thus, Swengel's analysis is better used to define when 
recovery has certainly not occurred (within years 0-3), but not when 
recovery actually has occurred.
    Our Response: We corrected our interpretation of the Swengel (1996) 
and the Panzer (2002) papers as discussed under Factor A. The Present 
or Threatened Destruction, Modification, or Curtailment of Its Habitat 
or Range, below, to better reflect the included data and information. 
We also changed our use of the word ``recovery'' in this context to the 
term ``rebound,'' which more accurately describes an upward trend, but 
does not imply a stable recovered trend in populations.
    (143) Comment: A commenter noted that Dana (1991, pp. 55-56) 
discusses concern about grass growth structure and height, namely that 
fire encourages taller grass growth, but that Dakota skippers prefer 
shorter grass. Therefore, effectively controlling weeds and brush does 
not necessarily mean that the management is creating suitable habitat 
for skippers. In the long run, fire does not produce a suitable 
vegetative structure for skippers. The long-term compounding indirect 
effect of fire on the vegetation (increasing grass height and 
thickness) may have a more lasting impact on the species and be more 
difficult to manage.
    Our Response: We will consider the longterm effect of fire on 
native vegetation growth and structure when developing and refining 
conservation guidelines for the Dakota skipper and Poweshiek 
skipperling.
    (144) Comment: The data used for North Dakota in the proposed 
listing rule relies heavily on the work of McCabe and Royer, who have 
both published generalized statements about grazing and its effects on 
the Dakota skipper. These authors do not discuss the types of animals, 
season of use, intensity of grazing or whether a grazing system is 
involved.
    Our Response: The Service relied on butterfly surveys and habitat 
reports written by Royer, McCabe, Spomer, and others to inform species 
and habitat data in North Dakota. These authors also often reported 
stressors they observed at sites, such as invasive species encroachment 
or intensive grazing practices. We used various other reports and 
publications to inform the discussion regarding grazing in Factor A of 
this final listing rule and included a discussion regarding types of 
animals, intensity of grazing, habitat type, proximity of nearby 
populations, associated herbicide use, and timing. In our conservation 
guidelines for Dakota skipper, we further discuss grazing in terms of 
intensity, duration, season of use, and type of habitat.
    (145) Comment: A commenter noted that low-intensity grazing is 
mentioned as a potential management tool to help maintain habitat and 
abate other threats to these two species. In some cases, high-
intensity, short-duration grazing may have a role in providing the 
disturbance that prairies require to prevent them from being overrun by 
woody plants, and invasive species.
    Our Response: We have developed conservation guidelines for the 
Dakota skipper's specific needs. These guidelines include some grazing 
recommendations; however, we are interested to learn more details about 
the effects of grazing practices implemented in various areas as we 
continue to refine our recommendations, and will take this information 
into consideration.
    (146) Comment: A commenter noted that data suggest Poweshiek 
skipperling populations at sites that were hayed prior to preservation 
did not recover to the same level following any subsequent fire.
    Our Response: We acknowledge that fire management may be 
detrimental to the Poweshiek skipperling, if not conducted properly. We 
are developing conservation guidelines for the Poweshiek skipperling 
that will address fire management and other actions, and are interested 
to learn more about the implications of fire practices as we continue 
to develop and refine our conservation recommendations.

[[Page 63714]]

    (147) Comment: A commenter stated that the Service should provide 
data to support that fire management, even if applied to most or all of 
the patch occupied by the Dakota skipper or Poweshiek skipperling, has 
a low effect on the long-term persistence of these populations. The 
Service does not cite long-term studies of impacts from fire, but 
instead provides a list of assumptions, such as the following: (1) Fire 
happens in prairie (although the extent of that in a natural context is 
open to great debate; see literature review in Swengel and Swengel 
2007, p. 264); (2) these skippers live in prairie; (3) fire has various 
effects on prairie plants (although it should not be assumed that fire 
controls brush and weeds; see Swengel et al. 2011, p. 535); (4) those 
floristic effects are assumed to be beneficial to these skippers 
(although vigorous tall grass growth caused by fire may not be; see 
Dana 1991, pp. 5-56). Based on these assumptions, the Service concludes 
that fire should be fine for these skippers. The Service needs to 
provide direct positive evidence indicating that the skippers, 
especially the larvae, actually succeed in the long term following a 
fire.
    Our Response: We will consider all factors and data regarding the 
effects of fire on the species during recovery planning and 
implementation and in developing and refining the conservation 
guidelines for these two species. We acknowledge that there are no 
long-term (more than two decades) studies of fire management that 
provided data showing long-term persistence of the populations. We 
based our threats analysis and ranking of stressors as high, medium, 
and low based on the studies cited in our discussion of impacts from 
fire under the Summary of the Factors Affecting the Species section of 
this final rule, below. The possibility that we may have underestimated 
the stressors of fire management on the species further supports our 
determinations that fire can be a significant stressor to populations 
of Poweshiek skipperlings.
    (148) Comment: A commenter stated that there are problems with some 
reports that use McCabe's 1981 management recommendations, because 
McCabe's paper reflects a point-in-time. Prairie ecology requires long-
term observations and knowledge of how past and current management 
activities impact plant community dynamics. Further, prairie management 
conclusions based upon observations made in 1981 are no longer valid, 
due to changes in ecological drivers caused by broad-scale invasion of 
exotic cool-season grasses and forbs.
    Our Response: McCabe's 1981 report is used as a reference to 
prairie conditions prior to much habitat degradation or exotic species 
invasions that are common in many locations today. We acknowledge that 
an understanding of prairie ecology requires long-term observations, as 
well as knowledge of how past and current management activities have 
impacted and continue to impact plant community dynamics.
    (149) Comment: One commenter agreed that annual haying on or after 
August 1 presents little or no stress to Dakota skippers. However, the 
commenter went on to point out that Swengel (1998b) found that 
Poweshiek skipperling abundance was strongly correlated with increasing 
number of years since the last management action, of any management 
type, including haying. Thus, annual haying of the entire habitat patch 
should be considered a high stressor for the Poweshiek skipperling. The 
Service is correct that alternate-year haying is better than annual 
haying, but it's even better when the haying is done rotationally (half 
per year, instead of all every other year). Additionally, the moderate 
stressor category for haying is confusing. As it currently reads, a 
site could fall in the moderate category because you do not know the 
timing of the haying, but if you did know the timing, you would place 
it in the high category.
    Our Response: We developed the stressor categories for the purposes 
of the threats analysis to inform our listing determinations; these 
categories are not intended to be prescriptive conservation measures or 
guidelines. We acknowledge that there is some uncertainty in the 
`moderate' stressor category for haying, but we wanted to fairly 
capture sites where we were unsure of the timing of haying activities, 
but that showed signs indicative of reduced nectar sources. It is true 
that these sites could be moved into the low or high category if we 
received more specifics on the timing of haying in those locations, and 
those details will be more important during the recovery planning 
stages for these species.
Factor B
    (150) Comment: A commenter noted that recent publications report 
that nonlethal sampling of genetic material adds an immeasurable or 
minor effect on survival or reproductive success of butterflies 
compared to handled individuals that were not also genetically sampled 
(Marschalek et al. 2013; Crawford et al. 2013). However, there is 
abundant literature on how handling has adverse effects on butterflies, 
documented for a wide range of species (e.g., Benson and Emmel 1973; 
Singer and Wedlake 1981; Lederhouse 1982; Morton 1984). It is possible 
that some types of nonlethal sampling do not significantly increase the 
harm to the butterfly from capture and handling, but the handling for 
such sampling still causes harm compared to the butterfly not being 
handled. Thus, the benefits of such sampling should be weighed against 
the harm caused to individuals.
    Our Response: As stated under Factor B of this final rule, handling 
stress during scientific study may affect individuals of both species. 
Adverse effects on butterflies have been documented for a wide range of 
species (e.g., Benson and Emmel 1973, p. 329; Singer and Wedlake 1981, 
pp. 215-216; Lederhouse 1982, pp. 381-382; Morton 1984, pp. 56-57; 
Mallet et al. 1987, pp. 380-383). The Service will consider stress and 
other impacts to the butterflies from handling when issuing scientific 
permits for genetic sampling and other sampling efforts.
    (151) Comment: A commenter noted that reliably effective captive 
propagation has not been demonstrated for either of these species. 
However, the Service should consider and assess the effect on wild 
populations of either species before attempting to develop captive 
propagation.
    Our Response: The Service will consider incidental take for 
otherwise legal activities in our permitting (e.g., section 10 recovery 
permits) process.
Factor D
    (152) Comment: A commenter stated that as of August 2013, the 
Minnesota Department of Natural Resources listed both the Dakota 
skipper and the Poweshiek skipperling as endangered. The Dakota skipper 
is also an ``endangered'' species under Iowa law.
    Our Response: We have updated the State-level protections for 
Dakota skipper and Poweshiek skipperling in Factor D of this final 
listing rule.
Factor E
    (153) Comment: A commenter stated that herbicides applied in 
skipper habitat can negatively affect nectar resources for the species. 
However, herbicide use can have benefits if carefully targeted to 
treating brush and weeds, so long as bare ground does not subsequently 
result from the treatment, as bare ground greatly facilitates 
recruitment of new weed and brush growth.
    Our Response: We acknowledge that carefully targeted herbicide 
treatments

[[Page 63715]]

may result in the beneficial control of nonnative or invasive plants 
and brush, and have clarified our statements in Factor E of this final 
listing rule, below.
    (154) Comment: A commenter noted that results of a preliminary 
analysis of the genetic diversity of the Poweshiek skipperling show 
limited levels of genetic diversity in the Wisconsin, Michigan, and 
Manitoba populations. Demographic factors are of greater concern, 
specifically, small population sizes and numbers of populations are 
more likely to lead to extinction than loss of genetic diversity. The 
widespread and intensive survey effort showing continual extirpation of 
populations and reduced population sizes supports the listing of 
Poweshiek skipperling as endangered.
    Our Response: We have incorporated information from the preliminary 
results of Saarinen (2013, pers. comm.) under Factor E. Other Natural 
or Manmade Factors Affecting Its Continued Existence, in the discussion 
on Habitat Fragmentation and Population Isolation, below, and look 
forward to receiving final results from this research to inform future 
conservation efforts for this species.
    (155) Comment: A commenter stated that weather and climate events, 
such as the persistent drought in the Midwest, and their effects on the 
Dakota skipper and Poweshiek skipperling require further study. Funding 
and staff are needed to accomplish these efforts.
    Our Response: In this rule, we used the best available information 
on climate and climate change, however we agree that more study of 
weather and climate events will help us with recovery planning and 
implementation for these two species, and will consider new information 
when developing the recovery plan.
    (156) Comment: A commenter stated that, in its assessment of 
impacts to the butterflies from climate change, the Service ignores 
model uncertainty that the Intergovernmental Panel on Climate Change 
(IPCC) acknowledges.
    Our Response: We appreciate your comment and understand that there 
are uncertainties in the climate modeling. We consider climate change 
to be a potential threat to the species, while acknowledging 
uncertainty of how changes may specifically impact these species or 
their habitats.
    (157) Comment: A commenter stated that, while it is possible that 
unknown threats to the species exist, it is inappropriate to focus too 
much effort on the search for unknown stressors. This distracts from 
addressing the challenges of dealing with the stressors that have been 
known for decades (isolated populations in fragmented habitats that are 
under pressure from habitat degradation and land management practices).
    Our Response: We acknowledge that multiple stressors are acting on 
populations of both species, and have been so for many years. In our 
review, however, it appears that many sites with known populations of 
the Poweshiek skipperling appear to have simultaneously declined to 
undetectable levels. A similar, but perhaps delayed, decline is being 
observed in Dakota skipper populations. We did not want to rule out the 
possibility that this decline may be due to some unknown cause. 
However, we will focus on all potential factors affecting the species 
in recovery planning and implementation, not simply on any single 
factor.
Determinations
    (158) Comment: A commenter stated that the Dakota skipper and 
Poweshiek skipperling are both threatened by loss of native prairie 
vegetation to agriculture, development, altered fire patterns, and 
groundwater depletion. The Dakota skipper and Poweshiek skipperling are 
also threatened by pesticides, drought, and climate change. In light of 
the population declines and ongoing threats, both butterflies should be 
protected as endangered rather than as threatened.
    Our Response: The Dakota skipper is experiencing population 
declines and facing multiple threats. A few populations in the United 
States are doing relatively well, however, and are in habitats that 
have low or non-immediate threats. Furthermore, Canada has an estimated 
15 populations on lands that are being utilized in a manner conducive 
to the conservation of Dakota skipper, and the threats at those sites 
are not imminent. Based on our review of the best available scientific 
and commercial information, we conclude that the Dakota skipper is 
likely to become in danger of extinction in the foreseeable future 
throughout all of its range and, therefore, meets the definition of a 
threatened species. For a detailed discussion, see the Determination 
section of this final rule, below.
    (159) Comment: A commenter stated that the Service should list the 
Dakota skipper as endangered, as it is ``in danger of extinction 
throughout all or a significant portion of its range.'' The species is 
present at 91 sites, at least 83 ``are subject to one or more threats 
that have a moderate to high impact on those populations.'' The Service 
does not explain why 8 sites that are presumably secure outweigh 83 
sites that are experiencing moderate to high threat levels, especially 
since ``Dakota skipper . . . habitat is highly fragmented and because 
the species are subject to local extinction . . . and approximately 84 
percent of Dakota skipper sites with present or unknown status are 
effectively isolated.''
    Our Response: We agree that the Dakota skipper is imperiled, which 
is why we determined that the species warrants listing under the Act. 
However, we believe that the Dakota skipper is not in immediate danger 
of going extinct at this point in time. Instead, we believe that, if 
trends continue as they currently are, the species is likely to get to 
that point in the foreseeable future. Because there are stable 
populations of the Dakota skipper that do not appear to be currently 
suffering from high-magnitude threats, and the declining trends are 
happening at a slower pace, we determined that threatened species 
status is appropriate for the Dakota skipper (see Determination, below, 
for a full discussion).
    (160) Comment: A commenter stated that the Service determines that 
the Dakota skipper is a threatened species because ``Canada has a fair 
number of populations that are being managed in a manner conducive to 
the conservation of Dakota skipper, and the threats at those sites are 
not imminent.'' A ``fair number'' is not a biologically meaningful 
measure. The Service needs to explain this contention in a measurable 
manner.
    Our Response: We are aware of 14 sites in Canada where the species 
is considered to be present and one site where the occupancy is 
unknown. Those sites are managed by late-season haying (after August 1) 
that is conducted at least every other year, and there is no indication 
that native plant diversity is declining due to timing or frequency of 
mowing.
    (161) Comment: A commenter stated that the Canadian populations are 
functionally isolated from each other and from U.S. populations. The 
distance between all these metapopulations makes interaction or 
recolonization unlikely, as Dakota skippers may be incapable of moving 
greater than 1 km (0.6 mi) between patches of prairie habitat separated 
by structurally similar habitats. The Service did not conduct an 
adequate analysis of ``significant portion of range,'' to determine if 
the three metapopulations (U.S., Manitoba, and Saskatchewan) should 
each be considered ``significant,'' and if one is ``in danger of 
extinction,'' then the species as a whole should be listed as 
endangered. The Service must

[[Page 63716]]

separately analyze threats to each isolated metapopulation because 
population isolation and accompanying loss of genetic diversity are 
acknowledged to have significant impacts on the species.
    Our Response: Under the Act and our implementing regulations, a 
species may warrant listing if it is endangered or threatened 
throughout all or a significant portion of its range. Because we have 
determined that the Dakota skipper is a threatened species throughout 
all of its range, no portion of its range can be ``significant'' for 
purposes of the definitions of ``endangered species'' and ``threatened 
species.'' See the Final Policy on Interpretation of the Phrase 
``Significant Portion of Its Range'' in the Endangered Species Act's 
Definitions of ``Endangered Species'' and ``Threatened Species'' (79 FR 
37577, July 1, 2014).
    (162) Comment: A commenter stated that the Service has an 
obligation to make available the studies that form the basis of its 
action. The Service failed to provide any materials other than its own 
draft species assessment and textual descriptions of proposed critical 
habit for either the proposed listing or critical habitat designation 
in the regulations.gov docket or on its Web sites. The Service did 
provide a bibliography; however, many references cited were unpublished 
reports or internal documents.
    Our Response: One element of the transparency and open government 
directive encourages executive departments and agencies to make 
information about operations and decisions readily available to the 
public. Supporting documentation used to prepare the proposed and final 
rules is available for public inspection, by appointment, during normal 
business hours, at the U.S. Fish and Wildlife Service, Twin Cities 
Ecological Services Field Office, 4101 American Boulevard East, 
Bloomington, Minnesota 55425.
4(d) Rule
    (163) Comment: One commenter said that the 4(d) rule proposed for 
the Dakota skipper should be extended to remove prohibitions for take 
incidental to lawfully conducted oil and gas operations and that this 
would not undermine the goal of promoting the healthy growth of these 
populations throughout their entire range. The commenter indicated that 
the activities that were addressed by the proposed 4(d) rule--a variety 
of routine livestock ranching activities and mowing of recreational 
trails--were far more widespread in the region and contribute more 
directly to the threats listed in the proposed rule than were oil and 
gas related activities.
    Our Response: Although livestock ranching activities and mowing of 
recreational trails may be more widespread throughout the species 
range, livestock grazing also can be a key factor in the conservation 
of Dakota skipper habitat, by helping to ensure that the species' 
habitats are not subjected to activities that result in their permanent 
destruction. That is, lands are likely to remain unplowed as long as 
the landowner chooses to continue to use them for grazing. In addition, 
grazing may also be implemented in a manner that provides significant 
benefits to the species. In these ways oil and gas production and 
grazing are fundamentally different with respect to Dakota skipper 
conservation. Regardless, the Service recognizes that a variety of 
interests, including oil and gas activities, may hold the potential to 
contribute to Dakota skipper conservation.
    (164) Comment: One commenter stated that the 4(d) rule would 
provide an important incentive to continue late-summer haying where 
that practice is currently being implemented.
    Our Response: We agree that the 4(d) rule will provide this 
incentive, as intended. Late-summer haying is currently the primary 
management on numerous sites inhabited by Dakota skipper that are 
important for the species' conservation.
    (165) Comment: One commenter requested that we also exempt take 
caused by ``construction with minimal disturbance, such as that for 
transmission lines, that occurs after July 15th'' in the 4(d) rule. The 
same commenter requested that the Service ``give consideration to 
exempting transmission line maintenance activities and existing right-
of-way maintenance in the same way that section line maintenance is 
exempted in the proposed 4(d) rule.''
    Our Response: It is unclear which populations could be affected by 
these activities, what the effects might be, and how the effects might 
be minimized. Therefore, we have not included these activities in the 
4(d) rule.
    (166) Comment: One commenter stated that ``the proposed 4(d) rule 
will undermine, not advance, conservation of the species'' and that the 
4(d) rule was not needed to prevent habitat destruction because it 
would already be illegal under section 9 of the Act and uninhabited 
areas at risk for conversion would be protected by designating them as 
critical habitat.
    Our Response: It is true that take of Dakota skippers that results 
from destruction of its habitat would be prohibited under section 9 of 
the Act, but there are other reasons to promulgate the 4(d) rule. As we 
stated in the proposed rule, the 4(d) rule will facilitate cooperation 
with private landowners that will be needed to recover the species. 
About 47 percent of the sites where the Dakota skipper has been 
recorded in the United States and that may still harbor the species are 
on private land. Almost all of these sites are working lands managed 
with grazing or haying. Conservation of the Dakota skipper on these 
sites, and in general, will require the Service and other conservation 
agencies and groups to develop and maintain cooperative partnerships 
with private landowners. Without that cooperation, we are unlikely to 
realize the substantial improvements in habitat conditions and public-
private partnerships necessary to conserve the species.
    (167) Comment: A commenter stated that the proposed 4(d) rule does 
not provide details as to how the Service intends to ensure that 
infrastructure, such as corrals, loading chutes, and other livestock 
working facilities, are carefully sited so that impacts to the species 
are minimized.
    Our Response: These types of facilities are unlikely to have 
significant impacts to Dakota skipper populations, except where the 
species has been reduced to only very small areas. In grazed lands that 
are typically inhabited by Dakota skipper, these facilities affect only 
small proportions of the available habitat. Therefore, we do not think 
that the small degree of impact posed by placement of livestock working 
facilities would merit site-specific approval and review by the 
Service. Instead, by foregoing any requirement for landowners to seek 
Service approval for siting these facilities, we are likely to further 
facilitate continued development of positive working relationships that 
will be essential for recovering the species. In addition, we can work 
with landowners on voluntary methods to minimize any impacts that might 
result from installation of facilities associated with grazing.
    (168) Comment: One commenter stated that the protections afforded 
the Dakota skipper through the 4(d) rule are not sufficient to reverse 
the trend toward extinction because they do not ensure that the grazing 
practices exempted under the rule will benefit the Dakota skipper.
    Our Response: It may not be practicable to expect broad 
implementation of specific mandated grazing practices on private land 
to conserve the Dakota skipper without the

[[Page 63717]]

willingness of the landowner to implement those practices. Conservation 
of Dakota skippers on grazed lands will require several steps that 
include the development of site-specific grazing recommendations, 
monitoring the effects of the recommend practices on the Dakota skipper 
and its habitat, and science-based adaptive management. Each step will 
require access to private and other non-Federal lands by persons with 
expertise in identifying and describing the Dakota skipper and its key 
habitat components and, in at least some cases, by grazing experts and 
conservation partners. Landowners and land managers may be less likely 
to grant access for these activities if we broadly mandate specific 
grazing practices. Furthermore, although the incidental take permitting 
process would also provide an avenue by which to work with private 
landowners and is often the best available option for some species, 
there is no clear avenue that is immediately available by which to 
engage the large and geographically widespread group of landowners in 
such a process for Dakota skippers. A permitting process that would 
involve more than a few landowners is likely to take years and would 
have significant potential to become contentious and unwieldy.
    (169) Comment: One commenter suggested that, instead of listing 
counties in which take caused by grazing would not be exempted under 
the 4(d) rule, the Service should base this on habitat.
    Our Response: We decided that it is more appropriate to exempt take 
of Dakota skippers caused by grazing on all non-Federal lands in the 
United States, regardless of geographic area, and have made this change 
in the final 4(d) rule. We recommend, however, that lands where native 
prairie is currently maintained by haying continue to be hayed, and 
that any change to grazing on these lands only be done with the prior 
input from experts in Dakota skippers and range conservation. We 
suggest contacting the Service's Ecological Services Office in your 
State for more information.
    (170) Comment: A commenter asked what areas can be treated for 
weeds or pests and still be exempted by the 4(d) rule.
    Our Response: The 4(d) rule does not address control of animal 
pests; therefore, it does not exempt take that may result from 
treatments that are applied to control animal pests. The 4(d) rule also 
does not exempt take of Dakota skippers that would result from the 
broadcast application of herbicides--that is, application of herbicides 
evenly across all or a portion of an area. Take of Dakota skippers that 
is caused by applications of herbicide that do not meet this definition 
of broadcast spraying would be exempted by the 4(d) rule.
    Take of Dakota skippers is unlikely if they do not inhabit an area 
where broadcast application of herbicides is proposed. If the presence 
of Dakota skippers is suspected in an area where broadcast application 
of herbicides is proposed, we recommend that the Service be contacted 
to determine whether the action may be likely to cause take of the 
species, and if reasonable measures may be adopted that would avoid 
take.

Summary of Changes From the Proposed Rule

    Based on our review of the public comments, comments from other 
Federal and State agencies, peer review comments, issues addressed at 
the public hearing, and any new relevant information that may have 
become available since the publication of the proposal, we reevaluated 
our proposed rule and made changes as appropriate.
    During the comment periods, the Service received additional survey 
information, minor clarifications, and additional information on the 
species biology. New survey information has changed the occupancy 
status at several sites, for example a site that we considered to be 
``unknown'' in the proposed rule may now be considered ``extirpated'' 
due to three sequential years of negative survey data. Consequently, 
some sites were dropped from our analysis of factors affecting the 
species because we no longer consider the species to be present or 
possibly present (unknown) at a particular location. In addition, we 
included new information into our analysis of the factors affecting the 
species. Neither the new information nor the updated occupancy at some 
sites has significantly changed our analyses such that it changed our 
determinations of status under the Act for either species.
    The 4(d) rule now exempts take of Dakota skippers caused by grazing 
on all non-federal lands in the United States; the proposed 4(d) rule 
did not apply to certain lands in Minnesota and North Dakota. The final 
4(d) rule no longer exclude some counties from the part of the rule 
that exempts take caused by grazing. Other minor changes to the 4(d) 
rule include: Clarifying broadcast versus spot-spraying of herbicides; 
defining ``recreational trail''; and, that take of Dakota skipper 
caused by haying in transportation rights-of-ways and corridors after 
July 15 is exempt under the 4(d) rule, as long as it is associated with 
livestock ranching activities. The 4(d) rule exempts take of Dakota 
skippers caused by mowing recreational trails, a term that is defined 
in the rule, even when it is not associated with livestock grazing.

Summary of the Factors Affecting the Species

Factor A. The Present or Threatened Destruction, Modification, or 
Curtailment of Its Habitat or Range

    Habitat quality is a powerful determinant of extinction probability 
in butterflies such as the Dakota skipper and Poweshiek skipperling 
(Thomas et al. 2001, p. 1795). Among butterfly species in the United 
Kingdom, for example, equilibrium density of butterflies at sites with 
optimum habitat are from 25 to more than 200 times greater than those 
for occupied sites with suboptimal, yet suitable, habitat (Thomas 1984, 
cited in Thomas et al. 2001, p. 1794). Consistently good habitat 
quality is especially important for Dakota skipper and Poweshiek 
skipperling isolated populations, which would not be naturally 
recolonized if they were extirpated. Protection or restoration of 
habitat quality at these isolated sites is critical to the survival of 
both species, although stochastic events still pose some risk, 
especially for smaller populations and at small sites.
    The Poweshiek skipperling and Dakota skipper depend on a diversity 
of native plants endemic to tallgrass prairies and, for the Poweshiek 
skipperling in Michigan, prairie fens. When nonnative or woody plant 
species become dominant, Poweshiek skipperlings and Dakota skippers 
decline due to insufficient sources of larval food and nectar for 
adults. For example, at Wike Waterfowl Production Area in Roberts 
County, South Dakota, the extirpation of Poweshiek skipperling is 
attributed to the deterioration of native vegetation, in particular, 
the loss of nectar sources for adult butterflies due to invasive 
species encroachment (Skadsen 2009, p. 9).
    Destruction of native tallgrass and mixed-grass prairie began in 
1830 (Samson and Knopf 1994, pp. 418-419). Extant populations of Dakota 
skipper and Poweshiek skipperling are restricted to native-prairie 
remnants and prairie fens; native prairies have been reduced by 85 to 
99.9 percent of their former area throughout the historical range of 
both species (Samson and Knopf 1994, pp. 418-419). Degradation and 
destruction of habitat occurs in many ways, including but not limited

[[Page 63718]]

to: Conversion of native prairie to cropland or development; ecological 
succession to woody vegetation; encroachment of invasive species; past 
and present fire, haying, or grazing management that degraded or 
destroyed the species' habitats; flooding; and groundwater depletion, 
alteration, and contamination, which are discussed in further detail 
below.
    We evaluated the level of impact to the population at each site of 
several habitat-related stressors at 163 Dakota skipper sites where the 
occupancy status of the site is considered to be present or unknown, as 
defined in the Background section of this final rule (Table 3, above). 
These 163 sites are found across the current range of the species in 
Minnesota, North Dakota, and South Dakota. Eight sites with an unknown 
or present occupancy were not evaluated. To determine the levels of 
impact to the population at each site, we used the best available and 
most recent information for each site, including reports, discussions 
with site managers, information from natural heritage databases, etc. 
(Service 2012, unpubl. data; Service 2014, unpubl. geodatabase). We 
only evaluated a stressor to the population at any one site if we had 
sufficient information to determine if the level of impact was high, 
medium, or low as defined for each stressor below. Similarly, the level 
of impact to the population was evaluated at 60 Poweshiek skipperling 
sites with present or unknown status (Table 4). Although we did not 
evaluate Factor A stressors at all 87 Poweshiek skipperling sites with 
present or unknown occupancy, the 60 sites that were evaluated are 
representative of all the present or unknown Poweshiek skipperling 
sites in terms of geography (range of the species, i.e., sites in Iowa, 
Michigan, Minnesota, North Dakota, South Dakota, and Wisconsin were 
evaluated), ownership, and management. Many sites for both species (58 
sites for Dakota skipper and 26 sites for Poweshiek skipperling) 
experience at least two habitat-related stressors at a medium or high 
level of impact (Tables 3 and 4).

 Table 3--Number of Dakota Skipper Sites With Each Level of Impact and the Total Number of Sites That Were Rated
    for Each Type of Stressor. A Total of 163 Dakota Skipper Sites With Either Present or Unknown Status Were
     Examined; Only Sites With Sufficient Data for a Particular Stressor Were Rated as High, Medium, or Low
                         [Service 2012 Unpubl. data; Service 2014, unpubl. geodatabase]
----------------------------------------------------------------------------------------------------------------
                                                  High level  of   Medium level    Low level  of   Total number
                    Stressor                          impact         of impact        impact      of rated sites
----------------------------------------------------------------------------------------------------------------
Destruction & Conversion (Agricultural &                       3              83              58             144
 Nonagricultural Development)...................
Wind Development................................               1               0               8               9
Flooding........................................               2               6               6              14
Invasive Species................................              12              33              20              65
Fire............................................              10               4               6              20
Grazing.........................................               9              29              14              52
Haying & Mowing.................................               1              11              29              41
Lack of Management..............................               9               5               3              17
Size/Isolation..................................              50              50              63             163
Herbicide and/or Pesticide Use..................               5               2               8              15
----------------------------------------------------------------------------------------------------------------


Table 4--Number of Poweshiek Skipperling Sites With Each Level of Impact and the Total Number of Sites That Were
Rated for Each Type of Stressor. A Total of 60 Poweshiek Skipperling Sites With Either Present or Unknown Status
   Were Examined; Only Sites With Sufficient Data for a Particular Stressor Were Rated as High, Medium, or Low
                               [Service 2012 unpubl.; Service 2014, unpubl. data]
----------------------------------------------------------------------------------------------------------------
                                                   High level of   Medium level    Low level of    Total number
                    Stressor                          impact         of impact        impact      of rated sites
----------------------------------------------------------------------------------------------------------------
Destruction & Conversion (Agricultural &                       2              11              28              41
 Nonagricultural Development)...................
Wind Development................................               0               0               5               5
Flooding/Hydrology..............................               2               3              14              19
Invasive Species................................               6              29              11              46
Fire............................................               4               2              10              16
Grazing.........................................               4              10               2              16
Haying & Mowing.................................               0               3               3               6
Lack of Management..............................               4               6               2              12
Size/Isolation..................................              21              22              11              54
Herbicide and/or Pesticide Use..................               3               1               5               9
----------------------------------------------------------------------------------------------------------------

Destruction and Conversion of Prairies

Destruction and Conversion of Prairies to Agricultural Land

    Conversion of prairie for agriculture may have been the most 
influential factor in the decline of the Poweshiek skipperling and 
Dakota skipper since Euro-American settlement, but the impacts of such 
conversion on extant populations is not well known. By 1994, tallgrass 
prairie had declined by 99.9 percent in Illinois, Iowa, Indiana, North 
Dakota, Wisconsin, and Manitoba; and by 99.6 percent in Minnesota; and 
85 percent in South Dakota (Samson and Knof 1994, p. 419). Samson and 
Knof (1994, p. 419) did not provide a figure for the decline of 
tallgrass prairie in Saskatchewan, but mention an 81.3 percent decline 
in mixed grasses from historical levels. By 1994, mixed-grass prairie 
had declined from historical levels by 99.9 percent in Manitoba and

[[Page 63719]]

71.9 percent in North Dakota (Samson and Knof 1994, p. 419). 
Destruction of tallgrass and mixed-grass prairie began in 1830, but 
significant documentation of the ecosystem's butterfly fauna did not 
begin until about 1960. Therefore, most of the decline of the Dakota 
skipper and Poweshiek skipperling probably went unrecorded.
    Since about 1980, observers have documented the extinction of 
several populations of the Dakota skipper and Poweshiek skipperling due 
to habitat conversion to agricultural use in the United States and 
Canada. For example, four Dakota skipper sites in North Dakota were 
converted to irrigated potato fields, and one in South Dakota was 
converted for crop production (Royer and Marrone 1992a, p. 17). The 
Fannystelle site in Manitoba, where the Dakota skipper was last 
recorded in 1991, was subsequently converted for row-crop agriculture 
(Webster 2003, p. 7). In North Dakota, further conversion is a stressor 
to Dakota skippers in the important Towner-Karlsruhe complex (Royer and 
Royer 1998, p. 22; Lenz 1999, p. 13), where the flat topography and 
high water table facilitate conversion to irrigated crop production. 
Populations of Dakota skipper in Manitoba typically occupy flat terrain 
that may be vulnerable to conversion to cropland, although soil 
conditions may be unsuitable for row crops at some of these sites 
(Webster 2003, p. 10). Similarly, conversion of native prairie to 
cropland continues to be a threat to Poweshiek skipperling habitat 
throughout its range (Royer and Marrone 1992b, p. 17).
    The Dakota skipper, and until recently, the Poweshiek skipperling, 
have largely persisted in areas that are relatively unsuitable for row 
crop agriculture because of their steep terrain (e.g., in the Prairie 
Coteau of South Dakota) or where soils are too wet or rocky for row-
crop agriculture (McCabe 1981, pp. 189-190, Webster 2003, p. 10). 
Densely spaced, large glacial rocks, for example, may have deterred 
cultivation at the Chippewa Prairie in Minnesota and ``spared Chippewa 
Prairie in Minnesota from the plow'' (Dana 2012, pers. comm.). In areas 
where Poweshiek skipperling and Dakota skipper habitat persists but is 
adjacent to agriculture, added nutrients from agricultural runoff 
affects groundwater and additional nutrients in the system contribute 
to the dominance of invasive plants (Fiedler and Landis 2012, p. 51: 
Michigan Natural Features Inventory 2012, p. 4).
    In summary, conversion for agriculture on lands suitable for such 
purposes is a current, ongoing stressor of high level of impact to the 
Poweshiek skipperling and Dakota skipper populations in areas where 
such lands still remain. Advances in technology may also increase the 
potential of conversions in areas that are currently unsuitable for 
agriculture.
    We rated the level of impact to the populations of the stressor 
posed by habitat destruction or conversion for both agriculture and 
nonagricultural purposes (except for conversion for wind energy 
development, which was analyzed separately) at 144 Dakota skipper and 
41 Poweshiek skipperling sites with present or unknown status (see 
Tables 3 and 4) where we had sufficient information to evaluate the 
stressor. In our evaluation of this stressor, we combined agricultural 
and nonagricultural impacts--our analyses are discussed below (see 
Destruction and Conversion of Prairies due to Nonagricultural 
Development).

Destruction and Conversion of Prairies to Nonagricultural Development

    Conversion of prairie for nonagricultural land uses, such as energy 
development, gravel mining, transportation, and housing are stressors 
to both Poweshiek skipperling and Dakota skipper populations. For 
example, a site where the Dakota skipper and Poweshiek skipperling were 
recorded in 1997 (Skadsen 1997, pp. 15-16, B-1) in the Bitter Lake area 
of Day County, South Dakota, is now a gravel pit, and the species' 
habitat no longer exists there (Skadsen 2003, pp. 47-48).
    Almost all prairie remnants with Poweshiek skipperling and Dakota 
skipper populations are associated with gravelly glacial till soils 
(Service 2014, unpubl. geodatabase); therefore, gravel mining is a 
potential stressor to populations at a large number of sites. Gravel 
mining is a stressor to Poweshiek skipperling and Dakota skipper 
populations at several sites in Minnesota (Dana 1997, p. 15). For 
example, gravel mining is a stressor in at least three of the five 
sites that comprise the Felton Prairie complex (Cochrane and Delphey 
2002, pp. 16-17); however, the Clay County Stewardship Plan (Felton 
Prairie Stewardship Committee 2002) may have reduced the likelihood of 
the gravel mining stressor to populations at this complex. On at least 
seven sites in Minnesota, Dakota skippers inhabit northern dry prairie 
plant communities, which are generally impacted by gravel mining due to 
the predominance of gravel soils (Minnesota DNR 2006, p. 221). Gravel 
mining is a stressor to populations of Dakota skipper in central 
Manitoba (Rigney 2013a, p. 28). Gravel mines are considered a stressor 
with a high level of impact to populations of both species because, 
where it occurs, the habitat is completely destroyed.
    Potash (salt that contains potassium) mining is a stressor to 
Dakota skipper populations in some Saskatchewan sites (Westwood 2013, 
pers. comm.), although the exact number of sites that are being 
considered for potash mining is unknown and were not included in our 
stressor evaluation.
    Energy development (oil, gas, and wind) and associated roads and 
facilities result in the loss or fragmentation of suitable prairie 
habitat (Reuber 2011, pers. comm.). Major areas of recent oil and gas 
development, such as that occurring in the Bakken formation, overlaps 
with parts of the Dakota skipper's range in North Dakota. North Dakota, 
for example, is now one of the top two oil-producing states in the 
United States, and new development is occurring rapidly (MacPherson 
2012, p. 1; North Dakota Petroleum Council 2012, p. 1). The number of 
drilling permits in North Dakota nearly doubled between 2007 and 2008, 
from 494 permits issued in 2007 to 946 in 2008 (North Dakota Petroleum 
Council 2009, p. 2). Permits dropped to 627 in 2009 (North Dakota 
Petroleum Council 2010, p. 2), but increased dramatically to 1,676 in 
2010 (Ogden 2011, p. 1). While much of the oil activity is currently 
occurring in areas of native prairie overlaying the Bakken and Three 
Forks formations to the west of known locations for both species, 
mineral exploration has occurred in all but one county in North Dakota 
(North Dakota Petroleum Council 2012, p. 1). McKenzie County falls in 
the center of this development and McHenry County is also within these 
formations (Mueller 2013, pers. comm.). The oil development on the 
Bakken formation in North Dakota, for example, may be a future stressor 
to Dakota skipper populations in McKenzie County (Royer and Royer 
2012b, p. 16). Oil production is anticipated to continue to expand at 
record levels (MacPherson 2012, p. 1; MacPherson 2010, entire).
    Native-prairie habitat would be destroyed in the footprint of an 
oil and gas well pad, but the pads are relatively small. However, each 
oil and gas well pad requires new road construction, and evidence 
suggests that Poweshiek skipperlings may avoid crossing roads (Westwood 
et al. 2012, p. 18). Energy development can double the density of roads 
on range lands (e.g., Naugle et al. 2011, pp. 493-494), increase 
pipelines, and increase the number of gravel pits to accommodate the 
increased road construction (Mueller 2013, pers.

[[Page 63720]]

comm.). Development for coal-bed natural gas (as described in Naugle 
2011), for example, in areas with ranching, tillage agriculture, and 
oil and gas development, 70 percent of the developed land was within 
100 m (109 yards (yd)), and 85 percent of the developed land was within 
200 m (218 yd), of a human structure (Naugle et al. 2011, p. 493). 
Researchers estimated that, in those areas, every square km (0.39 
square miles) of land may be both bounded by a road and bisected by a 
power line (Naugle et al. 2011, p. 493). These coal-bed natural gas 
developments can be densely located (e.g., 8 wells per 640 acres) and 
are drilled vertically, whereas shale-oil wells in the Bakken formation 
are drilled horizontally and ``relatively far apart'' (Conoco Phillips 
2013, in litt.). The habitat fragmentation associated with oil and gas 
development may amplify other stressors to both species, such as the 
effects of population isolation and the impacts of stochastic events.
    Energy development has additional undesirable and potentially 
significant cumulative impacts on wildlife. Catastrophic events, such 
as oil and brine spills, could cause direct mortality of Dakota skipper 
or Poweshiek skipperling larvae that are in shelters at or below the 
soil surface. Such spills may also cause the loss of larval host and 
nectar plants in the spill path. Additional plants may be lost during 
spill response, particularly if the response involves burning. The 
likelihood, however, of spills occurring on the small fraction of land 
that remains native tallgrass prairie in North Dakota (less than one 
percent according to Samsom and Knoff 1994, p. 419) is low.
    Wind energy turbines and associated infrastructure (e.g., 
maintenance roads) are likely stressors to Dakota skipper and Poweshiek 
skipperling populations, particularly on private land in South Dakota 
(Skadsen 2002, p. 39; Skadsen 2003, p. 47; Skadsen 2012d, pers. comm.). 
Similar to oil and gas development, wind development would destroy 
native-prairie habitat in the footprint of the structure, add access 
roads and other infrastructure that may further fragment prairies, and 
could be catalysts for the spread of invasive species. Further, it is 
unknown if the noise and flicker effects associated with wind turbines 
may impact Dakota skipper or Poweshiek skipperling populations beyond 
direct impacts from the turbines and/or infrastructure. Other wildlife 
species, such as birds, have shown significant avoidance of grasslands 
where wind development has occurred (Pruett et al. 2009, p. 1256; 
Shaffer et al. 2012,unpaginated). Wind development was assessed at nine 
Dakota skipper sites and six Poweshiek skipperling sites where we had 
sufficient information. The level of threat was considered to be low at 
most sites because, although the site may be in an area with the 
potential for wind development, there are no specific plans or 
proposals to develop wind power on the site.
    Wind development is considered a stressor of high level of impact 
to populations at sites where development is proposed and there are no 
actions or plans to mitigate impacts to the species. For example, a 
wind facility was recently proposed at a Dakota skipper site in South 
Dakota (Skadsen 2012d, pers. comm.), which poses a high-level threat 
for the species at that site because there are no plans to mitigate 
impacts of habitat destruction. Although wind power development 
currently poses a high level of impact to the population at only one 
site, the extent of this stressor will likely increase in the future, 
due to the high demand for wind energy and the number of Dakota skipper 
and Poweshiek skipperling sites that are conducive to wind development 
(e.g., Skadsen 2003, pp. 47-48). Furthermore, power transmission lines 
may be developed in order to accommodate the added power of wind farms, 
for instance, a new power line is currently being planned in the 
Prairie Coteau in South Dakota for that purpose (Mueller 2013, pers. 
comm.).
    Housing construction has likely contributed to the loss of at least 
two Poweshiek skipperling populations in Michigan, and the largest 
extant population in Michigan is located in an area under intense 
development pressure (Michigan Natural Features Inventory 2011, unpubl. 
data). Residential wells and drainage disrupt prairie fen hydrology by 
reducing water levels and, thus, facilitating rapid growth of woody 
vegetation. In addition, nutrients added to the groundwater from 
leaking septic tanks contribute to the dominance of invasive plants, 
such as narrow-leaved cattail (Typha angustifolia) and red canary grass 
(Phalaris arundinacea) (Michigan Natural Features Inventory 2012, p. 
4).
    Road construction impacts Poweshiek skipperling and Dakota skipper 
habitat because it increases the demand for gravel, and impacts also 
result from routine maintenance (e.g., broadcast herbicide 
applications, early mowing, and cleaning out ditches), improvements 
(e.g., widening roads or converting two-lane highways to four-lane 
highways), or new construction. Poweshiek skipperling habitat was 
destroyed or degraded on at least two private properties in Roberts 
County, South Dakota, for example, in association with the widening of 
U.S. Highway 12 (Skadsen 2003, p. 47). Roadside prairie remnants can 
help support populations of both species and serve as dispersal 
corridors between larger remnants; therefore, loss of these areas to 
road expansion or construction further reduces and fragments remaining 
habitat. In Michigan, at least one Poweshiek skipperling site and its 
habitat has been negatively affected by recreational `mud bogging', 
which destroys vegetation and creates conditions conducive to invasive 
species (Hicks 2014, pers. comm.).
    In summary, nonagricultural development, such as gravel mining, 
activities associated with energy development, or housing and road 
development, poses a current stressor of moderate to high impact to 
populations on those lands that are not protected from destruction or 
conversion through a conservation easement or fee title ownership by a 
conservation agency. This type of development may become more 
widespread as such practices increase in the future.
    As discussed above in Destruction and Conversion of Prairies to 
Agricultural Land, we rated the level of impact to the populations of 
the stressor posed by habitat destruction or conversion for both 
agriculture and nonagricultural purposes combined (except for 
conversion for wind energy development, which was analyzed separately) 
at 144 Dakota skipper sites with present or unknown status (see Table 
3) where we had sufficient information to evaluate the stressor. The 
level of impact of each stressor to the population at each site is high 
at three of those sites, due to ongoing destruction of the native 
prairie, or there was a high likelihood of conversion because it is 
located close to other converted areas and the land is conducive for 
agriculture. The level of threat is high at 3 sites, moderate at 83 
sites, and 58 sites are protected from destruction or conversion 
through a conservation easement or fee title ownership by a 
conservation agency (Table 3). This stressor occurs across the range of 
the Dakota skipper; the stressor has a medium to high level of impact 
to Dakota skipper populations in Minnesota, North Dakota, South Dakota, 
Manitoba, and Saskatchewan. The level of impact was considered to be 
low if the site is protected from destruction or conversion by fee 
title ownership by a governmental conservation agency, nongovernmental 
conservation

[[Page 63721]]

organization (e.g., The Nature Conservancy), or educational institution 
(e.g., South Dakota State University). Similarly, 41 Poweshiek 
skipperling sites with present or unknown status were assessed that had 
sufficient information: The level of threat was high at 2 sites and 
moderate at 11 sites, and 28 sites are protected from destruction or 
conversion through a conservation easement or fee title ownership by a 
conservation agency (Table 4). At least 6 of the 12 sites where the 
Poweshiek skipperling is considered to still be present have a medium 
or high risk of conversion. This stressor occurs across most of the 
Poweshiek skipperling range; the stressor has a medium to high level of 
impact to Poweshiek skipperling populations in Iowa, Michigan, 
Minnesota, and South Dakota; the level of impact is low for the species 
at the Manitoba location.

Fluctuating Water Levels

    Flooding is a stressor to Poweshiek skipperlings and Dakota 
skippers at sites where too much of the species' habitat is flooded or 
where patches are flooded too frequently. Poweshiek skipperlings and 
Dakota skippers must either survive flooding events in numbers 
sufficient to rebuild populations after the flood or recolonize the 
area from nearby areas that had not flooded. In addition, the return 
interval of floods must be infrequent enough to allow for recovery of 
the populations between floods. Changes in hydrology resulting from 
wetland draining and development may permanently alter the plant 
community and, therefore, pose a threat to Poweshiek skipperling and 
Dakota skipper due to loss of larval food and nectar sources.
    The Dakota skipper and Poweshiek skipperling are presumed 
extirpated from several sites due to flooding or draining. For example, 
one Dakota skipper site was lost to flooding due to rising water levels 
at Bitter Lake, South Dakota (Skadsen 1997, p. 15). At Whalen Lake Fen 
in Michigan, dredging and channelization disrupted the hydrology of the 
site and the fen has since been invaded by glossy buckthorn and narrow 
leaf cattail; Poweshiek skipperlings are presumed to be extirpated from 
the site (Michigan Natural Features Inventory 2011, unpubl. data). The 
loss of a large area of habitat at two sites in Manitoba, which were 
previously suitable for Dakota skipper, was caused by prolonged 
inundation of water that likely caused larval mortality and mortality 
of suitable nectar and larval food plants (Rigney 2013a, pp. 28, 153). 
In addition, flood protection activities and associated alteration of 
the landscape (e.g., road work that causes changes to overland 
drainage) is a stressor to the species at some sites in Manitoba 
(Rigney 2013a, p. 28).
    Fluctuating water levels are a current stressor to populations 
across both species' ranges. Loss of habitat or direct mortality due to 
fluctuating water levels, such as permanent flooding or wetland 
draining, is a current stressor to populations in at least 14 Dakota 
skipper sites with present or unknown status and 19 Poweshiek 
skipperling sites with present or unknown status. For example, one of 
the three sites with present or unknown status of Poweshiek skipperling 
in Wisconsin, Puchyan Prairie, is subject to flooding--the entire 
prairie portion of the site was submerged in 1993 (Hoffman 2011, pers. 
comm.; Wisconsin DNR 2012, in litt). The number of Poweshiek 
skipperling observed at that site is consistently low. Flooding is a 
likely factor that has contributed to the low numbers observed in at 
least part of this site (Borkin 2012c, pers. comm.).
    Conversely, groundwater disruption and draining is a stressor at 
all 9 of the Michigan prairie fen Poweshiek skipperling sites where the 
species is present and high at one site with unknown occupancy. 
Interrupted groundwater flow-through fens can reduce water levels and 
facilitate woody vegetation establishment and growth (Michigan Natural 
Features Inventory 2012, p. 4). Agricultural and residential drains and 
wells can lower the groundwater table, thereby reducing the supply of 
calcareous seepage, which is an essential underlying component of 
prairie fen hydrology (Michigan Natural Features Inventory 2012, p. 4). 
Furthermore, nutrient additions associated with drain fields can 
contribute to invasive species encroachment. For instance, if 
groundwater flow to prairie wetlands is severed, fen habitats may 
convert from native grasses and flowering forbs to habitats dominated 
by invasive species or woody vegetation (Fiedler and Landis 2012, p. 
51, Michigan Natural Features Inventory 2012, p. 4). The site with the 
highest number of Poweshiek skipperlings in Michigan, for instance, is 
partially bordered by residential areas and is under intense 
development pressure (Michigan Natural Features Inventory2011, unpubl. 
data). At least 8 of the 11 fen sites with present or unknown status 
are at least partially unprotected from development, and at least 7 of 
those are closely bordered by roads, agriculture, or residential 
developments (Michigan Natural Features Inventory 2011, unpubl. data; 
Service 2014, unpubl. geodatabase). The status of Poweshiek skipperling 
is unknown at one fen site where the hydrology was likely disrupted by 
roads and extensive residential development in close proximity to the 
fen (Michigan Natural Features Inventory 2011, unpubl. data).
    The level of impact to populations due to flooding was assessed at 
12 Dakota skipper sites with present or unknown status that had 
sufficient information to evaluate the stressor (Table 3); this 
evaluation only included sites in North and South Dakota. Flooding is a 
stressor of moderate-level impact to populations at 6 of the sites, 
where there is evidence of recent or pending decrease in the quality or 
extent of suitable habitat at the site due to a change in wetland 
vegetation, wetland hydrology, or flooding--all of these sites occur in 
North Dakota (Service 2012 unpubl. data; Service 2014, unpubl. data). 
Similarly, we assessed 19 Poweshiek skipperling sites with present or 
unknown occupancy for the level of impact to populations due to water 
fluctuations (e.g., flooding or draining) where we had sufficient 
information to evaluate the stressor (Table 4). Water fluctuations is a 
stressor with moderate impact to the populations at 3 Poweshiek 
skipperling sites (including a site in Wisconsin--one of the 12 
Poweshiek skipperling sites with a present status), and changes to 
hydrology is a stressor of moderate- to high-level impact to 
populations at all 11 Michigan sites (including 9 of 12 Poweshiek 
skipperling sites that have a present status) and 1 site in North 
Dakota (Service 2012 unpubl. data; Service 2014, unpubl. geodatabase).
    In summary, fluctuating water levels is a current and ongoing 
stressor of moderate level of impact to populations where the habitat 
may be temporarily lost due to intermittent flooding and is a stressor 
of high severity where a change in hydrology may completely degrade the 
habitat quality of a site, particularly prairie fens.

Invasive Species and Secondary Succession

    Poweshiek skipperlings and Dakota skippers typically occur at sites 
embedded in agricultural or developed landscapes, which make them more 
susceptible to nonnative or woody plant invasion. Nonnative species 
including leafy spurge, Kentucky bluegrass, alfalfa, glossy buckthorn, 
smooth brome, purple loosestrife (Lythrum salicaria), Canada thistle 
(Cirsium arvense), reed canary grass, and others, have invaded 
Poweshiek skipperling and Dakota skipper habitat throughout their 
ranges

[[Page 63722]]

(Orwig 1997, pp. 4, 8; Michigan Natural Features Inventory 2011, 
unpubl. data; Skadsen 2002, p. 52; Royer and Royer 2012b, pp. 15-16, 
22-23). Kentucky bluegrass and leafy spurge (and the persistent efforts 
for chemical control of leafy spurge) have been cited as one of the 
major stressors to native-prairie habitat at several public and 
privately owned Dakota skipper sites in North Dakota (Royer and Royer 
2012b, pp. 15-16, 22-23; Royer 2012, pers. comm.; Royer 2013, pers. 
comm.). Once these plants invade a site, they replace or reduce the 
coverage of native forbs and grasses used by adults and larvae of both 
butterflies. Leafy spurge displaces native plant species, and its 
invasion is facilitated by actions that remove native plant cover and 
expose mineral soil (Belcher and Wilson 1989, p. 172). The seasonal 
senescence patterns (timing of growth) of grass species as they relate 
to the larval period of Dakota skippers determine which grass species 
are suitable larval host plants. Exotic cool-season grasses, such as 
Kentucky bluegrass and smooth brome, are available when Dakota skipper 
and Poweshiek skipperling larvae begin feeding; however, the morphology 
and growth habit of these grasses are likely major determinants of 
their unsuitability to support Dakota skippers (Dana 1991, pp. 46-47). 
Thus, a prevalence of these grasses reduces food availability for the 
larvae.
    The stressor from nonnative invasive herbaceous species is 
compounded by the encroachment of woody species into native-prairie 
habitat. Glossy buckthorn and gray dogwood encroachment, for example, 
is a major stressor to Poweshiek skipperling populations at the Brandt 
Road Fen in Michigan, which supports the second largest population of 
Poweshiek skipperlings in the State (Michigan Natural Features 
Inventory 2011, unpubl. data). Invasion of tallgrass prairie and 
prairie fens by woody vegetation such as glossy buckthorn reduces light 
availability, total plant cover, and the coverage of grasses and sedges 
(Fiedler and Landis 2012, pp. 44, 50-51). This in turn reduces the 
availability of both nectar and larval host plants for Poweshiek 
skipperlings and Dakota skippers. If groundwater flow to prairie 
wetlands is disrupted (e.g., by development) or intercepted (e.g., 
digging a pond in adjacent uplands or installing wells for irrigation 
or drinking water), it can quickly convert to shrubs or other invasive 
species (Fiedler and Landis 2012, p. 51; Michigan Natural Features 
Inventory 2012, p. 4). For example, roads and residential development 
likely disrupted the hydrology of a prairie fen where the Poweshiek 
skipperling was last observed in 2007 and where 2008 and 2009 surveys 
for Poweshiek skipperlings were negative (Michigan Natural Features 
Inventory 2011, unpubl. data). Furthermore, on some sites, land 
managers intentionally facilitated succession of native-prairie 
communities to woody vegetation or trees, such as Ponderosa pine (Pinus 
ponderosa) or spruce (e.g., Dana 1997, p. 5). This converts prairie to 
shrubland, forest, or semi-forested habitat types and facilitates 
invasion of adjacent native prairie by exotic, cool-season grasses, 
such as smooth brome. Moreover, the trees and shrubs provide perches 
for birds that may prey on the butterflies (Royer and Marrone 1992b, p. 
15; 1992a, p. 25).
    We rated the level of impact to populations of invasive species at 
65 Dakota skipper sites and 46 Poweshiek skipperling sites that had 
sufficient information to evaluate the stressor (Table 3 and Table 4; 
Service 2012 unpubl. data; Service 2014, unpubl. data). This stressor 
is considered to have a low level of impact to the populations if there 
was either no information to indicate a stressor or management was 
ongoing to control invasive species using methods that are unlikely to 
cause adverse effects to Dakota skippers or Poweshiek skipperlings 
(e.g., spot-spraying or hand-pulling). Sites were assigned a moderate 
level of impact to populations if invasive species are typically a 
primary driver of management actions and make it difficult for managers 
to specifically tailor management to conserve Dakota skipper or 
Poweshiek skipperling habitat. The site was assigned a high level of 
impact to populations if one or more nonnative invasive plant species 
are abundant or increasing and management activities are not being 
implemented to control their expansion; or if necessary management 
actions cannot be implemented without themselves causing an additional 
stressor to the Dakota skipper or Poweshiek skipperling populations at 
the site.
    Invasive species are a current and ongoing stressor with high 
levels of impact to Dakota skipper and Poweshiek skipperling 
populations on sites where land management is conducive to their 
invasion or expansion or where they have become so pervasive that even 
favorable management may not be quickly effective. Succession is a 
current and ongoing stressor of moderate-level impact to populations at 
sites where management is insufficient. The stressor of invasive 
species to populations on small and isolated sites (e.g., Big Stone 
NWR) is a current and ongoing stressor of high level of impact to 
populations, because Dakota skipper and Poweshiek skipperling 
populations have little resilience to the resulting habitat degradation 
and to the often aggressive management needed to control the invasive 
plants. Loss of habitat or degradation of the native plant community 
due to encroachment of invasive species or woody vegetation is 
considered a high level of impact to populations at 12 of the 65 
assessed Dakota skipper sites, a moderate level of impact to 
populations at 33 sites, and low impact to populations at 20 sites. 
Sites with high and moderate level of impact occur throughout the 
species range in Minnesota, and North and South Dakota (Service 2012 
unpubl. data; Service 2014, unpubl. data). Similarly, invasive species 
are a stressor of high level of impact to populations at 6 of the 46 
evaluated Poweshiek skipperling sites, moderate level of impact to 
populations at 29 sites, and low level of impact to populations at 11 
sites--sites with high and moderate levels of impact are throughout the 
range of the species in Iowa, Minnesota, Michigan, North Dakota, South 
Dakota, Wisconsin, and Manitoba and include at least 9 of the 12 sites 
where the species is still present (Service 2014, unpubl. data).

Fire

    Dakota skipper and Poweshiek skipperling populations existed 
historically in a vast ecosystem maintained in part by fire. Due to the 
great extent of tallgrass prairie in the past, fire and other intense 
disturbances (e.g., locally intensive bison grazing) likely affected 
only a small proportion of the habitat each year, allowing for 
recolonization from unaffected areas during the subsequent flight 
period (Swengel 1998, p. 83). Fire can improve Poweshiek skipperling 
(Cuthrell 2009, pers. comm.) and Dakota skipper habitat (e.g., by 
helping to control woody vegetation encroachment), but it may also kill 
most or all of the individuals in the burned units and alter entire 
remnant prairie patches, if not properly managed (e.g., depends on the 
timing, intensity, etc.). Accidental wildfires also may burn entire 
prairie tracts (Dana 1997, p. 15) and may hamper plans to carefully 
manage Dakota skipper and Poweshiek skipperling habitat. A human-set 
wildfire in late fall 2009 and another extensive fire in 2011, for 
example, burned considerable amounts of good prairie habitat in The 
Nature Conservancy of Canada's Tall Grass

[[Page 63723]]

Prairie Preserve in Manitoba (Hamel et al. 2013, p. 1; Westwood 2010, 
pers. comm.), which is the only location in Canada where Poweshiek 
skipperlings are present; Dakota skippers are extirpated from the site. 
The fires at The Nature Conservancy of Canada's Tall Grass Prairie 
Preserve may have killed overwintering larvae, and the population of 
Poweshiek skipperling in Canada ``may have been greatly reduced as a 
result of these fires'' (Hamel et al. 2013, p. 1).
    Intentional fires, without careful planning, may also have 
significant adverse effects on populations of Dakota skippers and 
Poweshiek skipperlings, especially after repeated events (McCabe 1981, 
pp. 190-191; Dana 1991, pp. 41-45, 54-55; Swengel 1998, p. 83; Orwig 
and Schlicht 1999, pp. 6, 8). In systematic surveys of Minnesota 
tallgrass prairies, for example, Dakota skippers were less abundant on 
sites that had been burned, compared with otherwise similar hayed sites 
(Swengel 1998, p. 80; Swengel and Swengel 1999, pp. 278-279). 
Similarly, Schlicht (1997b, p. 5) counted fewer Dakota skippers per 
hour in burned than on grazed sites in Minnesota. Orwig and Schlicht 
(1999, p. 8) speculated that inappropriate use of prescribed burning 
eliminated Dakota skippers from the last known occupied site in Iowa, a 
65-ha (160-ac) preserve. The effects of fire on prairie butterfly 
populations are difficult to ascertain (Dana 2008, p. 18), but the 
apparent hypersensitivity of Poweshiek skipperlings and Dakota skippers 
indicates that it is a stressor to both species in habitats burned too 
frequently or too broadly. The Poweshiek skipperling and Dakota skipper 
are not known to disperse widely (Swengel 1996, p. 81; Burke et al. 
2011, p. 2279); therefore, in order to reap the benefits of fire to 
habitat quality, Poweshiek skipperlings and Dakota skippers must either 
survive in numbers sufficient to rebuild populations after the fire or 
recolonize the area from a nearby unburned area. In addition, the 
return interval of fires needs to be infrequent enough to allow for 
recovery of the populations between burns. Therefore, fire is a 
stressor to Poweshiek skipperlings and Dakota skippers at any site 
where too little of the species' habitat is left unburned or where 
patches are burned too frequently.
    Panzer (2002, p. 1306) identified four life-history traits of duff-
dwelling insects (such as the Dakota skipper and Poweshiek skipperling) 
that were good predictors of a negative response to fire: (1) Remnant 
dependence (occurring as small, isolated populations); (2) upland 
inhabitance (dry uplands burn more thoroughly than wetter habitats); 
(3) nonvagility (low recolonization rate); and (4) univoltine (slower 
recovery rates for species with only one generation per year). Species 
exhibiting all four traits should be considered ``hypersensitive'' to 
fire (Panzer 2002, p. 1306). While not specifically included in his 
study, the Poweshiek skipperling and Dakota skipper meet all of 
Panzer's criteria for hypersensitivity (Panzer 2002, p. 1306) and have 
additional life-history traits that further suggest hypersensitivity to 
fire. Panzer (2002) observed mean declines of 67 percent among fire-
negative species, although actual mortality was likely higher due to 
some immigration into experimental areas after the burn. When all or 
large portions of prairie remnants are burned, many or all prairie 
butterflies may be eliminated at once. Complete extirpation of a 
population, however, may not occur after a single burn event (Panzer 
2002, p. 1306), and the extent of effects would vary depending on time 
of year and fuel load.
    Poweshiek skipperlings lay their eggs near the tips of leaf blades, 
and they overwinter as larvae on the host plants (Borkin 2000, p. 2), 
where they are exposed to fires during their larval stages. Poweshiek 
skipperlings have also been documented laying eggs on the entire length 
of grass leaf blades and on low-growing deciduous foliage (Dupont 2013, 
p. 133). If larvae are on prairie dropseed or little bluestem, which 
occur in dry prairie, rather than spike-rush or sedges, which typically 
occur in wet prairie, then the larvae are even more vulnerable to fire 
(Selby 2005, p. 36). Unlike Dakota skippers, Poweshiek skipperlings do 
not burrow into the soil surface (McAlpine 1972, pp. 88-92; Borkin 
1995, p. 9), which makes them more vulnerable to fire (and likely more 
vulnerable to chemicals such as herbicides and pesticides) throughout 
their larval stages. Species whose larvae spend more time above ground, 
such as Poweshiek skipperlings, are likely more vulnerable to fire than 
species that form underground shelters. As the spring progresses, 
however, the vulnerability of Dakota skippers to fire increases as 
larvae shift from buried shelters to horizontal shelters at the soil 
surface (Dana 1991, p. 16).
    Studies of all life-stages may be necessary to fully evaluate these 
species' response to fire. Early spring burns may be less likely to 
harm Dakota skipper populations than late spring burns, due to larval 
phenology and differences in subsurface soil temperatures during the 
fire; however, studies have not conclusively linked the relationship of 
mortality risk to the timing of spring burns. Experiments to evaluate 
the effects of early spring versus late spring fires and of different 
fuel levels on Dakota skipper mortality found that, despite higher 
ambient temperatures during the early spring burn, temperatures at the 
average depth of buried Dakota skipper shelters (Dana 1991, p. 11) were 
10 [deg]C (50 [deg]F) higher during the late-spring burn (Dana 1991, p. 
41). Fuel load was positively related to subsurface soil temperature 
(Dana 1991, pp. 41-43). Fuel loads that were clearly associated with 
lethal subsoil temperatures, however, were more typical of mesic 
tallgrass prairie, which had about twice the fuel loads of the dry-
mesic habitats inhabited by Dakota skippers on the site (Dana 1991, pp. 
41, 54). Although Dana's study was inconclusive in quantifying the risk 
of mortality in relation to the timing of spring burns, he was able to 
conclude that a late-spring burn in ``moderate'' fuels (430-440 g/m\2\) 
would have a devastating effect on Dakota skipper populations, and that 
early spring burning would afford some amelioration (Dana 1991, p. 55).
    Rotational burning may benefit prairie butterflies by increasing 
nectar plant density and by positively affecting soil temperature and 
near-surface humidity levels due to reductions in litter (Dana 1991, 
pp. 53-55; Murphy et al. 2005, p. 208; Dana 2008, p. 20). Purple 
coneflower and little bluestem, for example, occurred more frequently 
on burned areas than on unburned areas in mixed-grass prairie at 
Lostwood National Wildlife Refuge in northwestern North Dakota (Murphy 
et al. 2005, pp. 208-209). An increase in purple coneflower, an 
important nectar source for Dakota skippers and Poweshiek skipperlings, 
may last for 1-2 years after early spring fires, and females may 
preferentially oviposit near concentrations of this nectar source (Dana 
2008, p. 20).
    Although fire tends to increase native plant diversity in prairies 
(Murphy et al. 2005, pp. 208-209), several years may be necessary for 
Dakota skipper and Poweshiek skipperling populations to recover after a 
burn. Few studies have documented recovery times for prairie 
butterflies after a burn, and even fewer have measured the 
relationships between species abundance in tallgrass prairies and time 
since burn. One such study, however, found lower relative abundances of 
Dakota skippers and Poweshiek skipperlings in burned units than in 
otherwise similar hayed units even 4 years after burns (Swengel 1996, 
p. 83). Poweshiek skipperling had the most negative initial response to 
fire

[[Page 63724]]

among six species of prairie-obligate butterfly species (Swengel 1996, 
p. 83). Numbers were still lower than expected 1 year post-fire, 
exceeded expectations after 2 years, and declined slightly after 3 
years (Swengel 1996, p. 83). In habitats that had not been burned for 4 
or more years, Poweshiek skipperling abundance was about as low as in 
habitats sampled less than 1 year after being burned (Swengel 1996, p. 
83). The 2012 spring burn that comprised approximately 25-30 percent of 
the breeding habitat at Scuppernong SNA may have contributed to the 
apparent absence of the species in 2013--the relatively small 
population that was also affected by the 2012 summer drought and the 
cold wet spring of 2013 (Borkin 2014, pers. comm.)
    Poweshiek skipperling numbers decline in burned areas for at least 
1-2 years after the burn, and may take several years to rebound, but 
may decline again if management does not maintain the habitat (Skadsen 
2001, p. 37; Webster 2003, p. 12). In general, rebound times of 1-5 
years postburn have been predicted (Panzer 2002, pp. 1302-1303); 
however, Vogel et. al (2010, p. 671) found that habitat-specialist 
butterfly abundance rebound time was approximately 50 months after 
prescribed fires. Swengel (1996, pp. 73, 78-79) describes that the 
negative effects of fire persist for prairie specialists for 3 to 5 
plus years, and these species were collectively the most abundant after 
5 or more years since the last fire. In Manitoba, Poweshiek skipperling 
populations were most numerous in sites burned 5-8 years previously--
the species was absent in sites that were burned the previous year, in 
small numbers in areas that were burned 2-4 years prior, and absent 
from areas that were burned 10 or more years previous to the survey 
(Dupont 2013, pp. 4, 86-87). Recent survey results in some areas, most 
notably, Iowa and Minnesota, indicate that other factors are acting 
independently (Dana 2008, p. 18) or in concert with fire to forestall 
post-fire rebound.
    We assessed the stressor posed by fire at 20 Dakota skipper sites 
with present or unknown status and 16 Poweshiek skipperling sites with 
present or unknown status where we had sufficient information to 
evaluate the stressor (Tables 3 and 4; Service 2012, unpubl. data; 
Service 2014, unpubl. data). We considered fire a stressor of high 
level of impact to populations at 10 of the 20 evaluated Dakota skipper 
sites and 4 of the 16 Poweshiek skipperling sites. Sites that face a 
high level of impact to populations were primarily those with a high 
proportion of Dakota skipper or Poweshiek skipperling habitat that may 
be burned in a single year or where all of the species' habitat is 
burned with no likely source of immigrants to sustain the population. 
This type of fire management is a documented cause of extirpation 
(Selby 2000, p. 19). Sites with a moderate level of impact to 
populations from fire management were those where the habitat is 
divided into at least three burn units and no unit is burned more 
frequently than once every 3 years; or, habitat is divided into two or 
more burn units, each unit is burned no more frequently than once every 
3 years, but the entirety of the species' habitat is never burned in 
the same year and the species is present at another site that is less 
than 1 km (1.6 mi) away.
    Fire is considered to be a stressor of moderate severity at 4 of 
the 20 evaluated Dakota skipper sites and 2 of the 16 Poweshiek 
skipperling sites. Fire presents a low level of impact to populations 
at sites where the species' habitat is divided into at least four burn 
units and no unit is burned more frequently than once every 4 years; 
or, the species' habitat is divided into three or more burn units, at 
least three units are burned no more frequently than once every 4 
years, and the site contains more than 140 ha (346 ac) of native 
prairie or where the site is separated from another occupied site by 
less than 1 km (1.6 mi). Fire is considered to be a stressor with a low 
level of impact to populations at 6 of the 20 evaluated Dakota skipper 
sites and 10 of the 16 Poweshiek skipperling sites.
    In summary, fire may be an important management tool for these 
butterflies, if carried out appropriately. However, where managers burn 
without ensuring a sufficient amount of contiguous or nearby habitat 
from which immigrants can re-inhabit burned areas or if not conducted 
with conservation of prairie invertebrates as a primary objective, fire 
is a current stressor that can have moderate impacts on populations. 
Uncontrolled wildfires may also have high or moderate levels of impacts 
to populations, and would also depend on the timing, intensity, and 
extent of the burn. Poweshiek skipperlings may be among the most 
sensitive of prairie butterflies to fire, and thus, coordination 
between habitat managers and butterfly experts is necessary to ensure 
that it is not implemented in a manner that degrades population 
viability. Fire is a current and ongoing stressor of high level of 
impact where burns occur without ensuring there is a sufficient amount 
of contiguous or nearby habitat from which immigrants can re-inhabit 
burned areas. Fire is an ongoing stressor rangewide for both species 
and has been documented at a high or moderate level of impact to 
populations at several sites in North Dakota, South Dakota, Minnesota, 
Wisconsin, and the Tallgrass Prairie Preserve in Manitoba.

Grazing

    As with fire management, grazing may maintain habitat for the 
Poweshiek skipperling and Dakota skipper, but as with any management 
practice, appropriate timing, frequency, and intensity are important. 
The level of impact of grazing on Dakota skipper and Poweshiek 
skipperling populations also depends on the type of habitat that is 
being grazed. In contrast to the permanent habitat destruction and 
larval mortality caused by plowing or mining, for example, some 
habitats can remain suitable for the Dakota skipper and Poweshiek 
skipperling when grazed (Dana 1991, p. 54, Schlicht 1997, p. 5, Skadsen 
1997, pp. 24-29), and native plant diversity in tallgrass prairie may 
recover from overgrazing if it has not been too severe or prolonged. In 
addition, grazing may be a valuable tool for controlling smooth brome 
invasion and maintaining native diversity in prairies, especially where 
circumstances make the use of fire difficult or undesirable (Service 
2006, p. 2; Smart et al. 2013, pp. 685-686). Conversely, grazing may 
stimulate brome growth and reduce native plant diversity.
    Grazing may benefit the Dakota skipper and Poweshiek skipperling 
under some management scenarios (e.g., adaptive management to adjust 
grazing prescriptions according to their effects on essential features 
of the prairie ecosystem). In some habitats, Dakota skippers benefit 
from light grazing that minimizes the area dominated by tall grasses 
(e.g., big bluestem and indiangrass) (Dana 1991, p. 54). Dakota 
skippers were relatively abundant on prairies subjected to light 
grazing regimes, but absent on nearby idle prairies that were no longer 
used for grazing; moreover, more Dakota skippers were observed per hour 
on the lightly grazed prairies than on nearby habitat managed with fire 
(Schlicht 1997b, p. 5). Similarly, in eastern South Dakota, Dakota 
skipper populations were deemed secure at some sites managed with 
rotational grazing light enough to maintain plant species diversity 
(Skadsen 1997, pp. 24-29), but the species was since extirpated at one 
site where a change in ownership resulted in significant overgrazing 
(Skadsen 2006b, p. 5). The economic benefit of grazing to ranchers may 
also benefit the species at some sites by deterring conversion of 
remnant prairies to row crop agriculture; however, recent

[[Page 63725]]

evidence indicates that conversion is more economically viable (Dowd 
2013, pers. comm.).
    Bison (Bison bison) grazed at least some Dakota skipper and 
Poweshiek skipperling habitats historically (McCabe 1981, p. 190; Bragg 
1995, p. 68; Schlicht and Orwig 1998, pp. 4, 8; Trager et al. 2004, pp. 
237-238), but cattle (Bos taurus) are now the principal grazing 
ungulate in both species' ranges. Bison and cattle both feed primarily 
on grass, but have some dissimilar effects on prairie habitats 
(Damhoureyeh and Hartnett 1997, pp. 1721-1725; Matlack et al. 2001, pp. 
366-367). Cattle consume proportionally more grass and grasslike plants 
than bison, whereas bison consume more browse and forbs (flowering 
herbaceous plants) (Damhoureyeh and Hartnett 1997, p. 1719). Grasslands 
grazed by bison may also have greater plant species richness and 
spatial heterogeneity than those grazed by cattle (Towne et al. 2005, 
pp. 1553-1555). Both species remove forage for larvae (palatable grass 
tissue) and adults (nectar-bearing plant parts), change vegetation 
structure, trample larvae, and alter larval microhabitats. Livestock 
grazing was identified as a stressor to populations on most of the 
privately owned sites and some public sites on which Dakota skippers 
occurred in 2002 (Cochrane and Delphey 2002, pp. 62-69). Swengel and 
Swengel (1999, p. 286), for example, noted that at the Sheyenne 
National Grassland in North Dakota, grazing appeared to be unfavorable 
for the Poweshiek skipperling and Dakota skipper.
    Reduced availability of nectar resources and larval food plants is 
likely the primary factor leading to declines in Poweshiek skipperling 
and Dakota skipper populations on heavily grazed sites. In South 
Dakota, for example, Higgins (1999, p. 15) found lower plant diversity 
on privately owned prairies, which were mostly grazed, than on publicly 
owned prairies, which were almost all idle (no grazing or fire 
management). McCabe (1981, p. 189) observed that grazing eliminated 
Dakota skippers on North Dakota wet-mesic prairies; nectar plants such 
as yellow sundrops and bluebell bellflower rapidly diminished with 
light grazing, and heavy grazing eliminated upright prairie coneflower 
and purple coneflower. In Manitoba, certain levels of grazing are 
likely to adversely affect Dakota skipper populations in proportion to 
its intensity because it removes nectar sources (e.g., Rigney 2013a, 
pp. 143 and 153).
    The intensity at which grazing occurs may dictate the level of 
impact to the Dakota skipper and Poweshiek skipperling, and grazing may 
have a larger impact on the Poweshiek skipperling than the Dakota 
skipper (Westwood 2013, pers. comm.). Grazing reduces Dakota skipper 
numbers in direct proportion to its intensity, due to the reduction in 
flowers that provide nectar and perhaps by influencing adult behavior 
(Dana 1997, p. 4). Dana (1997, p. 5) predicted that privately owned 
pastures in Minnesota's Hole-in-the-Mountain complex, for example, will 
likely only support low densities of skippers if they continued to be 
heavily grazed and sprayed with herbicides. Surveys at this habitat 
complex in 2007, 2008, and 2012 failed to record any Poweshiek 
skipperlings (Dana 2008, p. 8; Selby 2009a, pp. xxxi-xxxii; Runquist 
2012a, pers. comm.; Runquist 2012, pp. 13-14, 18-20), and Dakota 
skippers were not detected in 2012 surveys (Runquist 2012, pp. 13-14, 
18-20; Runquist 2012a, pers. comm.).
    While most references to grazing impacts on prairie butterflies are 
based on ancillary observations made during research focused on other 
management impacts, one Minnesota study (Selby 2006b) focused on the 
effects of grazing on all life stages of the Dakota skipper, and also 
included data for the adult stage of the Poweshiek skipperling. Both 
species were too scarce to collect data adequate to test the hypotheses 
(Selby 2006b, p. 2), but observations based on 2 years (2003 and 2004) 
of surveys suggested that numbers in the lightly to moderately grazed 
pasture were similar to those in the best portions of nearby ungrazed 
habitats (Selby 2006b, p. 30). Poweshiek skipperlings were almost 
absent from the study sites (Selby 2006b, pp. iii-xxiii). Within the 
grazed study area, the number of Dakota skippers declined with 
increasing grazing intensity; Dakota skippers were absent from the most 
heavily grazed areas (Selby 2006b, p. 16). Skadsen (2001, p. 55) found 
that native forb diversity was poor on the grazed lands and predicted 
the extirpation of both species unless management practices were 
changed. The Dakota skipper is now extirpated at one of these sites, 
and its status is unknown at the other; Poweshiek skipperling status is 
unknown at both sites (Service 2014, unpubl. geodatabase). Spomer 
(2004, p. 4) found that larval host plants and nectar sources were 
missing from heavily grazed pastures at Sheyenne National Grassland, 
North Dakota.
    Grazing intensity combined with varying habitat type may also 
affect the level of grazing impacts. On wet-mesic habitat in North 
Dakota, for example, Dakota skippers and Poweshiek skipperlings 
tolerate little to no grazing (McCabe and Post 1977, pp. 36-38; Royer 
and Marrone 1992a, pp. 10, 17, 28; Royer and Marrone 1992b, pp. 17-18; 
Royer and Royer 1998, p. 22). Webster (2003, pp. 7-8) described very 
similar Dakota skipper habitats in Manitoba and, although grazing 
generally does not occur in these habitats that are occupied by Dakota 
skipper, they may be as sensitive to grazing as similar habitats in 
North Dakota; in a later report, he described the conversion of lands 
from haying to grazing as a major stressor to Dakota skipper in the 
wet-mesic habitats of Manitoba (Webster 2007, pp. i-ii, 6). More 
recently, it is thought that the effects of grazing in Manitoba and 
Saskatchewan, as stated in Webster (2007, entire), may not be 
applicable under current population sizes, and that even light grazing 
may be detrimental on dry short grass prairie sites prior to and during 
the Dakota skipper flight period (Westwood 2013, pers. comm.).
    In the drier and hillier habitats that the species inhabits, 
grazing may benefit Dakota skipper depending on its intensity. For 
example, in eastern South Dakota, Dakota skipper populations were 
deemed secure at some sites managed with rotational grazing that was 
sufficiently light to maintain native plant species diversity (Skadsen 
1997, pp. 24-29), and grazing may also benefit Dakota skippers by 
reducing the area dominated by tall native grasses, such as big 
bluestem and Indiangrass (Dana 1991). Proximity of nearby populations 
or contiguous habitat may alleviate some of the negative impacts of 
grazing. Royer and Marrone (1992b, p. 29; 1992a, p. 18) stated that 
heavy grazing was a stressor to Dakota skippers and Poweshiek 
skipperlings, but that occasional light grazing is not a long-term 
stressor in some habitats as long as there are areas of contiguous 
habitat that remain ungrazed. At Chekapa Creek Ridge and Knapp Pasture 
in South Dakota, heavy grazing apparently extirpated both the Poweshiek 
skipperling and Dakota skipper (Skadsen 2002, p. 38; 2004, p. 7; 2006a, 
p. 11). Due to its proximity to other Poweshiek skipperling populations 
and a return to fall haying in 2005, the Poweshiek skipperling 
recolonized Chekapa Creek Ridge in 2006 (Skadsen 2006a, p. 12), but 
more recent surveys indicate that the Poweshiek skipperling has again 
been extirpated from this site due to habitat degradation because of a 
change from haying to grazing (Skadsen 2012a, pers. comm., Skadsen 
2012c, pers. comm.).
    As with fire, Dakota skipper and Poweshiek skipperling populations 
may persist through intense grazing episodes

[[Page 63726]]

or be restored afterwards, if sufficient numbers survive and reproduce 
in lightly grazed patches or if nearby habitats provide sufficient 
numbers of immigrants to reestablish the population after habitat 
quality is restored. Years of grazing without rest, however, may 
preclude recovery from the effects of intense grazing, although the 
capacity for restoration of suitable plant community and other habitat 
features may be highly variable among sites. On some sites, plant 
diversity may not be restored when grazing pressure declines (Dana 
1997, p. 30; Jackson 1999, pp. 134-135; Spomer 2004, p. 4). Grazing 
intensely (where a high proportion of plant biomass is removed) or for 
long duration leads to native plants being replaced with exotic, cool-
season European forage grasses and legumes that are tolerant of 
continuous grazing (Jackson 1999, p. 128, Minnesota DNR 2006, p. 232). 
In overgrazed native prairie in Minnesota, for example, the prairie is 
dominated by exotic grasses with a low native forb species diversity 
and abundance, and foliage height is less than 10 cm (4 in) (Dana 1997, 
p. 3); these prairies lack the native plants necessary to sustain adult 
and larval prairie butterflies. In comparison, sites less disturbed by 
grazing have a high native forb (nectar) species diversity and 
abundance foliage height is generally more conducive to perching and 
reproductive activities (between 25 and 40 cm (10 and 16 in)) (Dana 
1997, p. 2).
    Land managers also frequently use herbicides, often through 
broadcast application, to control weeds and brush on grazed remnant 
prairies, which further reduces native forb diversity and abundance 
(Dana 1997, p. 3; Stark et al. 2012, pp. 25, 27) necessary for adult 
nectar sources. Skadsen (2006, p. 11), for example, documented the 
likely extirpation of Dakota skippers at Knapp Ranch in South Dakota 
after a July 2006 application of broadleaf herbicide in concert with 
heavy grazing. Herbicide and pesticide use is discussed further under 
Factor E of this final rule.
    While reduced availability of nectar resources and larval food 
plants may be the primary factors leading to declines in Poweshiek 
skipperling and Dakota skipper populations on heavily grazed sites, 
changes in vegetation structure may also be important. For example, 
grazing prairie each year during mid-summer eliminates nectar plants, 
such as purple coneflower, and native warm-season grasses that function 
as larval host plants (Skadsen 2007, pers. comm.). In South Dakota, 
vegetation height and litter depth were lower on prairie remnants that 
were mostly grazed (Higgins 1999, pp. 27-29). Grazing also causes 
direct mortality of larvae due to trampling and altering larval 
microhabitats (Royer et al. 2008, pp. 10-15). In North Dakota, grazing 
can compact soils in wet-mesic prairie inhabited by Dakota skippers and 
Poweshiek skipperlings, altering vertical water movement in the soil, 
which may lead to larval desiccation (Royer et al. 2008, p. 16) and may 
inhibit subsurface shelter construction, potentially increasing larval 
vulnerability to predators, parasites, and other environmental 
stressors (Dana 2013, pers. comm.). Cattle may also kill larvae by 
trampling them, particularly in wet-mesic prairies (McCabe 1981, p. 
189).
    Livestock grazing is the predominant use of privately owned 
tallgrass prairie remnants in South Dakota (Higgins 1999, p. 15) and 
was identified by the Service as a stressor on most of the privately 
owned sites on which Dakota skipper occurred when the species was 
identified as a candidate species in 2002 (Cochrane and Delphey 2002, 
pp. 62-69). The presence and density of purple coneflower may serve as 
an indicator of grazing impacts to Dakota skippers and Poweshiek 
skipperlings where the species occur in dry-mesic prairie (Skadsen 
2006a, p. 2); grazing from mid-June through July may reduce purple 
coneflower abundance (Skadsen 2007, pers. comm.)--as discussed in the 
Background section of this rule, purple coneflower has been identified 
as a primary source of nectar for both species, particularly in dry 
prairie habitats.
    Britten and Glasford (2002, p. 373) recommended minimizing 
disturbance of Dakota skipper habitat during the flight period (late 
June to early July) to maximize genetically effective population sizes 
(the number of adults reproducing) to offset the effects of genetic 
drift of small populations (change in gene frequency over time due to 
random sampling or chance, rather than natural selection). Therefore, a 
large portion of the habitat of any Dakota skipper population should 
remain ungrazed or only lightly grazed during the flight period, and 
similar precautions should be taken for the Poweshiek skipperling.
    We assessed the level of impact to populations from grazing at 52 
Dakota skipper sites and 16 sites currently occupied by Poweshiek 
skipperling with present or unknown status that had sufficient 
information to evaluate the stressor (Tables 3 and 4; Service 2012 
unpubl. data; Service 2014, unpubl. data). This analysis was conducted 
differently for different habitat types. For Type A habitat (Royer et 
al. 2008, pp. 14-16) where stocking rates (number of cattle or bison 
over a given area) have little or no evidence of grazing effects on 
Dakota skipper or Poweshiek skipper habitat quality, we found the level 
of impact to populations of grazing to be low. For Type B habitat 
(Royer et al. 2008, p. 14), we assumed that the level of impact of 
grazing to populations would be low if the dry-mesic slopes were grazed 
only before June 1 with at least one year of rest between rotations and 
if the pasture were only spot-sprayed with herbicides when and where 
necessary, or, the best available information does not indicate that 
grazing practices are degrading habitat quality for the species (i.e., 
no apparent diminishment of nectar plant density and diversity and 
habitat is good or excellent for Dakota skipper).
    At grazed sites where extirpation of the local population is not 
imminent, but habitat quality is fair to poor and the relative 
abundance of Dakota skippers or Poweshiek skipperlings is often low, we 
found the level of impact of grazing to populations to be moderate. 
Sites with a moderate level of impact to populations due to grazing may 
be lightly grazed for less than 4 months or less than 25 percent of the 
above-ground biomass of native grasses and forbs is consumed (Smart et 
al. 2011, pp. 182-183), are grazed after June 1, or are not given a 
year of rest between grazed years. At sites where grazing is conducted 
season-long, or for more than 4 months during the year, or more than 50 
percent of the above-ground biomass of native grasses and forbs is 
consumed and herbicide use is frequent, we found the level of impact of 
grazing to populations to be high. At sites where grazing is a high-
level stressor, extirpation of the population is likely imminent and 
habitat quality is poor. On public lands inhabited by the species, 
grazing is typically used to control nonnative cool-season grasses and 
invasive species. Cattle are often removed by July 1 to minimize 
adverse impacts to warm-season grasses, but this type of management 
minimizes the density of nectar species that are important to the 
Dakota skipper and Poweshiek skipperling. Invasive species are often 
present at grazed sites, which often leads to further management 
actions (see Invasive Species and Secondary Succession).
    Of the 52 Dakota skipper sites assessed, we found the level of 
impact to Dakota skipper populations from grazing to be high at 9 
sites, moderate at 29 sites, and low at 14 sites (Service 2012 unpubl. 
data; Service 2014, unpubl. data). Moderate- to high-level impacts to 
populations were primarily at South Dakota sites (N=27)--other

[[Page 63727]]

sites with moderate- to high-level impacts were in Minnesota (N=7), 
North Dakota (N=3), and Manitoba (N=1). As described above as part of 
our assessment of grazing, we examined the habitat quality ratings that 
were primarily assigned by researchers during surveys for the species, 
during separate habitat assessments, or that were available from State 
heritage databases or other sources of scientific data. The habitat 
quality was rated as poor at 7 of the 9 sites where grazing poses a 
high level of impact to Dakota skipper populations. At each of the 14 
sites where grazing pressure is low, habitat quality was good or 
excellent, with two exceptions where habitat was rated as fair to good. 
Among the 29 sites where grazing is a moderate level of impact to 
Dakota skipper populations, 6 had habitat rated good or excellent.
    Of the 16 Poweshiek skipperling sites for which we had sufficient 
information to assess grazing, the level of impact to populations from 
grazing is high at 4 sites, moderate at 10 sites, and low at 2 sites--
all but 2 of these sites were in South Dakota. No sites in Wisconsin or 
Michigan were assessed for grazing impacts to populations, where the 
grazing does not occur. Among the 10 sites where grazing is a moderate 
level of impact to Poweshiek skipperling populations, 8 have habitat 
rated as fair to excellent. The habitat quality was rated as poor at 2 
of the 4 sites where grazing is having a high level of impact to 
Poweshiek skipperling populations.
    In summary, grazing may benefit Dakota skippers and Poweshiek 
skipperlings in native tallgrass prairie by increasing native plant 
diversity and patchiness of fires (Minnesota DNR 2006, p. 232). The 
economic benefit of grazing to ranchers may also be a benefit to the 
species by deterring conversion of remnant prairies to row crop 
agriculture. Grazing is a stressor to these species, however, if it is 
not managed with the goal of conserving native-prairie vegetation that 
comprises suitable habitat for Dakota skipper and Poweshiek 
skipperling. Dakota skippers and Poweshiek skipperlings may benefit 
when prairie habitat is rested from grazing for at least a part of each 
growing season, if livestock are precluded from removing too much plant 
material (e.g., are moved when stubble heights are 6-8 in (15-20 cm) 
(Skadsen 2007, pers. comm.), and if the timing of grazing for each 
field varies from year to year (Skadsen 2007, pers. comm.). Grazing 
management recommendations may not be universally applicable to all 
locations, and may depend on the habitat type and other ecological and 
physical conditions of the site. For instance, stubble heights of 6-8 
inches may be difficult to attain in certain dry-mesic sites (ND NRCS 
2013, pers. comm.).
    Conversely, Dakota skipper and Poweshiek skipperling populations 
may be reduced or extirpated when too much plant material is removed, 
when fields are not rested for some portion of the growing season, or 
fields are grazed during the same period each year. Grazing poses a 
current and ongoing stressor of moderate to high level of impact to 
populations where its intensity is such that Dakota skippers and 
Poweshiek skipperlings are unlikely to thrive or even persist. Grazing 
poses a likely future stressor where current management is conducive to 
Dakota skipper or Poweshiek skipperling conservation, but where 
landowners may allow excessive grazing in the future, for example, 
where management may change as a result of the changing market prices 
of agricultural products. Unsuitable grazing is an ongoing stressor 
throughout much of the range of the Dakota skipper and Poweshiek 
skipperling (primarily in flat wet prairies of Minnesota, North Dakota, 
and South Dakota); grazing is not a documented stressor at the 
Poweshiek skipperling sites with present or unknown status in 
Wisconsin, Michigan, and Iowa or at most Dakota skipper sites in 
Canada.

Haying

    As with grazing and fire, haying (mowing grasslands and removing 
the cuttings) may maintain habitat for the Poweshiek skipperling and 
Dakota skipper, but as with any management practice, appropriate 
timing, frequency, and intensity are important. Poweshiek skipperling 
habitat at Scuppernong Prairie in Wisconsin, for example, would have 
succeeded to shrubby or forested habitat if it had not been hayed each 
fall (Borkin 2011, in litt.)--it is now one of the few sites in 
Wisconsin that is occupied by the Poweshiek skipperling. Nearly all of 
the Dakota skipper sites in Canada where the species is present are 
privately owned, fall-hayed prairies (Westwood 2013, pers. comm.).
    Haying generally maintains prairie vegetation structure, but it may 
favor expansion of invasive species such as Kentucky bluegrass. If done 
during the adult flight period, haying may kill the adult butterflies 
or cause them to emigrate, and if done before or during the adult 
flight period, it may reduce nectar availability (McCabe 1979, pp. 19-
20; McCabe 1981, p. 190; Dana 1983, p. 33; Royer and Marrone 1992a, p. 
28; Royer and Marrone 1992b. p. 14; Swengel 1996, p. 79; Webster 2003, 
p. 10). Royer and Marrone (1992b, p. 14), for example, ascribed the 
loss of a North Dakota Poweshiek skipperling population to June and 
July haying. Several years of July haying may have led to the Poweshiek 
skipperling's extirpation at Wakidmanwin Prairie in South Dakota 
(Skadsen 2006b, p. 13). The Dakota skipper was observed at the 
Wakidmanwin Prairie in 2010 (Skadsen 2010, p. 6); however, it is not 
clear if the management has changed since the observation. Early June 
haying may have eliminated Dakota skippers from at least one site in 
North Dakota (Royer and Royer 2012a, p. 72).
    Hayed prairies are important reservoirs of native-prairie plant 
diversity; however, long-term annual haying negatively impacts prairie 
plant diversity (Jog et al. 2006, pp. 164-165). Jog et al. (2006, pp. 
164-165) recommended diversifying management to include, for example, 
periodic fire and to forego annual haying to increase plant species 
diversity. In a long-term study of a prairie in southeastern Wisconsin, 
a switch from late-season haying to fire management led to increased 
native plant diversity and coverage of warm-season grasses, although 
woody plant species also increased (Rooney and Leach 2010, p, 319)--
this increased plant diversity was likely an expression of plants that 
were already at that location.
    Late-season haying may benefit Dakota skipper populations (McCabe 
1981, p. 190), and Dakota skipper populations might be more common on 
hayed prairies than on idle (not hayed) prairies (Webster 2003, p. 10). 
Swengel and Swengel (1999, p. 279) observed significantly greater 
relative abundance of Dakota skippers on hayed tracts compared with 
either idle or burned tracts in Minnesota, and Skadsen (2004, p. 7) 
documented the extirpation of Dakota skippers from a site after its 
management switched from haying to intensive grazing. Some remnant 
Dakota skipper populations in the eastern Dakotas are found on fall-
hayed prairies (Skadsen 1997, pp. 10-23; Royer and Royer 2012b) as are 
many of the sites in Manitoba (Webster 2003, p. 10). Webster (2003, p. 
8) found ``healthy populations'' of Dakota skippers in Manitoba on 
sites used as hay fields, as described by the absence of standing dead 
grass, low numbers of shrubs, shorter bluestem grasses, and abundant 
and readily observable nectar flowers, as compared to un-hayed sites. 
Scarlet Fawn Prairie in South Dakota, which is hayed in the fall, is 
considered one of the highest quality prairies in that State (Skadsen 
2012, pers. comm.). In the

[[Page 63728]]

Dakotas, late-season (mid-August to October) haying appears to minimize 
impacts to the prairie butterflies, although annual haying may diminish 
the vigor of native, warm-season grasses and reduce forb density in 
north-central North Dakota (wet-mesic) habitats (Lenz 1999, p. 14; 
Skadsen 2009, p. 8). Consistent late-season haying of Poweshiek 
skipperling habitat in South Dakota, appears to have facilitated the 
expansion of green needlegrass (Stipa viridula), a cool-season grass, 
and prevented seed development in warm-season plants (Skadsen 2009, p. 
8).
    We assessed the level of impact of haying to populations at 41 
Dakota skipper sites and 6 Poweshiek skipperling sites with present or 
unknown status where we had sufficient information to assess the 
stressor (Tables 3 and 4; Service 2012 unpubl. data; Service 2014, 
unpubl. data). Haying was considered to be a stressor with a low or no 
negative impact on populations where it is implemented after the flight 
period (after approximately August 1) and when there is no reduction in 
the availability of native plant species. Haying was considered to be a 
stressor with a moderate level of impact on populations, where the 
exact timing or extent of haying was unknown, but there are: (1) One or 
more indications that haying is resulting in a reduction in nectar or 
larval food sources important to the species due to timing or frequency 
of mowing; (2) part of the Dakota skipper or Poweshiek skipperling 
habitat on the site is hayed before August 1, but a substantial 
proportion of habitat is not hayed and not clearly subject to other 
stressors, such as frequent fire or grazing (e.g., Smokey Lake site, 
North Dakota); or (3) where haying occurs before or after August 1, but 
the site is hayed no more frequently than once every 3 years (e.g., Roy 
West Game Production Area, South Dakota).
    We considered haying to be a stressor with a high level of impact 
on populations where the site was hayed prior to August 1 (e.g., Oaks 
Prairie, North Dakota). At 29 of the 41 evaluated Dakota skipper sites, 
current haying practices are conducive (beneficial) to Dakota skipper 
conservation, because it is conducted after August 1 and is not 
reducing native plant species diversity. One or more indications that 
current haying practices are slowly degrading habitat quality for 
Dakota skippers has been documented at 11 of the 41 sites. At several 
sites in North Dakota, for example, Royer and Royer (2012b, pp. 15, 21, 
24, 45) noted a decrease in the diversity and density of forbs at sites 
hayed annually. Haying is a stressor with a high level of impact on 
populations at 1 of the 41 Dakota skipper sites assessed and a stressor 
of moderate-level impacts to the populations at 11 of the 41 Dakota 
skipper sites assessed. Of the 6 Poweshiek skipperling sites evaluated, 
haying was a stressor with moderate-level impacts on populations at 3 
sites and was not considered to have high-level impacts to the 
populations at any of the 6 sites.
    In summary, haying is a current and ongoing stressor of moderate to 
high level of impacts to Dakota skippers and Poweshiek skipperlings at 
the few sites where the site is normally hayed before August and where 
annual haying is reducing availability of larval food and adult nectar 
plants. However, fall haying is beneficial to both species, 
specifically if it is conducted after the flight period (after August 
1), no more than every other year, and there is no indication that 
native plant species diversity is declining due to timing or frequency 
of haying. Haying is a current stressor at a small number of sites for 
both species; these sites occur primarily in North Dakota and South 
Dakota.

Lack of Disturbance

    While inappropriate or excessive grazing, haying, and burning are 
stressors to some Poweshiek skipperling and Dakota skipper populations 
and have led to the extirpation of others, both species are also 
subject to the stress of no management practices being implemented. 
Prairies that lack periodic disturbance become unsuitable for Poweshiek 
skipperlings and Dakota skippers due to expansion of woody plant 
species (secondary succession), litter accumulation, reduced densities 
of adult nectar and larval food plants, or invasion by nonnative plant 
species (e.g., smooth brome) (McCabe 1981, p. 191; Dana 1983, p. 33; 
Dana 1997, p. 5; Higgins et al. 2000, p. 21; Skadsen 2003, p. 52). For 
example, Dakota skipper numbers were reduced at Felton Prairie, 
Minnesota, in tracts that had not been hayed or burned for several 
years (Braker 1985, p. 47). Another study also observed significantly 
lower Dakota skipper abundance on unmanaged or idle sites, compared 
with hayed sites; however, Poweshiek skipperlings were significantly 
denser with idling (Swengel and Swengel 1999, p. 285). Skadsen (1997, 
pp. 10-23; 2003, pp. 8, 35, 42) reported deterioration of several 
unburned and unhayed South Dakota prairies in just a few years due to 
encroachment of woody plants and invasive species and found lower 
species richness of prairie-dependent butterflies and lower floristic 
quality at sites with no disturbance versus sites managed by grazing or 
fall haying (Skadsen 2006a, p. 3). For example, Dakota skippers 
returned to an idle site, Pickerel Lake State Park, after a burn 
conducted in 2007 resulted in a significant increase in forbs, 
particularly purple coneflower (Skadsen 2008, p. 2). In a separate 
study, Higgins et al. (2000, p. 24) found that prairie habitats left 
idle had lower plant diversity and quality than prairies managed with 
fire.
    Populations of Dakota skippers and Poweshiek skipperlings may also 
be at risk at sites where a private landowner is not aware of the 
presence or potential presence of the species, but would conserve the 
land if they were made aware. The land use in some areas in Canada, for 
example, are currently inadvertently used in ways that are favorable to 
the species (for example, fall haying), but the land use may change in 
the future (Westwood 2014, pers. comm.). In the United States, the 
Service has notified private landowners of the presence or potential 
presence of one or both species on their land at most sites with 
present or unknown occupancy and many sites that are considered 
extirpated or possibly extirpated but still may have suitable habitat.
    We assessed the stressor posed by lack of management for 
populations at 17 Dakota skipper sites and 12 Poweshiek skipperling 
sites with present or unknown status where we had sufficient 
information to evaluate the stressor (Tables 3 and 4; Service 2012 
unpubl. data; Service 2014, unpubl. data). Lack of management was 
considered to be a stressor of moderate-level impacts to the population 
where the species' habitat is degraded or likely to become degraded due 
to secondary succession, invasive species, or both, but actions to 
restore habitat quality are planned or ongoing, or where the site is 
idle with no evident plans to initiate management (e.g., fire, grazing, 
haying), and there are signs of ongoing or imminent secondary 
succession. Lack of management was considered to be a stressor with a 
high level of impact to the population where the habitat quality at a 
site is degraded or likely to become degraded due to secondary 
succession or invasive species, and there are no ongoing or planned 
actions to maintain or restore habitat quality. Lack of management was 
considered to be a stressor of low-level impacts to Dakota skipper or 
Poweshiek skipper populations at sites that are managed by grazing, 
haying/mowing, or fire that precludes loss of Dakota skipper or 
Poweshiek skipperling habitat to

[[Page 63729]]

secondary succession and invasive species (e.g., smooth brome).
    Nine of the 17 Dakota skipper sites assessed are under high level 
of impact to population due to lack of management and 5 sites are under 
moderate level of impact to the population. Four of the 12 Poweshiek 
skipperling sites assessed are under high level of impact to the 
population due to lack of management, and 6 sites are under moderate 
level of impact to the population. The Dakota skipper and Poweshiek 
skipperling are unlikely to persist at those sites where the level of 
impact to the population due to lack of management is high. Sites 
currently under stress by lack of management occur throughout the range 
of both species; however, most of the present or unknown sites that 
lack appropriate management are in North Dakota, South Dakota, 
Minnesota, and Michigan. In summary, lack of disturbance is a current 
and ongoing stressor to Dakota skipper and Poweshiek skipperling 
populations where woody vegetation or invasive species expansion will 
reduce native-prairie grasses and flowering forbs.
Summary of Factor A
    We identified a number of stressors to the habitat of the Dakota 
skipper and Poweshiek skipperling that operated in the past, are 
impacting both species now, and will continue to impact the species in 
the future. The decline of both species is the result of the long-
lasting effects of habitat loss, fragmentation, degradation, and 
modification from agriculture, development, invasive species, secondary 
succession, grazing, and haying. Although efforts have been made to 
effectively manage habitat in some areas, the long-term effects of 
large-scale and wide-ranging habitat modification, destruction, and 
curtailment will last into the future. Invasion of the species' habitat 
by exotic species and woody vegetation, overgrazing, long-lasting or 
permanent alterations in water levels or hydrology, and too frequent or 
improperly timed haying remove or significantly reduce the availability 
of plants that provide nectar for adults and food for larvae. Fire and 
flooding cause direct mortality or destroy nectar and food plants if 
the intensity, extent, or timing is not conducive to the species' 
biology.
    Of the 160 Dakota skipper sites we evaluated for one or more 
habitat stressors, at least 131 sites have at least one documented 
stressor with moderate to high levels of impact to populations--these 
sites are found across the current range of the species in Minnesota, 
North Dakota, South Dakota, Manitoba, and Saskatchewan (Service 2012 
unpubl. data; Service 2014, unpubl. data). Fifty-eight sites have 2 or 
more documented stressors of moderate to high levels of impact to 
populations, and 24 sites have 3 or more documented stressors of 
moderate to high level of impact to populations. Sites with three or 
more stressors are found across most of the current range of the 
species; these sites occur in Minnesota, North Dakota, South Dakota, 
and Manitoba (Service 2012 unpubl. data; Service 2014, unpubl. data). 
Furthermore, concurrently acting stressors may have more intense 
effects than any one stressor acting independently. Therefore, based on 
our analysis of the best available information, present and future loss 
and modification of Dakota skipper habitat is a stressor that has 
significant impacts on populations of the species throughout all of its 
range. Habitat-related stressors occur at sites with Dakota skipper 
populations within every State and province of occurrence.
    Similarly, of the 60 Poweshiek skipperling sites with present or 
unknown status that we analyzed for one or more habitat stressors, 46 
of them have at least one stressor at moderate to high levels of impact 
to the population. These sites are found across the current range of 
the species and occur in Iowa, Michigan, Minnesota, North Dakota, South 
Dakota, Wisconsin, and Manitoba (Service 2014, unpubl. data). Twenty-
five sites have 2 or more documented stressors that have moderate to 
high levels of impact to the population. These sites are found across 
the current range of the species and occur in Iowa, Michigan, 
Minnesota, North Dakota, South Dakota, Wisconsin, and Manitoba (Service 
2014, unpubl. data). Eleven of them have at least three documented 
stressors that have moderate to high levels of impact to the 
population. These sites are found across the current range of the 
species and occur in Iowa, Michigan, Minnesota, South Dakota, and 
Manitoba (Service 2014, unpubl. data). Furthermore, concurrently acting 
stressors may have more intense effects than any one stressor acting 
independently. Therefore, based on our analysis of the best available 
information, present and future loss and modification of Poweshiek 
skipperling habitat is a stressor that has significant impacts on the 
species throughout its range.

Conservation Efforts To Reduce Habitat Destruction, Modification, or 
Curtailment of Its Range

    In the past, funding for conservation of rare species was primarily 
directed toward federally listed or candidate species, so while the 
Poweshiek skipperling may have benefited indirectly from conservation 
activities focused on species such as the Dakota skipper and Mitchell's 
satyr (Neonympha mitchellii mitchelli), it has not generally been the 
primary focus of those activities. As a result, survey data and 
incidental life-history observations have been accumulated as a part of 
projects focused on other species, but surveys were not necessarily 
focused on Poweshiek skipperling sites and detailed life-history, 
population, and demographic data have generally not been collected for 
the species. Various conservation activities directed at the Dakota 
skipper also indirectly benefit the Poweshiek skipperling; these 
activities are summarized below.
    Conservation agencies have recognized the need to address the 
status of prairie butterflies for more than 30 years beginning with a 
1980 workshop held to initiate studies of Dakota skippers and other 
prairie butterflies. In June 1995, the U.S. Fish and Wildlife Service 
convened Dakota skipper experts to outline tasks needed to preserve 
enough viable populations to ensure long-term security for the species. 
The group outlined a plan for surveying populations and characterizing 
sites and habitats at priority areas, identifying and recommending 
management needs, monitoring, and outreach and education; however, this 
plan was not drafted or finalized. In 1999, a Dakota skipper recovery 
strategy meeting was held in South Dakota with State, Federal, and 
nongovernmental biologists attending (Skadsen 1999b, entire). In 2011, 
researchers in Canada organized a Poweshiek Skipperling Workshop and 
followup conference call that brought together researchers and managers 
from across the range of the Poweshiek skipperling to provide updates 
on survey data, discuss ongoing activities, and plan future work. The 
workshop resulted in specific conservation action plans for the 
species. The Minnesota Zoo organized a followup conference during March 
2013 to assess progress of the 2011 Poweshiek Skipperling Workshop 
Action Plans, facilitate discussion on the potential effects of 
management activities on prairie butterflies, identify needed 
information and data gaps, establish new priorities for research and a 
draft

[[Page 63730]]

action plan for 2013, and facilitate networking and collaborations 
focused on the conservation of the Dakota skipper and Poweshiek 
skipperling, as well as other tallgrass prairie butterflies in the 
Midwest--the Northern Tallgrass Prairie Lepidoptera Conservation 
Conference Working Group Report Synthesis is posted at http://www.mnzoo.org/PrairieLepidopteraConference/Northern%20Tallgrass%20Prairie%20Lepidoptera%20Conservation%20Conference%20Working%20Group%20Reports%20-%20Synthesis.pdf.
    Research and survey work has occurred throughout the range of both 
species to document populations, to study the life history of both 
species, and to examine the effects of various management practices, 
such as fire and grazing, on the species and their habitat. For 
example, research and survey work on Dakota skippers began with Dana's 
(1991, entire) doctoral study on fire effects at Hole-in-the-Mountain, 
Minnesota, beginning in 1978 and McCabe's (1981, entire) 1979 surveys 
for the Garrison Diversion project in North Dakota. Additional work has 
been completed on characterizing habitat at important Dakota skipper 
sites in Minnesota (Dana 1997, entire) and North Dakota (Lenz 1999, 
entire, Royer and Royer 1998, entire, Royer and Royer 2012a, entire). 
Royer (2008, entire) assessed abiotic habitat parameters of soil in 
relation to management and conservation of Dakota skippers to 
complement prior floristic characterization of these habitats. The 
Minnesota DNR and the Service planned to cooperatively study the 
effects of grazing on the Dakota skipper and Poweshiek skipperling 
(Selby 2003, entire; Selby 2006b, entire); however, skipper numbers 
were too low to collect sufficient data to test hypotheses (Selby 
2006b, p. 30).
    In the past, the Service funded some management activities intended 
to benefit the Dakota skipper, including habitat management at Big 
Stone National Wildlife Refuge, Minnesota (Olson 2000, entire), 
landowner contacts and education on conservation practices in South 
Dakota (Skadsen 1999b, entire), and prairie vegetation restoration at 
Chippewa Prairie in 2000 and at Twin Valley Prairie SNA, Minnesota, in 
2001. The results of these efforts are varied; for instance, the 
prairie habitat at Twin Valley Prairie SNA was recently rated as 
excellent quality (Service 2014, unpubl. geodatabase), but the status 
of both species at that site is unknown; the last positive observation 
of Dakota skippers and Poweshiek skipperlings was 1993 and 1994, 
respectively. The Dakota skipper is extirpated from Chippewa Prairie, 
and the status of the Poweshiek skipperling is unknown at the site; the 
last positive observations of the species were in 1995 and 1994, 
respectively (Service 2014, unpubl. geodatabase).
    The Service purchases easements to prevent prairie conversion for 
agriculture and provide cost-share to support rotational grazing and 
other practices that may benefit Dakota skippers and Poweshiek 
skipperlings. For example, in 12 counties in South Dakota within the 
range of the species, the Service's grassland easement program has 
protected 365,193 ac (147,788 ha) of grassland that are primarily 
native prairie (Larson 2013, pers. comm.; HAPET 2012, unpubl. data), 
although it is not clear whether these lands are suitable habitat for 
either species. Other Service fee title lands, State lands, and Natural 
Resources Conservation Service (NRCS) easement lands may also protect 
areas from conversion, depending on the protections in those areas 
(Larson 2013, pers. comm.). If easements are near prairie butterfly 
habitat they can minimize the impacts of conversion and may provide 
dispersal corridors or buffer sites from external stressors (e.g., 
pesticide drift).
    Prairie easements generally prevent grasslands from being plowed or 
destroyed and prevent haying before July 16, but may not restrict 
grazing, pesticide use, or other practices that can degrade the status 
of Dakota skipper or Poweshiek skipperling populations. For example, 
one property with a Service easement was recently overgrazed to the 
extent that Dakota skipper was extirpated from the site (Skadsen 2006b, 
p. 5). Cost-share partnerships on easements and other areas, however, 
may further enable landowners to manage grasslands to benefit Dakota 
skippers and other prairie endemic species. The Service may implement 
such actions through the Partners for Fish and Wildlife program or in 
collaboration with NRCS or other agencies. Since 1990, the Service has 
purchased easements to prevent grassland conversion on millions of 
acres in Minnesota, North Dakota, and South Dakota (HAPET 2012, unpubl. 
data). Only some of these areas include Dakota skipper or Poweshiek 
skipperling sites, are within the range of either species, or include 
suitable habitat for either species.
    Conservation-interested agencies, individuals, and Tribes in South 
Dakota have made concerted efforts for decades to conserve native 
prairie within the Dakota skipper range. For example, there are 
approximately 54,000 ac (21,853 ha) of fee title lands in grassland 
that are managed by the Service in 12 of the counties within the 
historical or current range of the Dakota skipper and 365,000 ac 
(147,710 ha) protected by the Services' grassland easement program 
(HAPET 2012, unpubl. data; Larson 2013, pers. comm.). These acreages do 
not include an additional 4,000 ac (1,619 ha) of grass protected by 
acquisitions that have occurred in 2012 (HAPET 2012, unpubl. data; 
Larson 2013, pers. comm.). Not all of these lands, however, may be 
managed in such a manner that is conducive to Dakota skipper 
populations.
    About one-half of the present or unknown Dakota skipper sites 
(total number of present/unknown sites is 171) in the United States are 
privately owned (excluding populations on land owned by The Nature 
Conservancy). Twelve of these populations are on private land on which 
the Service has purchased conservation easements that preclude plowing 
and haying before July 16. Manitoba Habitat Heritage Corporation has an 
easement that overlaps with one Dakota skipper site in Canada (Friesen 
2013, pers. comm.). Similarly, of the 70 privately owned sites where 
Poweshiek skipperling has been recorded since 1985, 8 sites (all in 
Minnesota) have conservation easements. These easements do not 
prescribe grazing practices but are intended to prevent grassland 
conversion to cropland, which is detrimental to Dakota skippers or 
Poweshiek skipperlings. Additional measures on some easement properties 
could ensure grazing practices do not inadvertently impact either 
species.
    The Nature Conservancy's Minnesota and Dakotas offices initiated a 
Prairie Coteau Coordinated Conservation Planning Effort and Plan in 
1998 to facilitate conservation actions by various landowners, 
including private, county, state, tribal and Federal, on high 
biodiversity prairie sites (Skadsen 1999b, entire). Additional partners 
include conservation organizations, local conservation districts, and 
universities. The Nature Conservancy acquired a reserve in the Sheyenne 
Grassland area, Brown Ranch, which is a Dakota skipper site with an 
unknown status, and manages some of the most significant habitats for 
the two species in Minnesota, including the Hole-in-the-Mountain 
Prairie preserve. Based on intensive surveys in 2007, Dana (2008, p. 
19) found ``considerable reassurance'' that the rotational burning 
approach used at Prairie Coteau SNA and Hole-in-the-Mountain Preserve 
is compatible with long-term persistence of the Dakota

[[Page 63731]]

skipper, for example, by controlling woody vegetation encroachment. The 
Minnesota DNR also manages the Prairie Coteau SNA with rotational 
burning (Dana 2008, p. 19), which may control woody vegetation 
encroachment. The Clay County Stewardship Plan (Felton Prairie 
Stewardship Committee 2002) may have reduced the likelihood and 
severity of gravel mining within the Felton Prairie complex in 
Minnesota.
    Many of the best sites for Dakota skipper and Poweshiek skipperling 
in South Dakota are on tribal lands managed by the Sisseton-Wahpeton 
Sioux Tribe (e.g., Scarlet Fawn and Oak Island Prairies) (Skadsen 1997, 
Skadsen 2012b, p. 3), with late-season haying. According to Skadsen 
(2012, p. 3) ``. . . as in prior years, the fall hayed prairies held in 
trust by the Sisseton Wahpeton Oyate had the most diverse native flora 
and thus the largest numbers of Dakota skippers.'' Although these lands 
generally contain high-quality habitat for prairie butterflies in 
eastern South Dakota (Skadsen 2012b, p. 3), a change to alternate year 
haying--instead of annual haying--may further improve habitat quality 
by ensuring that plants that flower during the Dakota skipper and 
Poweshiek skipperling flight periods are able to produce seed (Royer 
and Royer 2012b, p. 15).
    The Day County Conservation District, South Dakota, places a high 
priority on implementing prescribed grazing on rangelands known to 
support Dakota skippers and bordering sites in the Upper Waubay Basin 
Watershed (Skadsen 1999b, p. 3). Their efforts include soliciting 
grants and providing education on grazing management, controlled 
burning, and integrated pest management to control leafy spurge, 
through workshops and a demonstration site. There are five Poweshiek 
skipperling sites in Day County with unknown occupancy and no sites 
where the species is considered to be present. There are a total of 24 
Dakota skipper sites in Day County: 3 sites where the species is 
considered to be present, 11 sites that have an unknown occupancy, and 
the remaining are extirpated or possibly extirpated. It is not known 
how many of these sites are benefiting from these efforts and to what 
degree.
    In South Dakota, completed management plans guide habitat 
restoration at Hartford Beach State Park and Pickerel Lake State 
Recreation Area (Skadsen 2008, pp. 4-7; Skadsen 2011, pp. 1-4). At each 
site, the lack of haying, grazing, or fire had allowed plant succession 
to degrade and reduce the extent of Dakota skipper habitat. Dakota 
skipper habitat at these sites is divided into 3-4 management units. A 
controlled burn was conducted in one unit at Hartford Beach State Park 
in 2008, and shrubs were removed from two of the units (Skadsen 2008, 
p. 4). At Pickerel Lake State Recreation Area, a controlled burn was 
conducted in 2007, and in 2008 the site was hayed and shrubs were 
removed. The Dakota skipper was present in the burned unit for the 
first time since 2002 after ``a dramatic increase in forbs, especially 
purple coneflower, occurred after the burn'' and ``apparently attracted 
Dakota skippers from a nearby site'' (Skadsen 2008, p. 2). The 
Poweshiek skipperling is extirpated from both sites, but the reasons 
for its disappearance are not known (Service 2012, unpubl. data). At 
each site, prescribed fire and brush control are implemented on a 
rotational basis (Skadsen 2011, pp. 1-4); at Pickerel Lake State 
Recreation Area, forbs were planted in 2011 to diversify nectar 
resources for prairie butterflies (Skadsen 2011, pp. 2-4).
    A privately owned ranch with Dakota skippers in Day County, South 
Dakota, is managed with a patch-burn grazing system in which each 
grazing unit is rested for a full year (Skadsen 2008, p. 10), which may 
be beneficial to the species. The effects of patch-burn grazing at this 
site are being studied jointly by The Nature Conservancy and South 
Dakota State University (Skadsen 2008, p. 10).
    In 2005, the Service's National Wildlife Refuge System in North 
Dakota and South Dakota adopted the Conservation Strategy and 
Guidelines for Dakota Skippers on Service Lands in the Dakotas, which 
are based on the Service's Dakota Skipper Conservation Strategy and 
Guidelines and on versions of the Service's conservation guidelines for 
Dakota skipper. The guidelines were revised in March 2013 (http://www.fws.gov/midwest/endangered/insects/dask/DASKconservationguidelines2013.html). In the Dakotas, the Service plans 
to implement the conservation guidelines on all of its lands where the 
Dakota skipper is known to occur--the Service owns 12 Dakota skipper 
sites in the Dakotas where the species is considered present or has 
unknown occupancy. The guidelines also suggest that the Service examine 
other lands under its ownership to determine whether unrecorded 
populations of Dakota skippers may be present and to conduct surveys in 
those areas or manage the site in accordance with the Dakota Skipper 
Conservation Strategy and Guidelines. These guidelines will be reviewed 
and updated to reflect new information as it is developed.
    In Manitoba, August 1st is the recommended earliest haying and 
grazing date at Dakota skipper sites. The recommended intensity of 
grazing is to be as low as economically feasible to prevent permanent 
damage to sites (e.g., destruction of nectar plants). In Manitoba, it 
is recommended that sites that have burned or have been impacted by 
other factors such as extensive flooding, should not be grazed for at 
least one year following these events.
Poweshiek Skipperling
    Most of the conservation initiatives discussed above were put in 
place to benefit the Dakota skipper, but may also benefit the Poweshiek 
skipperling. Conservation initiatives are also in place at several 
Poweshiek skipperling sites in Wisconsin and one or two sites in 
Michigan.
    At least two sites occupied by Poweshiek skipperling in Michigan 
are at least partially owned and managed by the Michigan Nature 
Association (MNA); however, the MNA does not specifically manage for 
Poweshiek skipperling conservation. The State of Michigan owns part or 
all of four occupied Poweshiek skipperling sites; however, most of 
those lands are managed as State recreational areas, not for prairie 
butterfly conservation. Landowners at one fen site are participating in 
a Michigan DNR Land Incentive Program, and a portion of another 
occupied site is part of the Burr Memorial Prairie Plant Preserve 
(Michigan Natural Features Inventory 2011, unpubl. data). The Poweshiek 
skipperling may benefit from conservation activities in place for the 
federally endangered Mitchell's satyr at one Michigan site.
    Poweshiek skipperling sites in Wisconsin are owned and managed by 
the Wisconsin DNR, who manage the land to maintain and improve prairie 
habitat. The Wisconsin DNR recently received a Sustain Our Great Lakes 
(SOGL) grant to conduct invasive species management on several SNAs, 
including Puchyan Prairie (Wisconsin DNR 2012, in litt.). The 
Scuppernong Prairie SNA, Wilton Road, and Kettle Moraine Low Prairie 
SNA are managed primarily through fire and invasive species control.
    Furthermore, the Minnesota Zoo recently initiated a propagation 
research program for the Poweshiek skipperling and Dakota skipper to 
develop methods to propagate these and other species in the future. If 
this program is successful, a conservation benefit could be possible if 
the program could facilitate reintroduction and augmentation efforts 
into areas where the species has

[[Page 63732]]

declined or disappeared. Furthermore, this propagation effort may lead 
to increased knowledge of basic biology and life history of both 
species.
    To summarize, the conservation initiatives discussed above may 
ameliorate one or more stressors on populations of Dakota skipper and 
Poweshiek skipperling at a relatively small number of sites. 
Approximately 12 Dakota skipper sites and 8 Poweshiek skipperling sites 
benefit from conservation easements; an additional 12 Dakota skipper 
sites are owned by the Service and may benefit from implementation of 
Dakota skipper conservation guidelines; 2 sites in State parks are 
undergoing prairie restoration and management; approximately 5 
additional Dakota skipper sites and 4 Poweshiek skipperling sites are 
managed to benefit prairie butterflies, such as rotational fire 
management. Since numerous sites have two or more stressors of moderate 
to high-level impacts to one or both species, all stressors are likely 
not completely ameliorated at many sites. Initiatives such as captive 
propagation and studies of the effects of various management techniques 
may be applied broadly and may be beneficial to each species as a 
whole--the timeframe for these benefits to be realized, however, will 
not be immediate.

Factor B. Overutilization for Commercial, Recreational, Scientific, or 
Educational Purposes

    Although its biology could make the Dakota skipper sensitive to 
collection at some locations, the present level of scientific 
collection is minimal and recreational collecting is unlikely (Royer 
and Marrone 1992a, p. 27). Collection is not known to be a stressor for 
the Poweshiek skipperling (Royer and Marrone 1992b, p. 16). Collection 
is not currently a stressor to either species in Canada (COSEWIC 2003, 
p. 18). Scientific Collectors Permits are required in states where both 
species have legal protection, and permission is often required to 
collect specimens on protected areas. Furthermore, these species are 
not collected for commercial purposes; the drab coloration likely makes 
both species less desirable for collectors and the remoteness of 
occupied habitat and limited flight period would make recreational 
collections difficult (Borkin 2012, pers. comm.). Therefore, 
overutilization for commercial, recreational, scientific, or 
educational purposes is not currently a threat to Dakota skipper and 
Poweshiek skipperling.
    Handling stress during scientific study may be stressors to 
individuals of both species. Adverse effects on butterflies have been 
documented for a wide range of species (e.g., Benson and Emmel 1973, p. 
329; Singer and Wedlake 1981, pp. 215-216; Lederhouse 1982, pp. 381-
382; Morton 1984, pp. 56-57; Mallet et al. 1987, pp. 380-383).
    Although recreational collection is not a threat to these species 
at this time, due to the few populations, small population size, and 
restricted range, if any recreational collecting did occur in the 
future, even limited collection from the remaining small and isolated 
populations could have deleterious effects on these species' 
reproductive and genetic viability.

Factor C. Disease or Predation

    Diseases or parasites that are specific to the Dakota skipper or 
Poweshiek skipperling are not known, but some parasitism or predation 
likely occurs during each of the life stages. Disease and predation are 
part of the natural population dynamics of any insect, including the 
Dakota skipper and Poweshiek skipperling--without high rates of 
mortality before reproduction, populations would increase 
exponentially. The small amount of observations of predation and 
parasitism makes documenting those phenomenons difficult (Dana 2013, 
pers. comm.). Only a few studies have attempted to document parasitism 
and predation. For example, 10 of 130 eggs tagged for field observation 
in a 1994 study of a Wisconsin Poweshiek skipperling population 
appeared to have suffered from predation or parasitism (Borkin 1995, p. 
5); some were punctured and had the contents extracted, and others 
turned black and dried up. Dana (1991, pp. 19-21) documented some 
parasitism of Dakota skipper and Ottoe skipper (Hesperia ottoe) eggs 
and larvae by various wasp species and predation by various insects, 
such as ants, but escaping his observation would have been predation by 
birds and small mammals on these immature stages (Dana 2013, pers. 
comm.).
    Wolbachia, ubiquitous intercellular bacteria estimated to affect 
20-70 percent of all insect species, including many butterfly species, 
affects the reproductive ecology of its host (Kodandaramaiah 2011, pp. 
343-350). It is uncertain if Wolbachia are affecting the Dakota skipper 
or Poweshiek skipperling. An infection of Wolbachia may reduce already 
small population sizes and increase the probability of extirpation 
(Nice et al. 2009, pp. 3137-3138), particularly if the population is 
infected with a novel strain (Runquist 2013, pers. comm.). The 
Minnesota Zoo plans to conduct Wolbachia screening and strain 
identification of genomic DNA samples that the University of Michigan 
(at Dearborn) extracted from both species. The effects of predation by 
birds or insects on Dakota skipper or Poweshiek skipperling population 
dynamics are not known and may impact the species.
    McCabe (1981, p. 187), noted three kinds of predators to Dakota 
skippers, including Ambush bugs (Hemiptera: Phymata sp.), flower 
spiders (Aranaea: Misumena spp.), and orb weavers (various Araneldae). 
Flower spiders and ambush bugs are effective predators of nectar-
feeding insects (McCabe 1981, pp. 187-188) and may cause mortality to 
some individuals, but it is difficult to quantify the population-level 
impacts of predators to either the Dakota skipper or Poweshiek 
skipperling. Dana documented predation on adult skippers by robber 
flies (Asilidae), which are common in upland prairie habitats, and 
noted the incidence of wing damage indicative of an unsuccessful attack 
by a bird or similar predator (Dana 1991, pp. 26-27; Dana 2013, pers. 
comm.). Several incidences of predation by crab spiders and robber 
flies on both the Dakota skipper and Poweshiek skipperling have been 
documented in Canada, although it is not thought to be a common 
occurrence (Westwood 2013, pers. comm.). McCabe (1981) failed to 
observe bird or dragonfly predation; however these events are difficult 
to observe (Dana 2013, pers. comm.). Orb weaver spiders appear to be 
successful predators of ``old, worn individuals'' (McCabe 1981, p. 
188), but bird and other animal predation on young and old adults 
likely occurs when the butterflies are roosting or torpid and unable to 
escape (Dana 1991, p. 27).
    Disease, parasitism, and predation are important parts of 
population dynamics of normal populations of insects, but may have an 
amplified effect on small populations. Furthermore, as we discuss in 
the possibility of unknown factors that may be affecting the species 
(in Factor E of this final rule), it is possible that a new virulent 
pathogen or parasitoid may have increased mortality above normal levels 
and may be causing the rapid decline in the Poweshiek skipperling and 
possibly also the Dakota skipper (Dana 2013, pers. comm.).
    Disease and parasitism are a serious hypothesis that may explain 
the rapid decline of the Poweshiek skipperling, and perhaps the Dakota 
skipper, and these factors, along with predation, are extremely 
difficult to observe. Therefore, we are unsure if either disease, 
parasitism, or predation are

[[Page 63733]]

significant stressors to the Dakota skipper or Poweshiek skipperling 
populations at this time, and we are not certain if these stressors 
will contribute to significant population-level impacts in the future. 
However, in the future, disease, parasitism, and predation may have an 
amplified effect on these small and isolated populations.

Factor D. The Inadequacy of Existing Regulatory Mechanisms

    Existing regulatory mechanisms vary by location, but generally do 
not mitigate for the numerous stressors that the Dakota skipper and 
Poweshiek skipperling face.
State Regulations
    The Dakota skipper is listed as endangered under Minnesota's 
endangered species statute. Under the Minnesota statute, a person may 
not take, import, transport, or sell any portion of an endangered 
species of wild animal or plant, or sell or possess with intent to sell 
an article made with any part of . . . an endangered species of wild 
animal or plant'' except as permitted by the Minnesota DNR (Minnesota 
Statutes 2012, 84.0895). The Poweshiek skipperling was listed as State-
endangered in Minnesota, and the status of Dakota skipper was changed 
from threatened to endangered on August 19, 2013 (Minnesota DNR 2013). 
The Poweshiek skipperling is listed as threatened under State 
endangered species statutes in Iowa and Michigan and as endangered in 
Wisconsin. The Dakota skipper is listed as endangered under State 
endangered species statutes in Iowa. South Dakota has an endangered 
species act, but no invertebrates are currently listed. South Dakota 
put forth a proposal to add the Dakota skipper to the State endangered 
species act list, but it was not finalized. Although the Dakota skipper 
is not listed as threatened or endangered under South Dakota's 
endangered species statute, the State natural heritage program 
considers the species to be imperiled because of rarity due to very 
restricted range and very few populations. North Dakota does not have a 
mechanism for conferring protection to threatened or endangered species 
at the State level.
    State endangered species statutes provide State natural resource or 
conservation agencies with the authority to regulate collection of 
individuals and related activities (for Poweshiek skipperling in Iowa, 
Michigan, and Wisconsin and Dakota skipper in Minnesota and Iowa), but 
we have no information to suggest that collection is a stressor that 
impacts populations of the species. With the exception of the 
regulation of some incidental take in Wisconsin and Minnesota, the 
statutory protections afforded by these State statutes may do little to 
protect or mitigate Poweshiek skipperling or Dakota skipper from non-
collection threats. While some stressors may result in direct mortality 
of both species, such as ill-timed fires, most stressors to the species 
are indirect and State laws that regulate direct harm to the species do 
not address these factors. In Iowa, for example, Poweshiek skipperling 
populations are likely now extirpated due to habitat destruction and 
conversion and other undetermined stressors, despite the species' 
presence on the State's list of threatened species since 1994. In 
Wisconsin, where stressors from actions that may incidentally take 
Poweshiek skipperlings may be addressed in conservation plans, State 
endangered species protections do not protect the species from 
stochastic events and habitat fragmentation that are stressors to the 
State's small and isolated populations.
    In North Dakota, the fundamental purpose of the North Dakota 
Trustlands (e.g., State school lands) management is to obtain a ``fair 
market'' return from the lands while maintaining or improving their 
condition and value (ND Department of Trustlands Web site http://www.land.nd.gov/surface/About.aspx). Consequently, if such land does 
not produce income for the State, it may be subjected to deliberate 
change in management strategy or ownership (e.g., sale at auction). The 
major source of income on the North Dakota Trustlands is from grazing 
and agricultural leases, with additional revenue generated from rights-
of-way, salt water disposal, and gravel and scoria mining (ND 
Department of Trustlands Web site http://www.land.nd.gov/surface/About.aspx). At least two Dakota skipper sites are under North Dakota 
State School management and are managed as hay lands.
Federal Regulations
    The U.S. Forest Service (Forest Service or USFS) has designated the 
Poweshiek skipperling and the Dakota skipper as sensitive species (a 
species identified by a Regional Forester for which population 
viability is a concern) in North Dakota (Forest Service 2011). The 
Forest Service's objectives for sensitive species benefit Dakota 
skipper and Poweshiek skipperling where they occur (or could occur) on 
USFS lands; however, the majority of populations of both species do not 
occur within USFS lands. The Poweshiek skipperling has been documented 
at two sites on the Sheyenne National Grasslands; however, it has not 
been observed since 2001 at one site and 1996 at the other. Therefore, 
these Forest Service objectives, although promising, have little 
ability to affect the rangewide status of the species. If Forest 
Service lands were to be occupied by either species in the future, 
these objectives may benefit the species at a local scale.
Canadian Regulations
    Dakota skipper and Poweshiek skipperling are listed as threatened 
under Canada's Species at Risk Act (SARA) (Environment Canada 2012. 
Species at Risk Act Public Registry. <http://www.registrelep-sararegistry.gc.ca/sar/index/default_e.cfm>. Accessed September 19, 
2014). Under SARA, take of both species is prohibited on Canadian 
Federal lands, but the Poweshiek skipperling occurs only on non-Federal 
lands in Canada, and only four or five Dakota skipper sites are on 
Federal lands (Coalfields Community Pasture) in Canada. The Federal 
Cabinet may create an order extending SARA's powers (e.g., to private 
lands) if a species is insufficiently protected by provincial laws; 
however, such action has not been taken for either of these species. In 
May 2014, the COSEWIC status designation of Dakota skipper was changed 
from threatened to endangered (http://www.cosewic.gc.ca/rpts/detailed_species_assessments_e.html accessed September 19, 2014). The 
Dakota skipper is listed as threatened under the Manitoba Endangered 
Species Act, and it is, therefore, unlawful to kill, injure, possess, 
disturb, or interfere with the Dakota skipper; destroy, disturb, or 
interfere with its habitat; or damage, destroy, obstruct, or remove a 
natural resource on which the species depends for its life and 
propagation (Manitoba Endangered Species Act http://www.gov.mb.ca/conservation/wildlife/legislation/endang_act.html, accessed February 7, 
2012). The Poweshiek skipperling was recently listed as endangered in 
Manitoba (http://www.gov.mb.ca/conservation/wildlife/sar/sarlist.html, 
accessed December 28, 2012). There is no legal basis for protecting 
threatened or endangered invertebrates in Saskatchewan, but since both 
species are listed under SARA, the national government could step in to 
protect the species in the province if the province does not act to 
protect the species (Environment Canada. 2012. Species at Risk Act: A 
Guide. http://www.sararegistry.gc.ca/approach/act/

[[Page 63734]]

Guide_e.cfm, accessed February 7, 2012).
    To summarize, some of the regulatory mechanisms discussed above are 
beneficial to populations of Dakota skipper and Poweshiek skipperling 
at a local scale; however, most do not ameliorate stressors except for 
harm to individuals in certain States. With the exception of the 
regulation of some incidental take in Wisconsin, Minnesota, and Canada, 
the statutory protections afforded by these statutes may do little to 
protect Poweshiek skipperling or Dakota skipper from non-collection 
stressors.

Factor E. Other Natural or Manmade Factors Affecting Its Continued 
Existence

Habitat Fragmentation and Population Isolation
    As habitat specialists, habitat fragmentation has a strong negative 
effect on the distribution and abundance of the Dakota skipper and 
Poweshiek skipperling because both are dependent on remnant native 
tallgrass prairie or native mixed-grass prairie, and, in Michigan, 
Poweshiek skipperling depends on native prairie fens. Habitat 
fragmentation reduced once-extensive areas of these habitats to a 
collection of patches of varying quality and isolation. The probability 
of extinction within patches can be determined primarily by degradation 
of habitat quality, management techniques (e.g., haying, prescribed 
burns), and likelihood of stochastic events, such as wildfire or 
floods.
    Fragmentation of tallgrass prairie has degraded the genetic 
diversity of remaining Dakota skipper populations (Britten and Glasford 
2002, pp. 371-372). What may have once been a single population of 
Dakota skippers spread across formerly extensive tallgrass and mixed-
grass prairie (McCabe 1981, p. 184) is now fragmented into about 171 
separate sites where the species is known to be or may still be present 
(sites with present (83) or unknown (88) status). The small genetic 
differences among seven Dakota skipper populations in the southern 
portion of the species' range suggest that they were formerly connected 
(Britten and Glasford 2002, pp. 371-372). Each Dakota skipper 
population is now subject to genetic drift that may erode its genetic 
variability over time and possesses genetic qualities indicative of 
inbreeding (Britten and Glasford 2002, pp. 371-372). Inbreeding lowers 
the capacity of local populations to adapt to environmental changes and 
may magnify the effect of deleterious alleles (genes with undesirable 
effects on individuals or populations) (Nieminen et al. 2001, pp. 242-
243).
    Preliminary results of genetic studies on the Poweshiek skipperling 
show that there appears to be limited levels of genetic diversity in 
the 32 tissue samples that were collected from the Scuppernong Prairie 
site in Wisconsin, 7 samples from Manitoba, and 93 from 6 Michigan 
populations in 2012 (Saarinen 2013, pers. comm.). Of greater concern 
than loss of genetic diversity, however, may be demographics, 
specifically the limited number of populations and population sizes 
that may be too small to persist (Saarinen 2013, pers. comm.) 
compounded by other stressors.
    Poweshiek skipperlings are not wide dispersers (Burke et al. 2011, 
p. 2279; Fitzsimmons 2012, pers. comm.); species experts have estimated 
maximum dispersal distance to be less than 1.6 km (1.0 mi) (Westwood 
2012b, pers. comm; Dana 2012b, pers. comm.). Its mobility, however, has 
been ranked as less than that of Dakota skipper (Burke et al. 2011, p. 
2279; Fitzsimmons 2012, pers. comm.); therefore, a more conservative 
maximum dispersal distance may be more similar to that of the Dakota 
skipper (less than 1 km (0.6 mi)). Most individuals may remain within a 
single habitat patch during their 5-7 day adult life span; therefore, 
local extinctions of the Poweshiek skipperling on isolated habitat 
fragments are likely permanent unless one or more populations located 
within 1.0-1.6 km (0.6-1.0 mi) are large enough to produce immigrants 
to reestablish populations. Furthermore, fragmentation of tallgrass 
prairie began in about 1830, and at least 85 to 99 percent of the 
original prairie is now gone across the species' ranges (Samson and 
Knopf 1994, p. 419). As a result, Poweshiek skipperling and Dakota 
skipper populations are now scattered in fragments of this once-vast 
ecosystem. The Poweshiek skipperling may not move across barriers; for 
instance, in Manitoba, Poweshiek skipperlings have been observed 
avoiding dispersal over short distances, even to suitable habitat, if a 
barrier such as a road exists between suitable prairie habitat or 
nectar sources (Westwood et al. 2012, p.18). Repopulation of Poweshiek 
skipperling sites after extirpation has been observed (e.g., after a 
flood) (Saunders 1995, p. 15), but source populations need to be 
adjacent or very close.
    Similarly, adult Dakota skippers have a short (5- to 7-day) life 
span (Dana 1991, p. 32) and an estimated maximum dispersal distance to 
be no greater than 1 km (0.6 mi) between patches of prairie habitat 
separated by structurally similar habitats (Cochrane and Delphey 2002, 
pp. 6, 32). Therefore, Dakota skipper and Poweshiek skipperling habitat 
patches separated by more than 1 km (0.6 mi) are effectively isolated 
from one another (McCabe 1981, p. 190; Swengel 1998). Extirpation of 
small, isolated populations may occur over many years in some cases, 
but may be inevitable where immigration from nearby populations is not 
possible (Hanski et al. 1996, p. 535).
    Because Dakota skipper and Poweshiek skipperling habitat is highly 
fragmented and because the species are subject to local extinction, 
their ability to disperse to reoccupy vacant habitat patches may be 
crucial for their long-term persistence. Patch isolation and decreased 
permeability of surrounding habitat acts as a dispersal barrier between 
patches, ultimately decreasing genetic diversity within the patch 
through genetic drift and inbreeding. If we assume isolation occurs 
when a patch is more than 1.6 km (1.0 mi) from another patch, then 
about 45 percent of Poweshiek skipperling locations with present or 
unknown status are effectively isolated, and would not be recolonized 
if extirpated (Service 2012 unpubl. data; Service 2014, unpubl. data). 
Using a more conservative maximum dispersal of 1.0 km (0.6 mi), 
approximately 55 percent of Poweshiek skipperling locations with 
present or unknown status are effectively isolated. Isolation was a 
factor in loss of a site at Hartford Beach State Park, South Dakota, 
where the Poweshiek skipperling was extirpated due to habitat 
succession and exotic plant invasion (Skadsen 2009, p. 4; Skadsen 2010, 
pers. comm.), but was located too far from a source population for 
natural recolonization to occur. Improved prairie management has since 
markedly improved habitat quality, but the species has not been 
detected since 2006 at Hartford Beach State Park (Skadsen 2009, p. 4; 
Skadsen 2012, p. 4; Service 2014, unpubl. geodatabase). For Dakota 
skipper, if we use a maximum dispersal distance of 1 km (0.6 miles), 
approximately 63 percent of Dakota skipper sites with present or 
unknown status are effectively isolated (Service 2014, unpubl. 
geodatabase).
    This simple analysis, however, probably underestimates the impacts 
of habitat fragmentation on the species. Populations of both species 
may only be near others that are too small to produce sufficient 
numbers of immigrants. This is true for the Poweshiek skipperling in 
Scuppernong Prairie in Wisconsin, for example, which is about 0.3 km 
(0.2 mi)

[[Page 63735]]

from the Wilton Road population; fewer than 100 individuals have been 
counted at this site each year, and the species was not observed in 
2013 (See Population Distribution and Status). Numbers at Wilton Road 
are currently too small (fewer than 12 individuals counted each year) 
to produce sufficient numbers of emigrants to Scuppernong Prairie to 
reestablish a viable population in the event of the latter's 
extirpation. There is no population of Poweshiek skipperlings near the 
Puchyan Prairie site (which is about 115 km (71 mi) from the nearest 
site in Wisconsin); additionally, only a few individuals have been 
observed at this site each year. In North Dakota, Orwig (1997, p. 3) 
found that a 6-ha (15-ac) patch of Poweshiek skipperling habitat at 
Hartleben Prairie was connected by grassland to another Poweshiek 
skipperling population, but neither was considered a robust population 
at the time and the species was not observed at either location in 
2013. Only 2 of the 9 Poweshiek skipperling sites with present status 
in Michigan are located within 1.6 km (1 mi) of another site; the rest 
are completely isolated from other populations. Furthermore, most of 
these populations consist of few individuals (see Population 
Distribution and Status). Poweshiek skipperlings at Little Goose Lake 
Fen, for example, are separated from other populations by at least 8 km 
(5 mi)--too far for immigrants to repopulate the site. Furthermore, 
Little Goose Lake Fen may contain too few Poweshiek skipperlings 
(Michigan Natural Features Inventory 2011, unpubl. data; Cuthrell 2013, 
pers. comm.) to generate sufficient numbers of immigrants. In addition, 
poor habitat quality negatively influences the number and quality of 
emigrants (Thomas et al. 2001, p. 1795; Matter et al. 2009, p. 1467). 
Isolation is not likely alleviated by connections to low-quality 
habitats that are not capable of producing emigrants at the numbers or 
frequency sufficient to reliably repopulate nearby patches.
    Even with proper prairie management at individual sites, extreme 
weather patterns or severe weather events may significantly impact 
Poweshiek skipperling and Dakota skipper populations, because they can 
occur across a large geographic area. These events include extremely 
harsh winters, late hard frosts following a spring thaw, severe storms, 
flooding, fire, or cool damp conditions. Habitats isolated as a result 
of fragmentation will not be recolonized naturally after local 
extirpations, as described above. Dakota skipper and Poweshiek 
skipperling numbers may decline due to the extirpation of isolated 
local populations where recolonization is no longer possible, even 
without further habitat destruction (Schweitzer 1989, unpaginated). The 
likelihood of population extirpation may be directly related to the 
size of habitat fragments. For example, in systematic surveys on 
Minnesota prairies, Swengel and Swengel (1997, pp. 134-137; 1999, p. 
284) found no Dakota skippers on the smallest remnants (less than 20 ha 
(49 ac)), and significantly lower abundance on intermediate size (30-
130 ha (74-321 ac)) than on larger tracts (greater than 140 ha (346 
ac)). These differences were unrelated to vegetation characteristics; 
habitat area did not correlate significantly with vegetation type, 
quality, or topographic diversity (Swengel and Swengel 1999, p. 284).
    We assessed the stressor of small size and isolation of habitat for 
163 Dakota skipper sites and 54 Poweshiek skipperling sites with 
present or unknown status (Service 2012 unpubl. data; Service 2014, 
unpubl. data). We considered small size and isolation of habitat to be 
a stressor with a low-level impact on populations at sites that contain 
more than 140 ha (346 ac) of native prairie or the species' habitat 
onsite is located less than 1 km (0.6 mi) from habitat occupied by the 
species on another site. If the sum of native prairie on the site under 
review plus that on the nearby site(s) is less than 140 ha (346 ac), 
then this stressor was considered to have a moderate or high impact on 
populations. We considered small size and isolation of habitat to be a 
stressor with moderate impacts on populations at sites where the 
species' habitat is greater than 1 km (0.6 mi) from any other area 
where the species is present, but contains more than 30 ha (74 ac) of 
habitat for the species; or where the species' habitat is less than 1 
km (0.6 mi) from occupied Dakota skipper and Poweshiek skipperling 
habitat on another site, but the sum of native prairie on the site 
under review plus that on the nearby site(s) is less than 140 ha (346 
ac) and greater than 30 ha (74 ac). Sites that contain a small area of 
Dakota skipper and Poweshiek skipperling habitat--no more than 30 ha 
(74 ac)--and that are not within the 1-km (0.6-mi) estimated maximum 
dispersal distance of occupied Dakota skipper habitat are considered to 
have a stressor of high magnitude to those populations due to a 
combination of their small size and isolation.
    Although we were unsure of the size of many sites in Canada, most 
sites were separated by more than 1 km (0.6 mi). Dakota skipper sites 
in central Manitoba are generally greater than 158 ac (64 ha), but all 
of the sites are separated by more than 1 km (0.6 mi), and many sites 
are separated by many kilometers (Westwood 2013 pers. comm.). 
Therefore, about 25 of the sites evaluated in Canada were thought to 
have at least a moderate level of stressor from size and isolation. The 
Canada sites where Dakota skippers are considered to be present are 
approximately 200 km (125 mi) from the nearest North Dakota site, and 
the Manitoba site is 166 km (103 mi) from the nearest Poweshiek 
skipperling site in Minnesota.
    Dakota skipper populations on about 31 percent of the evaluated 
sites (50 of 163 sites) face a high level of impact due to a 
combination of size and isolation (Service 2012 unpubl. data, 2014 
unpubl. data). Approximately 31 percent of evaluated sites (50 sites) 
face a moderate level of impact to populations due to small size and 
isolation. About 39 percent of Dakota skipper sites (63 of the 163 
evaluated sites) in the United States are either sufficiently large 
(greater than 130 ha (346 ac)) or are close enough to other Dakota 
skipper populations that small size and isolation is not a stressor. 
Similarly, the stressor of small size and isolation has a high level of 
impact on Poweshiek skipperling populations on about 39 percent of 
rated sites (25 of 54 sites), on 22 sites (41 percent) the stressor is 
considered to have a moderate level of impact to populations, and on 20 
percent (11 of the 54 evaluated sites) of the sites, we do not consider 
a small size and isolation to be a stressor. In a separate analysis 
strictly looking at distances between Poweshiek skipperling sites where 
the species is present, we found that only 4 sites are within 1 km (0.6 
mi) of another site where the species is present (Service 2014, unpubl 
geodatabase).
    In summary, small, isolated populations face a current and ongoing 
stressor of moderate to high severity to both the Dakota skipper and 
Poweshiek skipperling. The stressor has a high impact to populations 
when isolation is combined with small habitat fragments or small 
populations; for example, where the population is too small to 
supplement nearby populations without adverse genetic consequences to 
the source population. Isolated populations occur throughout both 
species' entire ranges; only 4 of the 12 Poweshiek sites with present 
status are within the estimated maximum dispersal distance from one 
another as are about 40 percent (64-69 of 171 sites) of Dakota skipper 
sites with present or unknown occupancy. The small populations are

[[Page 63736]]

subject to erosion of genetic variability leading to inbreeding, which 
lowers the ability of the species to adapt to environmental change. 
Small populations occur rangewide for both species; for example, 
surveyors have counted fewer than 100 individuals in all but 4 
Poweshiek skipperling sites in 2011, all but one site surveyed in 2012, 
and all sites surveyed in 2013.
Climate Change
    Our analyses under the Act include consideration of the likely 
effects of ongoing and projected changes in climate. The terms 
``climate'' and ``climate change'' are defined by the Intergovernmental 
Panel on Climate Change (IPCC). ``Climate'' refers to the mean and 
variability of different types of weather conditions over time, with 30 
years being a typical period for such measurements, although shorter or 
longer periods also may be used (IPCC 2013, p. 1450). The term 
``climate change'' thus refers to a change in the mean or variability 
of one or more measures of climate (e.g., temperature or precipitation) 
that persists for an extended period, typically decades or longer, 
whether the change is due to natural variability, human activity, or 
both (IPCC 2013, p. 1450). Various types of changes in climate can have 
direct or indirect effects on species. These effects may be positive, 
neutral, or negative and they may change over time, depending on the 
species and other relevant considerations, such as the effects of 
interactions of climate with other variables (e.g., habitat 
fragmentation) (IPCC 2007, pp. 8-14, 18-19). We use our expert judgment 
and appropriate analytical approaches to weigh relevant information, 
including uncertainty, in our consideration of various aspects of 
climate change.
    As is the case with all stressors that we assess, even if we 
conclude that a species is currently affected or is likely to be 
affected in a negative way by one or more climate-related impacts, it 
does not necessarily follow that the species meets the definition of an 
``endangered species'' or a ``threatened species'' under the Act. If a 
species is listed as endangered or threatened, knowledge regarding the 
vulnerability of the species to, and known or anticipated impacts from, 
climate-associated changes in environmental conditions can be used to 
help devise appropriate strategies for its recovery.
    Global climate change, with projections of increased variability in 
weather patterns and greater frequency of severe weather events, as 
well as warmer average temperatures, would affect remnant prairie 
habitats and prairie fen habitats and may be a stressor that has 
significant impacts on prairie butterflies such as Dakota skippers and 
Poweshiek skipperling (Royer and Marrone 1992b, p. 12; Royer and 
Marrone 1992a, pp. 22-23; Swengel et al. 2011, p. 336; Landis et al. 
2012, p. 140). For example, climatic factors, particularly 
precipitation and evaporation, play an important role in defining 
suitable Dakota skipper habitat (McCabe 1981, pp. 189-192). Larval 
Dakota skipper have ``hydrofuge glands'' that suggest an historical or 
present need of the species for protection from flooding (McCabe 1981, 
p. 181). Royer et al. (2008, p. 2) hypothesize that temperature and 
relative humidity at or near the soil surface may be important factors 
dictating larval survival, particularly since early stages live in a 
silken nest within a few centimeters (2-3) (0.8-1.2 in) of the soil 
surface during most of the summer (McCabe 1981, pp. 180-181, 189; Dana 
1991, p. 16). Furthermore, both species and their habitats may 
experience the effects of gradual shifts in plant communities and an 
increase in catastrophic events (such as severe storms, flooding, and 
fire) due to climate change, which are exacerbated by habitat 
fragmentation. Isolated populations, specifically, Dakota skipper 
populations and Poweshiek skipperling populations that are separated by 
more than about 1 km (0.6 miles), are unlikely to recover from local 
catastrophes unless sufficient numbers are successfully reintroduced, 
for instance, through artificial propagation efforts.
    Documentation of climate-related changes that have already occurred 
throughout the range of the Dakota skipper and Poweshiek skipperling 
(Johnson et al. 2005, pp. 863-871) and predictions of changes in annual 
temperature and precipitation in the Midwest region of the United 
States, such as Minnesota prairies (Galatowitsch et al. 2009, pp. 
2017), Michigan fens (Landis et al. 2012, p. 140), South Dakota 
(Cochrane and Moran 2011, entire), and throughout North America (IPCC 
2007, p. 9) indicate that increased severity and frequency of droughts, 
floods, fires, and other climate-related changes will continue in the 
future. Recent studies have linked climate change to observed or 
predicted changes in distribution or population size of insects, 
particularly Lepidoptera (Wilson and Maclean 2011, p. 262). Native 
remnant prairies have been reduced by 85 to 99.9 percent across the 
range of both species (Samson and Knof 1994, p. 419)--this fact, 
coupled with the low dispersal ability of both species, makes it 
unlikely that populations may expand to new areas, for example, in a 
northward direction, to adapt to changing climate. Climate change is a 
stressor that has the potential to have severe impacts on the species; 
however, at this time our knowledge of how these impacts may play out 
is limited. All of the sites within the range of both species are in an 
area that will experience the effects of climate change, but how those 
effects will be manifested is uncertain.
Prairie Plant Harvesting
    A potential, future stressor to the Dakota skipper and Poweshiek 
skipperling is collection of purple coneflower (also known as black 
samson echinacea), a predominate nectar source for both species, for 
the commercial herbal remedy market (Skadsen 1997, p. 30). Biologists 
surveying skipper habitats have not reported signs of plant collecting, 
but illegal or unregulated harvest could become a problem in Dakota 
skipper and Poweshiek skipperling habitats due to economic demand 
(Skadsen 1997, p. 30). Currently, prairie plant harvesting is not 
considered a threat that impacts the species; however, this situation 
may change if the demand for echinacea increases.
Management for Invasive Species and Succession
    Native prairie and native prairie fens must be managed to prevent 
the indirect effects of invasive species and succession (processes of 
change in species structure to an ecological community over time; 
secondary succession is a disruption to succession that occurs due to 
an event such as fire) to Dakota skippers and Poweshiek skipperlings. 
If succession progresses too far, established shrubs or trees must be 
removed in a way that avoids or minimizes damage to the native prairie. 
When succession is well advanced, managers must use intensive methods, 
such as fire management, to restore prairie plant communities. If not 
done carefully, these actions may themselves harm local populations of 
the butterflies (for example, see Factor A. The Present or Threatened 
Destruction, Modification, or Curtailment of Its Habitat or Range). For 
example, once smooth brome has invaded Poweshiek skipperling or Dakota 
skipper habitat, it is challenging to eradicate it while minimizing 
harm to the butterflies. Willson and Stubbendiecks (2000, p. 36) 
recommended burning prairie habitats, annually in some cases, to 
control smooth brome at the stage when the lateral shoots are 
elongating.

[[Page 63737]]

    In southwestern Minnesota and in other parts of Dakota skipper's 
range, the optimum time to burn to control smooth brome may occur 
during the time that the adult butterflies are active. Cutting or 
grazing to remove smooth brome may have less intensive effects on 
Poweshiek skipperling and Dakota skipper larvae and could be used as an 
alternative to fire, although these techniques also pose a risk to both 
species if carried out annually at isolated sites. Puchyan Prairie is 
another example of a small and isolated population that is susceptible 
to invasive species control efforts, if they are not conducted properly 
(Swengel and Swengel 2012, p. 6), although the Wisconsin DNR proposed 
control efforts that may improve habitat by removing reed canary grass, 
Canada thistle, and glossy buckthorn (Wisconsin DNR 2012 in litt.; 
Carnes 2012, in litt.).
    If not appropriately managed with fire, grazing, or haying, 
Poweshiek skipperling and Dakota skipper habitat is degraded due to 
reduced diversity of native-prairie plants and eventually succeeds to 
shrubby or forested habitats that are not suitable for either species. 
At Hartford Beach State Park in South Dakota, for example, the 
Poweshiek skipperling was extirpated (Skadsen 2009, p. 4) after lack of 
management led to invasion by smooth sumac (Rhus glabra) and quaking 
aspen (Populus tremuloides) (Skadsen 2006a, p. 5). Lack of management 
may also increase the likelihood of invasion of exotic cool-season 
grasses, such as Kentucky bluegrass and smooth brome (Mueller 2013, 
pers. comm.), which do not grow when Dakota skipper and Poweshiek 
skipperling larvae are feeding; thus a prevalence of these grasses 
reduces food availability for the larvae.
    As with invasive species, actions intended to reverse secondary 
succession may be intensive and can themselves affect Poweshiek 
skipperling and Dakota skipper populations. For example, Poweshiek 
skipperling populations failed to recover after prescribed burns were 
carried out at Kettle Moraine Low Prairie SNA after it had become 
overgrown (Borkin 2011, in litt.).
    Although carefully targeted herbicide treatments result in 
beneficial control of undesired plants, broadcast chemical control of 
exotic plants such as aerial spraying of leafy spurge and application 
of broad-spectrum herbicides to control weeds in pastures also 
eliminates native forbs that are important nectar sources for both 
species (Royer and Marrone 1992a, pp. 10, 16, 28, 29, 33, 1992b, p. 17, 
Orwig 1997, p. 7). For example, invasion of native prairie by exotic 
species, primarily leafy spurge and Kentucky bluegrass, as well as 
chemical control of exotic species, are documented stressors to Dakota 
skippers at about 12 sites in North Dakota (Royer and Royer 2012b, pp. 
15-16, 22-23). In repeated surveys, Royer and Marrone (1992a, p. 33) 
observed a correlation between the disappearance of the Dakota skipper 
and the advent of chemical weed control methods in North Dakota, 
including the Sheyenne National Grasslands. Royer and Marrone (1992b, 
p. 17) cited the combination of drought and grasshopper control 
programs along the Red River Valley as having serious impacts on the 
Poweshiek skipperling. Dana (1997, p. 5) concluded that herbicide use 
for weed and brush control on private lands is the principal stressor 
to the Hole-in-the-Mountain complex in Minnesota, where both butterfly 
species have been documented.
    Furthermore, herbicide or pesticide use in concert with other 
management types may amplify other stressors to the butterflies. 
Skadsen (2006b, p. 11), for example, documented the likely extirpation 
of the Poweshiek skipperling at Knapp Ranch in South Dakota after a 
July 2006 application of broadleaf herbicide associated with heavy 
grazing. The degree and immediacy of the impact posed by broadcast 
application of herbicides or pesticides is not precisely understood, 
but may be mostly tied to the use of herbicides to control invasive 
species on rangelands. If broad applications of herbicides are used in 
ways that remove plants from rangelands that are important for 
Poweshiek skipperling or Dakota skipper, then this is a potential 
stressor on all privately owned sites where broadcast applications may 
occur.
    Indiscriminant use of insecticides for pest control on rangeland, 
adjacent cropland, or forests is a stressor to populations of Poweshiek 
skipperling and Dakota skipper. Insecticides used in agriculture, urban 
gardens, and forests are a suspected cause of Colony Collapse Disorder 
in bees by reducing resistance to parasites and pathogens and may have 
similar effects on other insects (Beyers 2012, p. 1). Neonicotinyl 
pesticides, such as the imidacloprid compound, for example, are a 
commonly used seed dressing that spreads to nectar and pollen of 
flowering crops (Whitehorn 2012, p. 1). The use of neonicotinoids on 
agricultural crops has dramatically increased in the last ten years and 
they are now the most widely used group of insecticides in the world 
(Jeschke et al. 2011, pp. 2897-2898; Main et al. 2014, p. 2; Goulson 
2013, pp. 1-2). Neonicotinoids persist in the environment (Goulson 
2013, p. 1) and are thought to accumulate in the soil from repeated 
applications over time (Hopwood et al. 2013, p. 4). Insects can be 
exposed through multiple routes--neonicotinoids are used in seed 
dressings, foliar spray, soil irrigation water, soil drench, granular 
in pastures, tree injections, and topical applications to pets.
    In the United States, six neonicotinoids are approved for use--
imidacloprid, thiamethoxam, clothianidin, dinotefuran, thiacloprid, and 
acetamiprid (EPA 2014 Web site)--and it is estimated that more than 3.5 
million pounds (56 million ounces) of neonicotinoids were applied to 
nearly 127 million acres (51 million hectares) of agricultural crops 
each year from 2009 to 2011. The presence and concentrations of 
neonicotinoids at Dakota skipper and Poweshiek skipperling sites or 
nearby agricultural fields that use neonicotinoid seed treatments or 
other such treatments has not been assessed, however, in general, 
nearly 100 percent of corn is known to be treated, and about 75 percent 
of soybean seeds are known to be treated with neonicotinoids, for 
example. Similarly, soybean aphid spraying occurs during the adult 
flight period, is widespread, and applied aerially--this spray can 
drift to nearby Dakota skipper or Poweshiek skipperling habitat. The 
presence and concentrations of insecticides at Dakota skipper and 
Poweshiek skipperling sites or nearby agricultural fields that utilize 
soybean aphid spraying has not been assessed. The Minnesota Zoo has 
proposed a study to investigate the levels of neonicotinoids, aphid 
pesticides, and other insecticides that may be present at several 
skipper sites in Minnesota and South Dakota.
    The spread of nonnative gypsy moths (Lymantria dispar dispar) has 
increased efforts to control this damaging species and may also be a 
stressor, especially in the range of Poweshiek skipperling. 
Insecticides used in the gypsy moth suppression programs typically 
include Foray, a formulation of the bacterial insecticide Bacillus 
thuringiensis kurstakii (Btk), or Gypchek, a viral insecticide specific 
to gypsy moth caterpillars. Btk is known to be lethal to butterfly 
larvae (e.g., Karner blue butterfly) (Carnes 2011, p. 1). In Wisconsin, 
the gypsy moth suppression program is managed under State Statute 26.30 
and Natural Resources Board Rule number 47, and Gypchek is used when 
endangered or threatened moths or butterflies are present (Wisconsin 
DNR, http://dnr.wi.gov/topic/ForestHealth/

[[Page 63738]]

GypsyMothPesticides.html, accessed May 24, 2012).
    Herbicide and pesticide use was assessed at 15 present and unknown 
Dakota skipper sites and 9 Poweshiek skipperling sites occupied with 
present or unknown occupancy where we had sufficient information to 
evaluate the stressor (Service 2012 unpubl.; 2014, unpubl. data). We 
considered the level of impact to populations posed by herbicide and 
pesticide use to be low if the site is only spot sprayed with 
herbicides or pesticides when and where necessary (Smart et al. 2011, 
p. 182) and their use is not expected to change in the future. The 
level of stressor was considered to be moderate if the use of 
herbicides is likely to increase at a site (e.g., in response to new or 
expanding invasive species), but Dakota skipper and Poweshiek 
skipperling habitat is unlikely to be exposed to broadcast 
applications. The level of impact to populations posed by herbicide and 
pesticide use was considered to be high at sites where herbicides are 
likely to be broadcast over the entire site at least once every 4 
years, or herbicide use has significantly reduced forb or nectar plant 
density and diversity or is likely to in the future. The level of 
impact to populations posed by herbicide and pesticide use was high at 
5 of the 16 assessed Dakota skipper sites (2 in North Dakota and 3 in 
South Dakota) and moderate at 2 sites--1 in North Dakota and 1 in South 
Dakota. The level of impact to populations posed by herbicide and 
pesticide use was considered to be high at 3 of the 9 assessed 
Poweshiek skipperling sites (all 3 in South Dakota), and 1 site in 
North Dakota had a moderate level of impact to populations.
    In summary, some efforts to manage woody encroachment and invasive 
species, such as herbicide use, can be a stressor to both Dakota 
skipper and Poweshiek skipperling populations. Invasive species 
management is a current and ongoing stressor of low to high impact to 
populations, depending on the intensity and extent of the use, types of 
techniques, and the compounding effects that may occur from varying 
management. Medium- to high-level impacts of herbicide or pesticide use 
to Dakota skipper and Poweshiek skipperling populations have been 
documented in North and South Dakota. This stressor has a high impact 
to populations when it is combined with other stressors, such as 
management, that reduces or eliminates nectar food sources, or small 
habitat fragments that are isolated from other source populations that 
may replenish individuals killed by pesticides. Herbicide and pesticide 
use may have direct or indirect effects on Dakota skipper and Poweshiek 
skipperling. Although such activities occur, there is no evidence that 
these activities alone have significant impacts on either species, 
since their effects are often localized. However, these factors may 
have a cumulative effect on the Dakota skipper and Poweshiek 
skipperling when added to habitat curtailment and destruction because 
dramatic population declines have occurred in both species (discussed 
in Factor A). Invasive species and woody vegetation management helps to 
maintain prairie habitats and can also be beneficial to populations of 
both species, for example, when concentrated on affected areas through 
spot spraying.
Pharmaceuticals
    The effect of pharmaceutical residues in the environment on 
nontarget animals is an emerging concern (Lange et al. 2009). 
Ivermectin, a widely used and persistent veterinary pharmaceutical used 
to treat cattle, is a chemical of emerging concern to the Dakota 
skipper and Poweshiek skipperling. Ivermectin is an anthelmintic (drugs 
that are used to treat infections with parasitic worms) that is spread 
to prairie environments via the dung of grazing cattle (Lange et al. 
2009, p. 2238). Lange et al. (2009, pp. 2234, 2238) found that skipper 
butterflies are particularly vulnerable to ivermectin, due to their low 
dispersive capacities and habitat preferences for soil. The extirpation 
of the Dakota skipper in at least one South Dakota site (Sica Hollow 
West) is possibly due to ivermectin that has leached into the 
environment (Skadsen 2010, pers. comm.).
    Pharmaceutical use is a stressor that has the potential to have 
high-level impacts on populations of the Dakota skipper and Poweshiek 
skipperling; however, at this time our knowledge of these impacts is 
limited. Sites within the range of both species could experience the 
effects of pharmaceuticals. Sites that experience grazing, however, are 
particularly vulnerable to ivermectin use; these sites are primarily in 
South Dakota, North Dakota, and Minnesota. The use of pharmaceuticals 
such as ivermectin may have a cumulative effect on the Dakota skipper 
and Poweshiek skipperling when added to habitat curtailment or 
destruction, because habitat destruction leads to population declines 
in populations of both species (discussed in Factor A).
Unknown Stressors Causing Population Declines
    The sharp and broad declines of Poweshiek skipperling documented in 
Iowa, Minnesota, North Dakota, and South Dakota are indicative of a 
response to one or more stressors that have yet to be ascertained. 
These unknown factors may consist of a combination of one or more of 
the stressors described throughout Factors A, C, and E of this final 
rule, or may be something that has not yet been identified. These 
declines are reminiscent of the widely publicized decline of honey bees 
(Apis mellifera) in that they seem sudden and mysterious (Spivak et al. 
2011, p. 34). One hypothesis to explain the rapid decline of the 
Poweshiek skipperling, and possibly the Dakota skipper, is that a newly 
virulent pathogen or a new parasitoid has increased mortality above 
normal levels (Dana 2013, pers. comm.).
    One or more unidentified stressors have strongly impacted Poweshiek 
skipperling populations in the western portion of its range, which 
contains more than 80 percent of the species' site records. Unknown 
stressors may be the current factor with the most significant impacts 
to Poweshiek skipperling in Minnesota, North Dakota, and South Dakota, 
where populations experienced a sudden decline to undetectable numbers 
after about 2003. Until about 2003, Poweshiek skipperling was regarded 
as the most frequently and reliably encountered prairie-obligate 
skipper in Minnesota, which contains nearly 50 percent of all known 
Poweshiek skipperling locations. Numbers and distribution dropped 
dramatically in subsequent years, however, and the species has not been 
seen in Minnesota since 2007, with the exception of 2 individuals 
observed at one location in 2013 (Weber 2014, in litt.; Dana 2014, 
pers. comm.). Similar recent dramatic declines were observed in North 
Dakota, South Dakota, and Iowa (See Background of this rule).
    Recent declines of Dakota skippers indicate that this species may 
also be impacted by unknown stressors. The Dakota skipper was last 
detected at one site in Iowa in 1992. Only one individual was detected 
in Minnesota during 2012 surveys, which included 18 sites with previous 
records; surveys for undiscovered populations were also carried out on 
23 prairie remnants without previous records for the species. Only six 
individual Dakota skippers were detected at one site in Minnesota 
during 2013 surveys, which included 15 sites with previous records and 
12 prairie remnants without

[[Page 63739]]

previous records for the species (Service 2014, unpubl. geodatabase.). 
Based on similar conditions in other parts of the species' range, 
similar trends are anticipated outside of Minnesota.
    Indications of recent declining trends have been observed in South 
Dakota and North Dakota. In South Dakota, for example, the proportion 
of positive surveys at known sites has fluctuated over time; however, 
the 2012 and 2013 surveys had the lowest positive detection rate (38 
percent and 32 percent, respectively) for the last 15 years (since 
1996)--much less than comparable survey years in South Dakota (for 
years with more than 20 surveys). The Dakota skipper was detected at 12 
of the 23 sites surveyed during 2012 in North Dakota (and 2 additional 
sites with no previous Dakota skipper records); average encounter 
frequencies observed across the State in 2012 (9.4 encounters per 
hour), however, were about half of those observed during the 1996-1997 
State-wide surveys (ND State average = 17.4 encounters per hour). The 
Dakota skipper was not detected at the three sites that were surveyed 
in 2013 in North Dakota with previous records of the species. Recent 
survey results and similar life histories suggest that the Dakota 
skipper can be reasonably compared to the Poweshiek skipperling in 
their potential rate of decline--that is, it is reasonable to assume 
that Dakota skipper may be vulnerable to the same unidentified factors 
that have caused dramatic declines in the Poweshiek skipperling, with a 
slight delay in timing.
    In summary, the results of extensive surveys in the western portion 
of the Poweshiek skipperling's range have documented the species' 
response to unknown factors and indicate that they are a current 
stressor of high severity. Although to date the Dakota skipper has not 
experienced such dramatic declines as the Poweshiek skipperling, 
similar unknown stressors on Dakota skipper populations likely have 
affected the species in Minnesota and Iowa, where recent surveys 
indicate that the species may be largely absent or at undetectable 
levels.
Summary of Factor E
    Based on our analysis of the best available information, we have 
identified several natural and manmade factors affecting the continued 
existence of the Dakota skipper and Poweshiek skipperling. Effects of 
small population size, population isolation, and loss of genetic 
diversity are likely stressors that have significant impacts on both 
species. Environmental effects resulting from climatic change, 
including increased flooding and drought, are expected to become severe 
in the future and result in additional habitat losses; however, we have 
limited information on how this stressor may affect either species. 
Possibly the stressor with the most significant impacts to the 
Poweshiek skipperling are one or more unknown factors that have led to 
widespread and sharp population declines in the western portion of the 
species' range. These unknown stressors may also be the cause of the 
recent declines observed in Dakota skipper populations over much of its 
range. Anthropogenic factors such as insecticide, herbicide, and 
pesticide use are also stressors to both species, and unregulated 
prairie plant harvest has the potential to become a stressor in the 
future (See Factor E). Collectively, these stressors have operated in 
the past, are impacting both species now, and will continue to impact 
the Dakota skipper and Poweshiek skipperling in the future.
Conservation Efforts To Reduce Other Natural or Manmade Factors 
Affecting Its Continued Existence
    Several of the conservation activities discussed under Factor A. in 
this rule may address some factors discussed under Factor E, for 
example, life-history studies of both species, studies to examine the 
effects of various management strategies on the species and its 
habitat, and habitat restoration techniques such as controlled burns on 
sites divided into several management units.
    The Minnesota Zoo has initiated a new program to research Poweshiek 
skipperling and Dakota skipper propagation. If this program is 
successful, it could facilitate reintroduction and augmentation into 
areas where the species has declined or disappeared, to bolster the 
small genetic pool and small numbers. In 2012, researchers at the 
Minnesota Zoo and the University of Michigan initiated a genetics study 
of Dakota skipper and Poweshiek skipperling using specimens at some of 
the few sites where either species was observed in 2012, specifically a 
few sites in Michigan, Wisconsin, and Manitoba for the Poweshiek 
skipperling and sites in North Dakota, South Dakota, and Manitoba for 
Dakota skipper. Too few (one adult male) Dakota skipper were observed 
in Minnesota to obtain samples from that State in 2012. Similarly, only 
six individuals were observed at one Minnesota site in 2013. The 
genetics studies will help inform captive propagation and 
reintroduction efforts, which may help alleviate stressors associated 
with small and isolated populations.
    In 2011, researchers collected 32 adult Dakota skippers from a 
combination of 4 sites in South Dakota and translocated them to 
Pickerel Lake State Park, where the species was last detected in 2008 
(Skadsen 2011, pp. 7-9). The phenology of the adult flight period and 
purple coneflower blooms did not coincide, and no Dakota skippers were 
observed at the release site during subsequent visits in 2011 or 2012 
(Skadsen 2011, pp. 8-9, Skadsen 2012, p. 4). Researchers and managers 
continue to develop prairie restoration and management goals for this 
and the Hartford Beach State Park site in South Dakota (Skadsen 2011, 
p. 9; Skadsen 2012b, p. 7).
    The Minnesota Zoo has also begun a study to investigate the levels 
of neonicotinoids, aphid pesticides, and other insecticides present at 
several skipper sites in Minnesota and at least one site in South 
Dakota.
    We are unaware of any conservation efforts that directly address 
the impacts of climate change to Dakota skippers or Poweshiek 
skipperlings. We are unaware of any conservation efforts that address 
the possible effects of pharmaceuticals on the Poweshiek skipperling 
and Dakota skipper.

Cumulative Effects From Factors A Through E

    Many of the stressors described in this final rule may cumulatively 
or synergistically impact the Dakota skipper and Poweshiek skipperling 
beyond the scope of each individual stressor. For example, improper 
grazing management alone may only affect portions of Dakota skipper or 
Poweshiek skipperling habitat; however, improper grazing combined with 
invasive plants, herbicide use, and drought may collectively result in 
substantial habitat loss, degradation, or fragmentation across large 
portions of the species' ranges. In turn, climate change may exacerbate 
those effects, further diminishing habitat and increasing the isolation 
of already declining and isolated populations, making them more 
susceptible to genetic drift or catastrophic events such as fire, 
flooding, and drought. Further, nonagricultural development such as 
gravel mining or housing development not only can directly destroy 
habitat, but also can increase fragmentation of habitat by increasing 
associated road development. Additionally, draining prairie fens will 
increase invasive plant and woody vegetation encroachment. Numerous 
stressors are likely acting

[[Page 63740]]

cumulatively to further increase impacts on the already vulnerable, 
small, and isolated populations of Poweshiek skipperling and Dakota 
skipper.

Determination

Dakota Skipper

    We carefully assessed the best scientific and commercial 
information available regarding the past, present, and future threats 
to the Dakota skipper. Dakota skippers are obligate residents of 
undisturbed (remnant, untilled) high-quality prairie, ranging from wet-
mesic tallgrass prairie to dry-mesic mixed-grass prairie. Native 
tallgrass prairies have been reduced by 85 to 99.9 percent of their 
former area, and native mixed-grass prairies have been reduced by 71.9 
to 99 percent of their former area in North Dakota, Manitoba, and 
Saskatchewan. The Dakota skipper was once a common prairie butterfly 
widely dispersed in five States, extending from Illinois to North 
Dakota, and portions of two Canadian provinces. However, its range is 
now substantially reduced such that the Dakota skipper is restricted to 
small patches of fragmented native-prairie remnants in portions of 
three States and two Canadian provinces. Recent survey data indicate 
that the Dakota skipper has declined to zero or to undetectable levels 
in approximately 77 percent of sites where it had been recorded 
rangewide. It is presumed extirpated from Illinois and Iowa and no 
longer occurs in eastern Minnesota.
    Much of the rangewide decline in the species has been observed in 
the last few years. Since 1988, researchers have surveyed 10 or more 
sites in 25 years; the average positive detection rate for those years 
is 63 percent rangewide. Since 2009, the percent of surveyed sites with 
positive detections of the species has dropped from 63 percent in 2009, 
to 41 percent in 2010, 36 percent in 2011, 37 percent in 2012, and 22 
percent in 2013. While these types of lows in detections have been 
observed in past years, for example, in the early 1990s, the numbers of 
individuals observed in 2013 were the lowest ever recorded, despite 
extensive survey effort. Dakota skippers currently occupy sites in 
northeastern South Dakota, North Dakota, western Minnesota, southern 
Manitoba, and southeastern Saskatchewan.
    Of the 264 historical locations, the species is presumed extirpated 
or possibly extirpated from at least 93 (35 percent) of those sites, 
and the occupancy of the species is unknown at approximately 88 (33 
percent) sites. Of the 88 sites where the occupancy is unknown, at 
least 78 sites are subject to one or more stressors that have a 
moderate to high impact on those populations--these sites are 
distributed across Minnesota, North Dakota, and South Dakota. Three 
sites with unknown occupancy were not evaluated for stressors, due to 
lack of information. The 7 sites with unknown occupancy without 
moderate- to high-level stressors are scattered in various counties in 
Minnesota and South Dakota, and the skipper is thought to still be 
present at approximately 83 (31 percent) of the 264 historical 
locations, although 22 of these sites have not been surveyed since 
2002. Of those 83 sites, at least 73 sites are subject to one or more 
stressors that have a moderate to high impact on those populations, 
such as conversion to agriculture, lack of management, and small size 
and isolation. Four sites were not evaluated due to lack of 
information, and the remaining six sites that do not have stressors 
with moderate- to high-level impacts to populations occur in scattered 
counties in Minnesota and South Dakota.
    Approximately half (40 of 83) of the locations where the species is 
considered to be present are primarily located on privately owned fall-
hayed prairies in Canada, mostly within 2 isolated complexes, and have 
not been surveyed since 2007. All 40 of those Canadian sites have one 
or more stressors of moderate to high level of impact to populations. 
Approximately 15 populations in Canada are on lands that are being used 
in ways that are favorable to the Dakota skipper (i.e., late-season 
haying conducted at least every other year and there is no indication 
that native plant species diversity is declining due to timing or 
frequency of mowing), and the stressors at those sites are not 
immediate. However, we are aware of only one of these Canadian 
populations that is protected (on Federal land). The remaining sites 
where the species is considered to be present are about equally 
distributed among Minnesota (11 sites), North Dakota (16 sites), and 
South Dakota (14 sites). Sites with stressors with moderate to high 
level of impacts to populations occur in all three States.
    Many factors likely contributed to the Dakota skipper's decline, 
and numerous factors, acting individually or synergistically, continue 
today (see Summary of Factors Affecting the Species). We identified 
many stressors to the species, some of which rise to the level of 
threats that contribute to the listing status for each species. Habitat 
loss and degradation have impacted the Dakota skipper, curtailing the 
ranges of the species (see Factor A). Extensive historical conversion 
of prairie and associated habitats, nearly complete in some areas, has 
isolated many Dakota skipper populations. These small and isolated 
populations are subject to loss of genetic diversity through genetic 
drift (see Factor E) and are susceptible to a variety of stochastic 
(e.g., wildfires, droughts, and floods) and deterministic (e.g., 
overgrazing, invasive species) factors (see Factor A) that may kill all 
or a substantial proportion of a population.
    Although much of the habitat conversion occurred in the past, the 
effects of the dramatic reduction and fragmentation of habitat have 
persistent and ongoing effects on the viability of populations; 
furthermore, conversion of native prairies to agriculture or other uses 
is still occurring today. The life history of the species exacerbates 
the threats caused by the fragmentation and degradation of the species' 
habitat (see Factors A and E) as the Dakota skipper is not likely to 
recolonize distant sites due to its short adult life span, single 
annual flight, and limited dispersal ability. Therefore, the species' 
extirpation from a site is likely permanent unless it is near another 
site from which it can emigrate. Furthermore, because the larvae are 
located at or near the soil surface, they are more vulnerable to fire 
(Factor A); herbicides, pesticides, and other chemicals (see Factor E); 
desiccation due to changing climate (see Factor E); or flooding (see 
Factor A).
    Within the remaining native-prairie patches, degradation of habitat 
quality is now the primary threat to the Dakota skipper (see Factor A). 
Of the various threats to Dakota skipper habitat, conversion, invasive 
species, secondary succession, and reduction in the diversity of 
native-prairie plant communities have moderate- to high-level impacts 
to populations throughout the range of the Dakota skipper. An array of 
other factors including nonagricultural development, chemical 
contaminants, pesticides, and intensive grazing are also current and 
ongoing threats to the Dakota skipper and its habitat (see Factors A 
and E). Current and ongoing prairie management practices, such as 
indiscriminate use of herbicides or intensive grazing that reduces or 
eliminates food sources, contribute to the species' imperilment at 
sites throughout the range of the species (see Factors A and E).
    Unknown factors may be the current threat that has the most 
significant impacts to the Dakota skipper in Iowa and Minnesota, where 
populations experienced a sudden decline to

[[Page 63741]]

undetectable numbers in the most recent years (see Factor E). Based on 
recent data, similar conditions in other parts of the Dakota skipper's 
range, and the similarities in life histories between Poweshiek 
skipperling and Dakota skipper, similar declining trends are 
anticipated in other parts of the Dakota skipper's range due to unknown 
factors, and may only be a few years behind those declines experienced 
by other species, such as the Poweshiek skipperling (see Factor E). 
Existing regulatory mechanisms vary across the species' ranges, and 
although mechanisms do exist that protect the species from direct take 
in Iowa and Minnesota, these mechanisms do not sufficiently mitigate 
threats to the species (see Factor D). Climate change may affect Dakota 
skipper, especially increased frequency of extreme climatic conditions 
such as flooding and drought, but there is limited information on the 
exact nature of impacts that these species may experience. Recent 
temperature and precipitation trends indicate that certain aspects of 
climate change may be occurring in Dakota skipper range now (see Factor 
E).
    The Act defines an endangered species as any species that is ``in 
danger of extinction throughout all or a significant portion of its 
range'' and a threatened species as any species ``that is likely to 
become endangered throughout all or a significant portion of its range 
within the foreseeable future.'' We find that the Dakota skipper is 
likely to become endangered throughout all of its range within the 
foreseeable future, based on the immediacy, severity, and scope of the 
threats described above. These threats are exacerbated by small 
population sizes, the loss of redundancy and resiliency of these 
species, and the continued inadequacy of existing protective 
regulations. A few scattered populations of Dakota skipper are doing 
relatively well, however, and are in habitats that have low or non-
immediate threats.
    Canada has approximately 15 populations on lands that are being 
utilized in a manner conducive to the conservation of Dakota skipper, 
and the threats at those sites are not imminent. However, few of these 
populations are protected, many are vulnerable to changes in land use, 
landowners may not be aware of the species presence and may change land 
use, and the sites have not been surveyed in the last 5 years. While a 
few new locations of Dakota skipper populations continue to be 
discovered in North and South Dakota, the numbers of individuals 
observed at those sites is generally low, and extirpation at previously 
known sites seems to be occurring at a faster rate than new 
discoveries. The decreasing numbers of sites with positive detections 
and the decreasing numbers of individuals observed at each site 
throughout its range, including known sites in Minnesota, North Dakota, 
and South Dakota, is likely to continue. Therefore, on the basis of the 
best available scientific and commercial information, we are listing 
the Dakota skipper as a threatened species in accordance with sections 
3(20) and 4(a)(1) of the Act.
    We find that an endangered species status is not appropriate for 
the Dakota skipper because some Dakota skipper populations still appear 
to be doing relatively well (populations detected during the last 
survey year, numbers appear stable, lower levels of threats and 
stressors)--primarily in North Dakota, South Dakota, Manitoba, and 
Saskatchewan. About 14 to 15 sites in Manitoba are used in a manner 
conducive to the conservation of Dakota skipper (haying after the adult 
flight period), and the threats at those sites are not imminent. 
Furthermore, we believe the species to be present in at least 6 sites 
that do not have documented stressors of a moderate- to high-level 
impact to populations, primarily in scattered counties in Minnesota and 
South Dakota. Additionally, a few new Dakota skipper sites continue to 
be discovered in suitable prairie habitat in North Dakota and South 
Dakota.
    Under the Act and our implementing regulations, a species may 
warrant listing if it is endangered or threatened throughout all or a 
significant portion of its range. Because we have determined that the 
Dakota skipper is a threatened species throughout all of its range, no 
portion of its range can be ``significant'' for purposes of the 
definitions of ``endangered species'' and ``threatened species.'' See 
the Final Policy on Interpretation of the Phrase ``Significant Portion 
of Its Range'' in the Endangered Species Act's Definitions of 
``Endangered Species'' and ``Threatened Species'' (79 FR 37577).

Poweshiek Skipperling

    We carefully assessed the best scientific and commercial 
information available regarding the past, present, and future threats 
to the Poweshiek skipperling. Poweshiek skipperling are obligate 
residents of undisturbed (remnant, untilled) high-quality prairie, 
ranging from wet-mesic tallgrass prairie to dry-mesic mixed-grass 
prairie. Native tallgrass prairies have been reduced by 85 to 99.9 
percent of their former area, and native mixed-grass prairies have been 
reduced by 72 to 99 percent of their former area in North Dakota, 
Manitoba, and Saskatchewan. The Poweshiek skipperling was once a common 
prairie butterfly widely dispersed in eight States, extended from 
Michigan to North Dakota, and portions of Manitoba, Canada. However, 
its range is now substantially reduced such that the Poweshiek 
skipperling is restricted to small patches of fragmented native-prairie 
remnants in portions of two States and one Canadian province. The 
species is presumed extirpated from Illinois and Indiana, and the 
status of the species is unknown in four of the six States with 
relatively recent records (within the last 20 years). Recent survey 
data indicate that the Poweshiek skipperling has declined to zero or to 
undetectable levels in approximately 96 percent of sites where it has 
ever been recorded.
    A drastic decline in this species has been observed rangewide very 
recently. Between 1985 and 2003, researchers surveyed 10 or more sites 
in 7 different years (excluding new sites in the first year); the 
average positive detection rate for those years is 71 percent 
rangewide. Since 2003, the percent of surveyed sites with positive 
detections of the species has dropped to an average of 31 percent each 
year (2004-2013), with a low of 12 percent at sites surveyed in 2012 
and 2013. Despite recent substantial survey efforts in those States, 
the Poweshiek skipperling has not been recorded in Iowa since 2007, 
when it was observed at 1 site; in North Dakota since 2001, when it was 
observed at 1 site, nor in South Dakota since 2008, when it was 
observed at 3 sites. The species was not observed in North Dakota, 
South Dakota, or Minnesota during 2012 surveys, for example. The 
Poweshiek skipperling was observed at one site in Minnesota in 2007 and 
there was a sighting of a Poweshiek skipperling at one site in 2013, 
although no photographs or specimens were taken to confirm the 
sighting. Iowa sites were not surveyed in 2012, and the species was not 
detected in 2013. Poweshiek skipperling have historically been 
documented at approximately 296 sites; now we consider the species to 
be present at only 12 of those sites--one of these is considered a sub-
site of a larger site.
    The only confirmed extant (present) populations of Poweshiek 
skipperling are currently restricted to 1 small and isolated native-
prairie remnant in Wisconsin, 9 small and isolated prairie fen remnants 
in Michigan, and a prairie complex in Manitoba. The species may also be 
present at one site in Minnesota. These sites represent less than 5 
percent of the total number of sites ever

[[Page 63742]]

documented for the species. The numbers observed at these sites are 
relatively small (fewer than 100 individuals at all sites surveyed in 
2013), and all of these sites have at least one documented threat that 
has moderate to high impacts on those populations. The strongest 
population in the United States, a prairie fen in Michigan with 
relatively high and fairly consistent numbers observed each year 
(numbers observed per minute ranged from 0.2 to 2.2 during the last 6 
survey years), for instance, is under threat from intense development 
pressure. The Tallgrass Prairie Preserve site in Manitoba also has 
relatively high numbers observed each year; however, this site is 
impacted by several immediate, moderate- to high-level threats, 
including the encroachment of invasive plants and woody vegetation, 
flooding, and isolation from the nearest site by hundreds of 
kilometers. In addition, recent unplanned fires in 2009 and 2011 
affected large portions of the site. Poweshiek skipperling is 
considered to have unknown occupancy at 75 sites--throughout the range 
of the species (Iowa, Michigan, Minnesota, North Dakota, and South 
Dakota), 49 of these sites were included in the threats assessment. Of 
the 49 sites where the occupancy is unknown that had sufficient 
information to assess, at least 42 sites are subject to one or more 
threats that have a moderate to high impact on those populations. These 
sites are throughout the range of the species in Iowa, Michigan, 
Minnesota, North Dakota, and South Dakota.
    Many factors likely contributed to the Poweshiek skipperling's 
decline, and numerous major threats, acting individually or 
synergistically, continue today (see Summary of Factors Affecting the 
Species). Habitat loss and degradation have impacted the Poweshiek 
skipperling, curtailing the ranges of both species (see Factor A). 
Extensive historical conversion of prairie and associated habitats, 
nearly complete in some areas, has isolated many Poweshiek skipperling 
populations. These small and isolated populations are subject to loss 
of genetic diversity through genetic drift (see Factor E) and are 
susceptible to a variety of stochastic (e.g., wildfires, droughts, and 
floods) and deterministic (e.g., overgrazing, invasive species) factors 
(see Factor A) that may kill all or a substantial proportion of a 
population. Although much of the habitat conversion occurred in the 
past, the effects of the dramatic reduction and fragmentation of 
habitat have persistent and ongoing effects on the viability of 
populations; furthermore, conversion of native prairies to agriculture 
or other uses is still occurring today. The life history of the species 
exacerbates the threats caused by the fragmentation and degradation of 
its habitat (see Factors A and E) as Poweshiek skipperlings are not 
likely to recolonize distant sites due to their short adult life span, 
single annual flight, and limited dispersal ability. Therefore, the 
Poweshiek skipperling's extirpation from a site is likely permanent 
unless it is near another site from which it can emigrate. Furthermore, 
because the larvae are located at or near the soil surface, they are 
more vulnerable to fire (Factor A), herbicides, pesticides, and other 
chemicals (see Factor E); desiccation due to changing climate (see 
Factor E); or changes in hydrology (see Factor A).
    Within the remaining native-prairie patches, degradation of habitat 
quality is now the primary threat to the Poweshiek skipperling (see 
Factor A). Of the various threats to Poweshiek skipperling habitat, 
conversion, invasive species, secondary succession, and reduction in 
the diversity of native-prairie plant communities have moderate- to 
high-level impacts to populations throughout the range of the Poweshiek 
skipperling. An array of other factors including nonagricultural 
development, chemical contaminants, pesticides, and intensive grazing 
are also current and ongoing threats to the Poweshiek skipperling and 
its habitat (see Factors A and E). Current and ongoing prairie 
management practices, such as indiscriminate use of herbicides or 
intensive grazing that reduces or eliminates food sources, contribute 
to the species' imperilment, particularly in North Dakota, South 
Dakota, and Minnesota (see Factors A and E). Unknown factors may be the 
current threat that has the most significant impacts to the Poweshiek 
skipperling species in Iowa, Minnesota, North Dakota, and South Dakota, 
where populations experienced a sudden decline to undetectable numbers 
in the most recent years (see Factor E). Existing regulatory mechanisms 
vary across the species' ranges, and although mechanisms do exist in 
Iowa, Michigan, Minnesota, and Wisconsin that protect the species from 
direct take, these mechanisms do not sufficiently mitigate threats to 
the Poweshiek skipperling (see Factor D). Climate change may affect the 
Poweshiek skipperling, especially increased frequency of extreme 
climatic conditions such as flooding and drought, but there is limited 
information on the exact nature of impacts that the species may 
experience. Recent temperature and precipitation trends indicate that 
certain aspects of climate change may be occurring in Poweshiek 
skipperling range now (see Factor E).
    The Act defines an endangered species as any species that is ``in 
danger of extinction throughout all or a significant portion of its 
range'' and a threatened species as any species ``that is likely to 
become endangered throughout all or a significant portion of its range 
within the foreseeable future.'' We find that the Poweshiek skipperling 
is presently in danger of extinction throughout its entire range, based 
on the immediacy, severity, and scope of the threats described above. 
These threats are exacerbated by small population sizes, the loss of 
redundancy and resiliency of these species, and the continued 
inadequacy of existing protective regulations. There are only 12 
locations where we believe the species to be present, and all of those 
sites are subject to at least one or more ongoing and immediate threats 
that have moderate- to high-level effects on those populations. 
Therefore, on the basis of the best available scientific and commercial 
information, we are listing the Poweshiek skipperling as endangered in 
accordance with sections 3(6) and 4(a)(1) of the Act.
    We find that a threatened species status is not appropriate for the 
Poweshiek skipperling because the unknown factors have significant 
impacts to the species throughout most of its range and have occurred 
in a short timeframe. Sharp population declines have not been detected 
at the few remaining sites where the species is still present, but all 
of these sites are currently experiencing one or more threats that have 
moderate- to high-level impacts to populations. Based on recent data 
and similar conditions in other parts of Poweshiek skipperling range, 
similar declining trends are anticipated in other parts of the range of 
the species, and may only be a few years behind those declines 
experienced by the species in Iowa, Minnesota, North Dakota, and South 
Dakota (see Factor E). The impacts of the unknown factors on 
populations are exacerbated by habitat curtailment and destruction and 
other factors such as the effects of small and isolated populations due 
to habitat fragmentation.
    Under the Act and our implementing regulations, a species may 
warrant listing if it is endangered or threatened throughout all or a 
significant portion of its range. Because we have determined that the 
Poweshiek skipperling is an endangered species throughout all of its 
range, no portion of its range can be

[[Page 63743]]

``significant'' for purposes of the definitions of ``endangered 
species'' and ``threatened species.'' See the Final Policy on 
Interpretation of the Phrase ``Significant Portion of Its Range'' in 
the Endangered Species Act's Definitions of ``Endangered Species'' and 
``Threatened Species'' (79 FR 37577).

Available Conservation Measures

    Conservation measures provided to species listed as endangered or 
threatened under the Act include recognition, recovery actions, 
requirements for Federal protection, and prohibitions against certain 
practices. Recognition through listing results in public awareness and 
conservation by Federal, State, Tribal, and local agencies, private 
organizations, and individuals. The Act encourages cooperation with the 
States and requires that recovery actions be carried out for all listed 
species. The protection required by Federal agencies and the 
prohibitions against certain activities are discussed, in part, below.
    The primary purpose of the Act is the conservation of endangered 
and threatened species and the ecosystems upon which they depend. The 
ultimate goal of such conservation efforts is the recovery of these 
listed species, so that they no longer need the protective measures of 
the Act. Subsection 4(f) of the Act requires the Service to develop and 
implement recovery plans for the conservation of endangered and 
threatened species. The recovery planning process involves the 
identification of actions that are necessary to halt or reverse the 
species' decline by addressing the threats to its survival and 
recovery. The goal of this process is to restore listed species to a 
point where they are secure, self-sustaining, and functioning 
components of their ecosystems.
    Recovery planning includes the development of a recovery outline 
shortly after a species is listed, preparation of a draft and final 
recovery plan, and revisions to the plan as significant new information 
becomes available. The recovery outline guides the immediate 
implementation of urgent recovery actions and describes the process to 
be used to develop a recovery plan. The recovery plan identifies site-
specific management actions that will achieve recovery of the species, 
measurable criteria that determine when a species may be downlisted or 
delisted, and methods for monitoring recovery progress. Recovery plans 
also establish a framework for agencies to coordinate their recovery 
efforts and provide estimates of the cost of implementing recovery 
tasks. Recovery teams (comprising species experts, Federal and State 
agencies, nongovernmental organizations, and stakeholders) are often 
established to develop recovery plans. When completed, the recovery 
outlines, draft recovery plans, and the final recovery plans will be 
available on our Web site (http://www.fws.gov/endangered), or from our 
Twin Cities Ecological Services Fish and Wildlife Office (see FOR 
FURTHER INFORMATION CONTACT).
    Implementation of recovery actions generally requires the 
participation of a broad range of partners, including other Federal 
agencies, States, Tribes, nongovernmental organizations, businesses, 
and private landowners. Examples of recovery actions include habitat 
restoration (e.g., restoration of native vegetation), research, captive 
propagation and reintroduction, and outreach and education. The 
recovery of many listed species cannot be accomplished solely on 
Federal lands because their range may occur primarily or solely on non-
Federal lands. To achieve recovery of these species requires 
cooperative conservation efforts on private, State, and Tribal lands.
    When species are listed, funding for recovery actions will be 
available from a variety of sources, including Federal budgets, State 
programs, and cost-share grants for non-Federal landowners, the 
academic community, and nongovernmental organizations. In addition, 
pursuant to section 6 of the Act, the States of Iowa, Michigan, 
Minnesota, North Dakota, South Dakota, and Wisconsin would be eligible 
for Federal funds to implement management actions that promote the 
protection and recovery of the Poweshiek skipperling and Dakota 
skipper. Information on our grant programs that are available to aid 
species recovery can be found at: http://www.fws.gov/grants.
    Please let us know if you are interested in participating in 
recovery efforts for the Dakota skipper or Poweshiek skipperling. 
Additionally, we invite you to submit any new information on these 
species whenever it becomes available and any information you may have 
for recovery planning purposes (see FOR FURTHER INFORMATION CONTACT).
    Section 7(a) of the Act requires Federal agencies to evaluate their 
actions with respect to any species that is proposed or listed as 
endangered or threatened and with respect to its critical habitat, if 
any is designated. Regulations implementing this interagency 
cooperation provision of the Act are codified at 50 CFR part 402. If a 
species is listed subsequently, section 7(a)(2) of the Act requires 
Federal agencies to ensure that activities they authorize, fund, or 
carry out are not likely to jeopardize the continued existence of the 
species or destroy or adversely modify its critical habitat. If a 
Federal action may adversely affect a listed species or its critical 
habitat, the responsible Federal agency must enter into formal 
consultation with the Service.
    Federal agency actions within the species habitat that may require 
conference or consultation or both as described in the preceding 
paragraph include, but are not limited to, management and any other 
landscape-altering activities on Federal lands such as actions within 
the jurisdiction of the NRCS; land management by the U.S. Forest 
Service; issuance of section 404 Clean Water Act permits by the U.S. 
Army Corps of Engineers; land management by the U.S. Fish and Wildlife 
Service; construction and management of gas pipeline, wind facilities 
and associated infrastructure, and power line rights-of-way by the 
Federal Energy Regulatory Commission; construction and maintenance of 
roads or highways by the Federal Highway Administration; and land 
management within branches of the Department of Defense (DOD). Examples 
of these types of actions include activities funded or authorized under 
the Farm Bill Program, Environmental Quality Incentives Program, Clean 
Water Act (33 U.S.C. 1251 et seq.), Partners for Fish and Wildlife 
Program, and DOD construction activities related to training or other 
military missions.

Poweshiek Skipperling

    The Act and its implementing regulations set forth a series of 
general prohibitions and exceptions that apply to all endangered 
wildlife. The prohibitions of section 9(a)(2) of the Act, codified at 
50 CFR 17.21 for endangered wildlife, in part, make it illegal for any 
person subject to the jurisdiction of the United States to take 
(includes harass, harm, pursue, hunt, shoot, wound, kill, trap, 
capture, or collect; or to attempt any of these), import, export, ship 
in interstate commerce in the course of commercial activity, or sell or 
offer for sale in interstate or foreign commerce any listed species. 
Under the Lacey Act (18 U.S.C. 42-43; 16 U.S.C. 3371-3378), it is also 
illegal to possess, sell, deliver, carry, transport, or ship any such 
wildlife that has been taken illegally. Certain exceptions apply to 
agents of the Service and State conservation agencies.

[[Page 63744]]

Dakota Skipper

    Under section 4(d) of the Act, the Service has discretion to issue 
regulations that we find necessary and advisable to provide for the 
conservation of threatened wildlife. We may also prohibit by regulation 
with respect to threatened wildlife any act prohibited by section 
9(a)(1) of the Act for endangered wildlife. Exercising this discretion, 
the Service has developed a 4(d) rule containing all the general 
prohibitions and exceptions to those prohibitions; these are found at 
50 CFR 17.31 and 50 CFR 17.32. For the Dakota skipper, the Service has 
developed a 4(d) rule that is tailored to the specific threats and 
conservation needs of this species. As a means to promote conservation 
efforts on behalf of the Dakota skipper, we are finalizing a 4(d) rule 
for this species that modifies the standard protections for threatened 
wildlife found at 50 CFR 17.31. In the case of a 4(d) rule, the general 
regulations (50 CFR 17.31 and 17.71) applying most prohibitions under 
section 9 of the Act to threatened species do not apply to that 
species, and the 4(d) rule contains the prohibitions necessary and 
advisable to conserve that species.
    As discussed above, the primary factors supporting the 
determination of threatened species status for the Dakota skipper are 
habitat loss and degradation of native prairies, including conversion 
of native prairie for agriculture or other development; ecological 
succession and encroachment of invasive species and woody vegetation; 
certain fire, haying, and grazing management that reduces the 
availability of certain native-prairie grasses and flowering herbaceous 
plants to the Dakota skipper; some fire management; flooding; existing 
regulatory mechanisms that are inadequate to mitigate threats to the 
species; loss of genetic diversity; small size and isolation of remnant 
patches of native prairie; indiscriminate use of herbicides that 
reduces or eliminates nectar sources; climate conditions such as 
drought; and other unknown factors.
    The Act does not specify particular prohibitions, or exceptions to 
those prohibitions, for threatened species. Instead, under section 4(d) 
of the Act, the Secretary of the Interior has the discretion to issue 
such regulations as she deems necessary and advisable to provide for 
the conservation of such species. The Secretary also has the discretion 
to prohibit by regulation with respect to any threatened species, any 
act prohibited under section 9(a)(1) of the Act. Exercising this 
discretion, the Service has developed general prohibitions (50 CFR 
17.31) and exceptions to those prohibitions (50 CFR 17.32) under the 
Act that apply to most threatened species. Alternately, for other 
threatened species, the Service develops specific prohibitions and 
exceptions that are tailored to the specific conservation needs of the 
species. In such cases, some of the prohibitions and authorizations 
under 50 CFR 17.31 and 17.32 may be appropriate for the species and 
incorporated into a rule under section 4(d) of the Act, but the section 
4(d) rule will also include provisions that are tailored to the 
specific conservation needs of the threatened species and may be more 
or less restrictive than the general provisions at 50 CFR 17.31.
    In recognition of efforts that provide for conservation and 
management of the Dakota skipper and its habitat in a manner consistent 
with the purposes of the Act, this 4(d) rule outlines the prohibitions, 
and exceptions to those prohibitions, necessary and advisable for the 
conservation of the Dakota skipper.
    Conversion of grasslands for the production of agricultural crops 
poses a threat to the Dakota skipper because it may directly destroy 
the species' habitat, increase isolation of populations by impeding 
dispersal, and increase the risk posed by drift of herbicides and 
pesticides. A wide variety of peer-reviewed publications and government 
reports have documented recent conversion of native grassland. In 
addition, economic and policy incentives are likely to continue to 
place pressure on landowners to convert native grassland from ranching 
to agricultural cropland (Doherty et al. 2013, p. 14); Sylvester et al. 
2013, p. 13; Rashford et al. 2011, p. 282; Stephens et al. 2008, p. 6; 
(Congressional Research Service (CRS) 2007, p. 5, United States 
Government Accountability Office (USGAO) 2007, p. 15, Stephens et al. 
2008, p. 6, Rashford et al. 2011, p. 282, Sylvester et al. 2013, p. 
13). Grassland loss in the western corn belt may be occurring at the 
fastest rate observed since the 1920s and 1930s and at a rate 
comparable to that of deforestation in Brazil, Malaysia, and Indonesia 
(Wright and Wimberly 2013, p. 5). Between 2006 and 2011, destruction of 
native grassland was mostly concentrated in North Dakota and South 
Dakota, east of the Missouri River, an area corresponding closely to 
the range of the Dakota skipper (Wright and Wimberly 2013, p. 2). In 
northeastern South Dakota, one of the few remaining strongholds for the 
Dakota skipper, about 269,000 acres (108,907 ha) of grassland was 
lost--primarily to cropland--between 2006 and 2012 (Reitsma et al. 
2014, p. 3).
    As with agricultural policies (Doherty et al. 2013, p. 15), 
prohibitions against take of Dakota skippers could interact with other 
factors to affect the rates at which native grassland is converted in 
the range of the species. Less than 20 percent of the grassland in the 
Prairie Pothole Region of the United States is permanently protected 
(Doherty et al. 2013, p. 7), and the vast majority of remaining 
grassland is privately owned. The conservation of ``working 
landscapes'' based on ranching and livestock operations (`grass-based 
farming') is frequently a priority of programs to conserve native 
grassland ecosystems in the northern Great Plains (e.g., U.S. Fish and 
Wildlife Service 2011, p. 5). Exempting incidental take of Dakota 
skippers that may result from grazing and other routine livestock 
ranching activities will afford us more time to protect the species' 
habitats in these areas and will facilitate the cooperation and 
partnerships with livestock producers necessary to recover the species.
    Three primary factors have led us to determine that it is necessary 
and advisable to exempt take of Dakota skippers caused by certain 
ranching activities, including grazing. First, a variety of 
socioeconomic and policy factors are leading to the conversion of 
native grasslands for the production of agricultural crops, as 
summarized above. Whereas conversion of native grassland for crop 
production would result in a permanent loss of Dakota skipper habitat 
and may also exacerbate other threats (e.g., pesticide drift) to the 
species, grasslands can remain suitable for Dakota skippers when grazed 
(see below and Dana 1991, p. 54; Schlicht 1997, p. 5; Skadsen 1997, pp. 
24-29). By exempting take of Dakota skippers caused by grazing, we 
acknowledge the positive role that some ranchers have already played in 
conserving Dakota skippers and the importance of preventing any 
additional loss and fragmentation of native grasslands as the result of 
activities in areas that could support the species.
    Second, although some grazing practices pose a threat to Dakota 
skipper, grazing may also be an effective tool to improve Dakota 
skipper habitat when carefully applied in cooperation and consultation 
with private landowners, public land managers, and grazing experts. In 
eastern South Dakota, Dakota skipper populations were deemed secure at 
some sites managed with rotational grazing that was sufficiently light 
to maintain native plant species diversity (Skadsen 1997,

[[Page 63745]]

pp. 24-29), and grazing may also benefit Dakota skippers by increasing 
coverage of mid-height grasses, such as little bluestem, relative to 
tallgrasses, such as big bluestem and Indiangrass (Dana 1991, p. 54). 
Intensive early-season grazing can reduce the extent of Kentucky 
bluegrass, a nonnative species that invades prairie habitats and 
competes with native plant species (DeKeyser et al. 2013, p. 86). In 
addition, grazing may also inhibit the establishment of smooth brome 
and help to enhance coverage and diversity of native plants in prairies 
that have been invaded by nonnative cool-season grasses (U.S. Fish and 
Wildlife Service 2006, p. 2; DeKeyser et al. 2009, p. 18; Smart et al. 
2013, p. 686). Because grazing can lead to adverse conditions for the 
Dakota skipper, however, the Service encourages collaboration with 
private landowners, public land managers (e.g., Skadsen 2006, p. 5), 
State and Federal conservation agencies, and nongovernmental 
organizations to identify, implement, monitor, and refine grazing 
practices that are conducive to the species' conservation.
    Third, recovery of the Dakota skipper will depend on the protection 
and restoration of high-quality habitats for the species on private 
lands and on public lands that are grazed or hayed by private 
individuals under lease or other agreements. Conservation of Dakota 
skippers on these lands will require the development and implementation 
of complex, individualized, and long-term management agreements that 
rely on robust monitoring of Dakota skipper populations and habitat 
features. All of these agreements will require a willingness on the 
part of the private ranchers to collaborate with the Service and our 
partners to implement, monitor, and adapt conservation grazing 
practices in a manner that allows for stable or growing Dakota skipper 
populations. This type of cooperative approach is more likely to take 
place and to be successful if we exempt take caused by grazing and the 
other activities that we specify in the 4(d) rule.
    In some geographic areas, such as McHenry County, North Dakota, the 
Dakota skipper almost exclusively inhabits relatively flat and moist 
prairie habitats that are mowed for hay. In these areas we do not 
encourage a switch to grazing without careful consideration of the 
potential consequences to the Dakota skipper. These habitats, referred 
to as calcareous or ``alkaline prairies'' by McCabe (1979, p. 17; 1981, 
p. 179); ``wet mesic'' by Royer and Marrone (1992, p. 21); and ``Type 
A'' by Royer et al. (2008, p. 14), are distinguished from other Dakota 
skipper habitats by relatively flat topography and certain plant 
community and soil characteristics (Lenz 1999, pp. 5-7; Royer et al. 
2008, pp. 14-15). Dakota skippers appear to be generally absent from 
this type of habitat in North Dakota where it is grazed, due to a shift 
away from a plant community that is suitable for the species (McCabe 
1979, p. 17; 1981, p. 179). The shift in plant community composition 
and adverse effects to Dakota skipper populations may occur rapidly 
(McCabe 1981, p. 179; Royer and Royer 1998, p. 23). The conversion of 
similar habitats in Manitoba from haying to grazing may be a major 
threat to the Dakota skipper there as well (Webster 2007, pp. i-ii, 6). 
In contrast, limited or ``light rotational grazing'' of habitats on 
steep dry-mesic slopes in Saskatchewan may not conflict with Dakota 
skipper conservation (Webster 2007, p. ii).
    The reduced vulnerability of habitats on dry-mesic slopes to the 
effects of grazing may be due, in part, to the tendency for grazing 
pressure to be lighter in sloped areas. The steepness of habitats 
occupied by Dakota skippers in Saskatchewan, for example, limits their 
use for grazing (Webster 2007, p. ii). Steep slopes may also play a 
role in reducing the adverse effects of grazing at some sites in South 
Dakota--at one grazed site inhabited by the Dakota skipper, for 
example, habitat on steep slopes was ``in good condition,'' whereas 
``lesser slopes'' were ``moderately grazed'' and some areas were 
``overgrazed'' (Skadsen 1999a, p. 29).
    In the proposed rule, we cited the lack of any examples of strong 
populations of Dakota skippers where the relatively moist and flat 
(`Type A') habitats are grazed as evidence that it would not be 
necessary and advisable to exempt take caused by grazing in certain 
counties where `Type A' habitats are found. As stated above, we still 
do not recommend a change to grazing on `Type A' habitats occupied by 
the Dakota skipper unless a cooperative plan is developed to ensure 
that it will be done in a manner that conserves the species in the 
affected habitats. Nevertheless, in light of the great importance that 
cooperative relationships with certain public land management agencies 
and private livestock producers will play in conserving the Dakota 
skipper, we find that it is necessary and advisable to exempt take that 
may be caused by grazing on non-Federal lands regardless of geographic 
area. We do not expect this to result in a significant change in 
management from haying to grazing because other factors, such as the 
costs of building fences and developing livestock watering facilities, 
are more important factors that will influence this land management 
decision.

Provisions of the 4(d) Rule for the Dakota Skipper

    Section 4(d) of the Act states that ``the Secretary shall issue 
such regulations as [s]he deems necessary and advisable to provide for 
the conservation'' of species listed as a threatened species. 
Conservation is defined in the Act to mean ``to use and the use of all 
methods and procedures which are necessary to bring any endangered 
species or threatened species to the point at which the measures 
provided pursuant to [the Act] are no longer necessary.'' Additionally, 
section 4(d) states that the Secretary ``may by regulation prohibit 
with respect to any threatened species any act prohibited under section 
9(a)(1).''
    The courts have recognized the extent of the Secretary's discretion 
under this standard to develop rules that are appropriate for the 
conservation of a species. For example, the Secretary may find that it 
is necessary and advisable not to include a taking prohibition, or to 
include a limited taking prohibition. See Alsea Valley Alliance v. 
Lautenbacher, 2007 U.S. Dist. Lexis 60203 (D. Or. 2007); Washington 
Environmental Council v. National Marine Fisheries Service, and 2002 
U.S. Dist. Lexis 5432 (W.D. Wash. 2002). In addition, as affirmed in 
State of Louisiana v. Verity, 853 F.2d 322 (5th Cir. 1988), the rule 
need not address all the threats to the species. As noted by Congress 
when the Act was initially enacted, ``once an animal is on the 
threatened list, the Secretary has an almost infinite number of options 
available to him with regard to the permitted activities for those 
species. [S]he may, for example, permit taking, but not importation of 
such species,'' or [s]he may choose to forbid both taking and 
importation but allow the transportation of such species, as long as 
the measures will ``serve to conserve, protect, or restore the species 
concerned in accordance with the purposes of the Act'' (H.R. Rep. No. 
412, 93rd Cong., 1st Sess. 1973).
    Section 9 prohibitions make it illegal for any person subject to 
the jurisdiction of the United States to take (including harass, harm, 
pursue, shoot, wound, kill, trap, capture, or collect; or attempt any 
of these), import or export, ship in interstate commerce in the course 
of commercial activity, or sell or offer for sale in interstate or 
foreign commerce any wildlife species listed as an endangered species, 
without written authorization. It also is illegal under

[[Page 63746]]

section 9(a)(1) of the Act to possess, sell, deliver, carry, transport, 
or ship any such wildlife that is taken illegally. Prohibited actions 
consistent with section 9 of the Act are outlined for threatened 
species in 50 CFR 17.31(a) and (b). Through this 4(d) rule, all 
prohibitions in 50 CFR 17.31(a) and (b) apply to the Dakota skipper 
except in the specific instances as outlined below. The 4(d) rule will 
not remove or alter in any way the consultation requirements under 
section 7 of the Act.

Routine Livestock Operations and Maintenance of Recreational Trails and 
Rights-of-Way

    Incidental take that is caused by the routine livestock ranching 
and other specified trail and rights-of-way maintenance activities 
described below and that are implemented on private, State, and tribal 
lands and on other lands not under Federal jurisdiction (e.g. lands 
owned by county governments or local governments) will not be 
prohibited, as long as those activities are otherwise legal and 
conducted in accordance with applicable State, Federal, tribal, and 
local laws and regulations. For the purposes of this 4(d) rule, routine 
livestock ranching and recreational trail and rights-of-way maintenance 
activities include the items listed below. Except as explicitly stated 
below, these activities must be associated with livestock ranching for 
this 4(d) rule to apply.
    (1) Fence Construction and Maintenance: Fences are an essential 
tool for livestock and ranch management. In addition, the strategic 
distribution of fencing is also necessary to implement multi-cell 
rotational grazing systems, which may be necessary to improve grazing 
management and provide a conservation benefit to Dakota skipper 
habitat.
    (2) Livestock Gathering and Management: The installation and 
maintenance of corrals, loading chutes, and other livestock working 
facilities are critical to ranch operations. These activities may be 
carried out with only minimal impacts to Dakota skipper if carefully 
sited with respect to the location and distribution of important Dakota 
skipper habitat.
    (3) Development and Maintenance of Livestock Watering Facilities: 
Without a suitable water source in a pasture, livestock ranching is 
impossible. The proper distribution of livestock watering sources is 
also a prerequisite to implementing improved grazing management via the 
use of multi-cell rotational grazing systems that may be necessary to 
conserve Dakota skipper habitat and to provide a conservation benefit 
to the species on grazed sites. This activity includes both the initial 
development of water sources and their maintenance. Dugout ponds, for 
example, typically require a cleanout after 15 to 20 years.
    (4) Noxious Weed Control: State and county laws require landowners 
to control noxious weeds on their property, and the timing of control 
actions is usually dependent on the growth stage of the weed species. 
Control of noxious weeds may also be important to protect Dakota 
skipper habitat because native plant diversity declines when nonnative 
plant species invade and become established in prairies (Boettcher et 
al. 1993, p. 35). Broadcast application of herbicides, however, may 
result in significant deterioration of native plant diversity in 
prairies (Smart et al. 2011, p. 184). Therefore, incidental take of 
Dakota skipper that may result from spraying of herbicides would be 
exempt except as a result of broadcast spraying, which we define as the 
application of herbicides evenly across the entire application area. 
Note that herbicide applications would not affect the Dakota skipper if 
they do not affect the limited areas where the species is present. 
Broadcast applications of herbicides that do not affect habitats 
occupied by the Dakota skipper would not result in take of the species, 
and thus would not result in violation of section 9 of the Act. Take 
that may occur as a result of mowing that is carried out for the 
purpose of controlling one or more noxious weed species is also 
exempted from the take prohibitions under section 9 of the Act by 
issuance of this 4(d) rule.
    (5) Haying: Stock cows need to be maintained through the non-
growing season though supplemental feeding with hay; thus, haying 
(cutting grass and other vegetation for drying and use as livestock 
feed) is a critical component of ranch activity. Dakota skippers occur 
on several native hayland sites--sites where the native-prairie 
vegetation is mowed for hay. For the purposes of this rule, native 
hayland does not include lands that had previously been plowed and were 
then replanted to native or nonnative vegetation. Native hayland may 
include, however, areas within transportation (e.g., road, highway, 
railroad) rights-of-ways and corridors where native grassland is mowed 
for hay. Native haylands are typically cut in August, after the 
needlegrass (Hesperostipa spp. or Nassella viridula, or both) awns 
drop. Incidental take of Dakota skippers that occurs as a result of 
haying no earlier than July 16 (after July 15) is exempted from the 
take prohibitions under section 9 of the Act by issuance of this 4(d) 
rule. Dakota skippers are unlikely to occur in replanted grasslands 
(grasslands replanted on formerly plowed or cultivated lands) or in 
tame hayland or grassland (hayland or grassland planted to and 
comprising primarily nonnative grass species, such as smooth brome 
(Bromus inermis inermis)). Therefore, mowing replanted and tame 
grasslands before July 16 would not result in take of Dakota skippers 
and would thus not result in a violation of section 9 of the Act.
    (6) Mowing Section Line Rights-of-Way and Recreational Trails: 
Section line rights-of-way and some recreational trails need to be 
mowed several times during the growing season to ensure that snow will 
not catch and block vehicle access and that they are suitable for 
hiking and other intended recreational activities, respectively. 
Section line rights-of-way typically comprise disturbed soil that has 
been contoured for a roadway and are likely to contain only small 
proportions of Dakota skipper habitat at any affected site. Therefore, 
impacts to Dakota skipper populations are likely to be minimal, and any 
incidental take that is a result of mowing of section line rights-of-
way and recreational trails will be exempt from the take prohibitions 
of section 9 of the Act. Recreational trails are travel ways 
established either through construction or use that are intended for 
and passable by at least one or more of the following: foot traffic, 
bicycles, in-line skates, wheelchairs, or cross-country skis. 
Incidental take that may be caused by mowing recreational trails does 
not need to be associated with livestock ranching for the 4(d) rule to 
apply.
    (7) Livestock (Cattle, Bison, or Horse) Grazing: Incidental take of 
Dakota skippers that may result from grazing on private, State, or 
tribal land is exempt from the take prohibitions of section 9 of the 
Act.
    We may issue permits to carry out otherwise prohibited activities 
involving endangered and threatened wildlife species under certain 
circumstances. Regulations governing permits are codified at 50 CFR 
17.22 for endangered species, and at 17.32 for threatened species. With 
regard to endangered wildlife, a permit must be issued for the 
following purposes: For scientific purposes, to enhance the propagation 
or survival of the species, and for incidental take in connection with 
otherwise lawful activities.
    It is our policy, as published in the Federal Register on July 1, 
1994 (59 FR 34272), to identify to the maximum

[[Page 63747]]

extent practicable at the time a species is listed, those activities 
that would or would not constitute a violation of section 9 of the Act. 
The intent of this policy is to increase public awareness of the effect 
of a final listing on proposed and ongoing activities within the range 
of a listed species. Based on the best available information, the 
following actions are unlikely to result in a violation of section 9, 
if these activities are carried out in accordance with existing 
regulations and permit requirements; this list is not comprehensive:
    (1) Unauthorized collecting, handling, possessing, selling, 
delivering, carrying, or transporting of the species, including import 
or export across State lines and international boundaries, except for 
properly documented antique specimens of these taxa at least 100 years 
old, as defined by section 10(h)(1) of the Act;
    (2) Unauthorized modification, removal, or destruction of the 
prairie vegetation, soils, or hydrology in which the Dakota skipper and 
Poweshiek skipperling are known to occur;
    (3) The unauthorized release of biological control agents that 
attack any life stage of these species, including the unauthorized use 
of herbicides, pesticides, or other chemicals in habitats in which the 
Poweshiek skipperling or Dakota skipper is known to occur;
    (4) Introduction of nonnative species that compete with or prey 
upon the Dakota skipper and Poweshiek skipperling or their food 
sources, such as the introduction of nonnative leafy spurge, reed 
canary grass, or glossy buckthorn, to the State of Iowa, Michigan, 
Minnesota, North Dakota, South Dakota, and Wisconsin; and
    (5) Unauthorized discharge of chemicals or fill material into any 
wetlands in which the Poweshiek skipperling or Dakota skipper are known 
to occur.
    Questions regarding whether specific activities would constitute a 
violation of section 9 of the Act should be directed to the Twin Cities 
Ecological Services Fish and Wildlife Office (see FOR FURTHER 
INFORMATION CONTACT). Requests for copies of the regulations concerning 
listed animals and general inquiries regarding prohibitions and permits 
may be addressed to the U.S. Fish and Wildlife Service, Endangered 
Species Permits, 5600 American Blvd., West, Suite 990, Bloomington, MN 
(telephone 612-713-5350; facsimile 612-713-5292).

Required Determinations

National Environmental Policy Act (42 U.S.C. 4321 et seq.)

    We have determined that environmental assessments and environmental 
impact statements, as defined under the authority of the National 
Environmental Policy Act (NEPA; 42 U.S.C. 4321 et seq.), need not be 
prepared in connection with listing a species as an endangered or 
threatened species under the Endangered Species Act. We published a 
notice outlining our reasons for this determination in the Federal 
Register on October 25, 1983 (48 FR 49244).

Government-to-Government Relationship With Tribes

    In accordance with the President's memorandum of April 29, 1994 
(Government-to-Government Relations with Native American Tribal 
Governments; 59 FR 22951), Executive Order 13175 (Consultation and 
Coordination With Indian Tribal Governments), and the Department of the 
Interior's manual at 512 DM 2, we readily acknowledge our 
responsibility to communicate meaningfully with recognized Federal 
Tribes on a government-to-government basis. In accordance with 
Secretarial Order 3206 of June 5, 1997 (American Indian Tribal Rights, 
Federal-Tribal Trust Responsibilities, and the Endangered Species Act), 
we readily acknowledge our responsibilities to work directly with 
tribes in developing programs for healthy ecosystems, to acknowledge 
that tribal lands are not subject to the same controls as Federal 
public lands, to remain sensitive to Indian culture, and to make 
information available to tribes.
    The Sisseton-Wahpeton Oyate, Flandreau Santee Sioux Tribe, Turtle 
Mountain Band of Chippewa, Three Affiliated Tribes, Spirit Lake Sioux 
Tribe, and Standing Rock Sioux Tribe are the main Tribes affected by 
this final rule. We began government-to-government consultation with 
these tribes prior to the publication of the proposed rule, through the 
public comment period, and during the development of the final listing 
determination.
    We sent letters in September 2012 to each Tribe seeking early input 
regarding the species status review and to offer government-to-
government consultation. We sent notification letters in October and 
November of 2013 to each Tribe describing the critical habitat 
exclusion process under section 4(b)(2) of the Act, and we engaged in 
conversation with the Tribes about the proposed listing and critical 
habitat rules to the extent possible. We have maintained contact with 
Flandreau Santee Sioux Tribe, Turtle Mountain Chippewa, Three 
Affiliated Tribes, Spirit Lake Sioux Tribe, and Standing Rock Sioux 
Tribe through letters, phone calls, and emails, and we notified each 
tribe when documents pertaining to the listing and critical habitat 
rules were made available.
    We have coordinated several survey efforts with Sisseton-Wahpeton 
Oyate since 1995 and held an informational meeting for the Tribe in 
April 2014, to better explain the proposed listing and designation of 
critical habitat. We met with representatives from the Turtle Mountain 
Chippewa in May 2014, and conducted a site visit at that time to 
evaluate areas proposed for designation as critical habitat. We did not 
receive comments from the Sisseton-Wahpeton Oyate, Three Affiliated 
Tribes, Standing Rock Sioux Tribe, Flandreau Santee Sioux Tribe, Turtle 
Mountain Chippewa, or the Spirit Lake Nation. However, notification of 
the available economic analysis screening memorandum for the critical 
habitat proposal was provided to all Tribes in the species' ranges at 
the time it was made available to the public.

References Cited

    A complete list of references cited in this rulemaking is available 
on the Internet at http://www.regulations.gov and upon request from the 
Twin Cities Ecological Services Field Office (see FOR FURTHER 
INFORMATION CONTACT).

Authors

    The primary authors of this final rule are the staff members of the 
Twin Cities Ecological Services Field Office.

List of Subjects in 50 CFR Part 17

    Endangered and threatened species, Exports, Imports, Reporting and 
recordkeeping requirements, Transportation.

Regulation Promulgation

    Accordingly, we amend part 17, subchapter B of chapter I, title 50 
of the Code of Federal Regulations, as follows:

PART 17--[AMENDED]

0
1. The authority citation for part 17 continues to read as follows:

    Authority: 16 U.S.C. 1361-1407; 1531-1544; 4201-4245; unless 
otherwise noted.


0
2. Amend Sec.  17.11(h) by adding entries for ``Skipper, Dakota'' and 
``Skipperling, Poweshiek'' to the List of Endangered and Threatened 
Wildlife in alphabetical order under ``Insects'' to read as follows:

[[Page 63748]]

Sec.  17.11  Endangered and threatened wildlife.

* * * * *
    (h) * * *

--------------------------------------------------------------------------------------------------------------------------------------------------------
                     Species                                              Vertebrate
--------------------------------------------------                     population where                                           Critical     Special
                                                     Historic range     endangered or             Status           When listed    habitat       rules
          Common name            Scientific name                          threatened
--------------------------------------------------------------------------------------------------------------------------------------------------------
 
                                                                      * * * * * * *
            Insects
 
                                                                      * * * * * * *
Skipper, Dakota...............  Hesperia dacotae.  U.S.A. (IA, IL,    NA...............  T                                 851           NA     17.47(b)
                                                    MN, ND, SD);
                                                    Canada
                                                    (Manitoba,
                                                    Saskatchewan).
 
                                                                      * * * * * * *
Skipperling, Poweshiek........  Oarisma poweshiek  U.S.A. (IA, IL,    NA...............  E                                 851           NA           NA
                                                    IN, MI, MN, ND,
                                                    SD, WI,); Canada
                                                    (Manitoba).
 
                                                                      * * * * * * *
--------------------------------------------------------------------------------------------------------------------------------------------------------

* * * * *

0
3. Amend Sec.  17.47 by adding paragraph (b) to read as follows:


Sec.  17.47  Special rules--insects.

* * * * *
    (b) Dakota skipper (Hesperia dacotae).
    (1) Which populations of the Dakota skipper are covered by this 
special rule? This rule covers the distribution of Dakota skipper in 
the United States.
    (2) Prohibitions. Except as noted in paragraph (b)(3) of this 
section, all prohibitions and provisions of Sec. Sec.  17.31 and 17.32 
apply to the Dakota skipper.
    (3) Exemptions from prohibitions. Incidental take of Dakota skipper 
will not be a violation of section 9 of the Act if it occurs as a 
result of the following activities (except where explicitly stated 
otherwise, these activities must be associated with livestock 
ranching):
    (i) Fence construction and maintenance.
    (ii) Livestock gathering and management. The installation and 
maintenance of corrals, loading chutes, and other livestock working 
facilities must be carefully sited with respect to the location and 
distribution of important Dakota skipper habitat.
    (iii) Development and maintenance of livestock watering facilities.
    (iv) Noxious weed control. Incidental take of Dakota skipper that 
results from spraying of herbicides is not a violation of section 9 of 
the Act, except such take that results from broadcast spraying, which 
is the application of herbicides evenly across the entire application 
area. Incidental take that results from mowing to control one or more 
noxious weed species would also not be a violation of section 9 of the 
Act.
    (v) Haying. For the purposes of this rule, native haylands do not 
include lands that had previously been plowed and were then replanted 
to native or nonnative vegetation, but native haylands do include areas 
within transportation (e.g., road, highway, railroad) rights-of-ways 
and corridors where native grasses are mowed for hay. Haying of native 
haylands no earlier than July 16 (after July 15) would not be a 
violation of section 9 of the Act. Mowing of replanted grasslands 
(grasslands replanted on formerly plowed or cultivated lands) or tame 
haylands or grasslands (planted hayland or grassland comprising 
primarily nonnative grass species, such as smooth brome (Bromus inermis 
inermis)) would also not be a violation of section 9 of the Act at any 
time of the year.
    (vi) Mowing section line rights-of-way and recreational trails. 
Mowing of section line rights-of-way (typically disturbed soil that has 
been contoured for a roadway) would not be a violation of section 9 of 
the Act. Mowing of recreational trails (travelways established either 
through construction or use that are intended for and passable by foot 
traffic, bicycles, in-line skates, wheelchairs, or cross-country skis) 
would not be a violation of section 9 of the Act, regardless of whether 
the trails are associated with livestock ranching.
    (vii) Livestock (cattle, bison, or horse) grazing on private, 
State, or tribal land.

    Dated: October 15, 2014.
Stephen Guertin,
Acting Director, U.S. Fish and Wildlife Service.
[FR Doc. 2014-25190 Filed 10-23-14; 8:45 am]
BILLING CODE 4310-55-P