[Federal Register Volume 76, Number 105 (Wednesday, June 1, 2011)]
[Proposed Rules]
[Pages 31685-31747]
From the Federal Register Online via the Government Printing Office [www.gpo.gov]
[FR Doc No: 2011-12947]



[[Page 31685]]

Vol. 76

Wednesday,

No. 105

June 1, 2011

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; Revised Critical Habitat 
for the Riverside Fairy Shrimp; Proposed Rule

Federal Register / Vol. 76 , No. 105 / Wednesday, June 1, 2011 / 
Proposed Rules

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DEPARTMENT OF THE INTERIOR

Fish and Wildlife Service

50 CFR Part 17

[Docket No. FWS-R8-ES-2011-0013; MO 92210-0-009]
RIN 1018-AX15


Endangered and Threatened Wildlife and Plants; Revised Critical 
Habitat for the Riverside Fairy Shrimp

AGENCY: Fish and Wildlife Service, Interior.

ACTION: Proposed rule.

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SUMMARY: We, the U.S. Fish and Wildlife Service (Service), propose to 
revise the currently designated critical habitat for the Riverside 
fairy shrimp (Streptocephalus woottoni) under the Endangered Species 
Act of 1973, as amended (Act). The current critical habitat consists of 
306 acres (124 hectares) of land in four units in Ventura, Orange, and 
San Diego Counties, California. We now propose to designate 
approximately 2,984 acres (1,208 hectares) of land in five units in 
Ventura, Orange, Riverside, and San Diego Counties, California, which, 
if finalized as proposed, would result in an increase of approximately 
2,678 acres (1,084 hectares) of critical habitat for this species.

DATES: We will consider comments received or postmarked on or before 
August 1, 2011. We must receive requests for public hearings, in 
writing, at the address shown in the FOR FURTHER INFORMATION CONTACT 
section by July 18, 2011.

ADDRESSES: You may submit comments by one of the following methods:
    (1) Federal eRulemaking Portal: http://www.regulations.gov. Follow 
the instructions for submitting comments to Docket Number FWS-R8-ES-
2011-0013.
    (2) U.S. mail or hand-delivery: Public Comments Processing, Attn: 
FWS-R8-ES-2011-0013; Division of Policy and Directives Management; U.S. 
Fish and Wildlife Service; 4401 N. Fairfax Drive, MS2042; Arlington, VA 
22203.
    We will not accept e-mail or faxes. We will post all comments on 
http://www.regulations.gov. This generally means that we will post any 
personal information you provide us (see the Public Comments section 
below for more information).

FOR FURTHER INFORMATION CONTACT: Jim Bartel, Field Supervisor, U.S. 
Fish and Wildlife Service, Carlsbad Fish and Wildlife Office, 6010 
Hidden Valley Road, Suite 101, Carlsbad, CA 92011; telephone 760-431-
9440; facsimile 760-431-5901. If you use a telecommunications device 
for the deaf (TDD), call the Federal Information Relay Service (FIRS) 
at 800-877-8339.

SUPPLEMENTARY INFORMATION: 

Public Comments

    We intend that any final action resulting from this proposed rule 
will be based on the best scientific and commercial data available and 
be as accurate and as effective as possible. Therefore, we request 
comments or information from other concerned government agencies, the 
scientific community, industry, or other interested party concerning 
this proposed rule. We particularly seek comments concerning:
    (1) The reasons why we should or should not revise the designation 
of habitat as ``critical habitat'' under section 4 of the Act (16 
U.S.C. 1531 et seq.), including whether there are threats to the 
species from human activity, the degree of which can be expected to 
increase due to the designation, and whether that increase in threat 
outweighs the benefit of designation such that the designation of 
critical habitat may not be prudent.
    (2) Specific information on:
    (a) The amount and distribution of Riverside fairy shrimp habitat;
    (b) What areas occupied at the time of listing (or currently 
occupied) and containing features essential to the conservation of the 
species, should be included in the designation and why;
    (c) What areas not occupied at the time of listing are essential 
for the conservation of the species and why;
    (d) Special management considerations or protection that the 
features essential for the conservation of the species may require, 
including management for potential impacts associated with climate 
change; and
    (e) Areas identified in this proposed revised critical habitat rule 
that should not be proposed as critical habitat and why.
    (3) Land-use designations and current or planned activities in the 
subject areas and their possible impacts on proposed revised critical 
habitat.
    (4) Information that may assist us in identifying or clarifying the 
physical and biological features essential to the conservation of 
Riverside fairy shrimp.
    (5) Special management considerations or protection that the 
physical and biological features essential to the conservation of the 
species may require.
    (6) Specific information regarding the occurrence, or non-
occurrence, of Riverside fairy shrimp in the Cruzan Mesa vernal pools 
(in Los Angeles County) and, if the species is present, whether this 
area is essential to the conservation of the species and if so, whether 
the area should be considered for exclusion under section 4(b)(2) of 
the Act and why.
    (7) Specific information on the habitat conditions for Riverside 
fairy shrimp and the presence of physical and biological features 
essential for the conservation of the species in Subunit 1b (South of 
Tierra Rejada Valley, which is in Ventura County), and whether this 
area is essential to the conservation of the species and why.
    (8) Specific information regarding the occurrence of Riverside 
fairy shrimp within proposed Subunit 3h (Santa Rosa Plateau at Mesa de 
Colorado, which is in western Riverside County), whether this area is 
essential to the conservation of the species, and if so, whether the 
area should be considered for exclusion under section 4(b)(2) of the 
Act and why.
    (9) Specific information regarding a potential occurrence of 
Riverside fairy shrimp at Madrona Marsh (Los Angeles County) and, if 
the species is present, whether this area is essential to the 
conservation of the species and why.
    (10) Specific information regarding the presence or absence of the 
physical and biological features essential to the conservation of the 
species within proposed Subunit 5c, and whether this area is essential 
to the conservation of the species and why.
    (11) Information on the projected and reasonably likely impacts 
associated with climate change on Riverside fairy shrimp and the areas 
we are proposing to designate as critical habitat.
    (12) How the proposed revised critical habitat boundaries could be 
refined to more closely circumscribe the landscapes identified as 
containing the physical and biological features essential to the 
conservation of the Riverside fairy shrimp.
    (13) Any probable economic, national security, or other relevant 
impacts of designating any area that may be included in the final 
designation; in particular, any impacts on small entities or families, 
and the benefits of including or excluding areas that exhibit these 
impacts.
    (14) Whether the potential exclusion under section 4(b)(2) of the 
Act of Subunits 2c ((MCAS) El Toro) and 2i (Southern California Edison 
(SCE) Viejo Conservation Bank), which are covered by the Orange County 
Central-Coastal Natural Community Conservation Plan/Habitat 
Conservation Plan (Orange County Central-Coastal NCCP/HCP), from final 
revised critical habitat is or

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is not appropriate, and whether the benefits of excluding any specific 
area outweigh the benefits of including that area as critical habitat 
and why.
    (15) Whether the potential exclusion under section 4(b)(2) of the 
Act of a portion of Subunit 2dA (Saddleback Meadows); portions of 
Subunit 2dB (O'Neill Regional Park--near Trabuco Canyon) and 2e 
(O'Neill Regional Park--near Ca[ntilde]ada Gobernadora/east of Tijeras 
Creek); and Subunits 2f (Chiquita Ridge) and 2g (Radio Tower Road), 
which are covered by the Southern Orange County Natural Community 
Conservation Plan (NCCP)/Master Streambed Alteration Agreement/Habitat 
Conservation Plan (HCP), now known as the Orange County Southern 
Subregion HCP, from final revised critical habitat is or is not 
appropriate, and whether the benefits of excluding any specific area 
outweigh the benefits of including that area as critical habitat and 
why.
    (16) Whether the potential exclusion under section 4(b)(2) of the 
Act of Subunits 3c, 3d, 3e, 3f, 3g, and 3h, which are covered by the 
Western Riverside County Multiple Species Habitat Conservation Plan 
(the Western Riverside County MSHCP) from final revised critical 
habitat is or is not appropriate, and whether the benefits of excluding 
any specific area outweigh the benefits of including that area as 
critical habitat and why.
    (17) Whether the potential exclusion under section 4(b)(2) of the 
Act of Subunit 4c (Poinsettia Lane Commuter Station) as critical 
habitat covered by the Carlsbad Habitat Management Plan (Carlsbad HMP), 
a subarea plan under the Multiple Habitat Conservation Program (MHCP), 
from final revised critical habitat is or is not appropriate, and 
whether the benefits of excluding any specific area outweigh the 
benefits of including that area as critical habitat and why.
    (18) Whether the potential exclusion under section 4(b)(2) of the 
Act--portions of Subunit 5d, which is covered by the County of San 
Diego Subarea Plan under the San Diego Multiple Species Conservation 
Program (MSCP) from final revised critical habitat is or is not 
appropriate, and whether the benefits of excluding any specific area 
outweigh the benefits of including that area as critical habitat and 
why.
    (19) Although we are not proposing areas within tribal lands in 
this proposed rule, we seek specific information regarding the possible 
species occurrence within two vernal pools on or near tribal land of 
the Pechanga Band of Luise[ntilde]o Mission Indians of the Pechanga 
Reservation, California (Pechanga Band of Luise[ntilde]o Mission 
Indians), and, if the species is present, whether this area is 
essential to the conservation of Riverside fairy shrimp and why.
    (20) Although we are not considering for exclusion lands owned by 
the Department of Homeland Security (DHS) along the U.S.-Mexico border 
in this proposed rule (Subunit 5b and a portion of land in 5h), we seek 
comments on whether or not these lands should be considered for 
exclusion under section 4(b)(2) of the Act of Federal land for national 
security reasons, whether such exclusion is or is not appropriate, and 
whether the benefits of excluding any specific area outweigh the 
benefits of including that area as critical habitat and why.
    (21) Whether our exemption, under section 4(a)(3)(B) of the Act, of 
land on Department of Defense property at Marine Corps Base (MCB) Camp 
Pendleton and Marine Corps Air Station (MCAS) Miramar in San Diego 
County is or is not appropriate, and why.
    (22) Whether the benefit of exclusion of any other particular area 
not specifically identified above outweighs the benefit of inclusion 
under section 4(b)(2) of the Act.
    (23) Information on any quantifiable economic costs or benefits of 
the proposed revised designation of critical habitat.
    (24) Whether we could improve or modify our approach to designating 
critical habitat in any way to provide for greater public participation 
and understanding, or to better accommodate concerns and comments.
    Our final determination concerning the revision of Riverside fairy 
shrimp critical habitat will take into consideration all written 
comments and any additional information we receive during all comment 
periods. The comments will be included in the public record for this 
rulemaking, and we will fully consider them in the preparation of our 
final determination. On the basis of public comments, we may, during 
the development of our final determination, find that areas within the 
proposed designation do not meet the definition of critical habitat, 
that some modifications to the described boundaries are appropriate, or 
that areas may or may not be appropriate for exclusion under section 
4(b)(2) of the Act.
    You may submit your comments and materials concerning this proposed 
rule by one of the methods listed in the ADDRESSES section. We will not 
accept comments sent by e-mail or fax or to an address not listed in 
the ADDRESSES section. We will post your entire comment--including your 
personal identifying information--on http://www.regulations.gov. You 
may request at the top of your document that we withhold personal 
information such as your street address, phone number, or e-mail 
address from public review; however, we cannot guarantee that we will 
be able to do so.
    Comments and materials we receive, as well as supporting 
documentation we used in preparing this proposed rule, will be 
available for public inspection on http://www.regulations.gov, or by 
appointment, during normal business hours, at the U.S. Fish and 
Wildlife Service, Carlsbad Fish and Wildlife Office (see FOR FURTHER 
INFORMATION CONTACT).

Background

    It is our intent to discuss only those topics directly relevant to 
the proposed revision of critical habitat for Riverside fairy shrimp. 
This proposed rule incorporates new information specific to Riverside 
fairy shrimp genetics across the species' range that was not available 
when we completed our 2005 final critical habitat designation (70 FR 
19154; April 12, 2005), and new information on the status and 
distribution of Riverside fairy shrimp that became available since the 
2005 final critical habitat designation for this species. A summary of 
topics that are relevant to this proposed revised critical habitat 
designation is provided below. For more information on the taxonomy, 
biology, and ecology of Riverside fairy shrimp, please refer to the 
final listing rule published in the Federal Register on August 3, 1993 
(58 FR 41384); the first and second rules proposing critical habitat 
published in the Federal Register on September 21, 2000 (65 FR 57136), 
and April 27, 2004 (69 FR 23024), respectively; and the subsequent 
final critical habitat designations published in the Federal Register 
on May 30, 2001 (66 FR 29384), and April 12, 2005 (70 FR 19154). 
Additionally, more species information can be found in the 1998 
Recovery Plan for the Vernal Pools of Southern California (1998 
Recovery Plan) finalized on September 3, 1998 (Service 1998a, pp. 1-
113), in the City of San Diego's 2002-2003 Vernal Pool Inventory (City 
of San Diego 2004, pp. 1-125), and in the Riverside fairy shrimp 5-year 
review (Service 2008, pp. 1-57).

Species Description

    The Riverside fairy shrimp is a small (0.56 to 0.92 inch (in)) (14 
to 23 millimeter (mm)) aquatic crustacean in the order Anostraca, 
restricted to

[[Page 31688]]

seasonal (vernal) pools, ponds, swales, and other pool-like, ephemeral 
(lasting a short time) water bodies in southern coastal California, 
United States, and northern Baja California, Mexico (Eng et al. 1990, 
pp. 258-259). Riverside fairy shrimp, like all fairy shrimp in general, 
have stalked compound eyes, no carapace (hard outer shell), and eleven 
pairs of phyllopods (swimming legs that also function as gills). They 
swim or glide upside down by means of complex beating movements of the 
legs that pass, wave-like, in an anterior to posterior direction. Male 
and females have red-colored cercopods (anterior appendages) on all of 
the ninth and 30 to 40 percent of the eighth abdominal segments, which 
helps to distinguish this species from closely related species (Eng et 
al. 1990, p. 259).
    First collected in 1979 and described as a new species by Eng et 
al. (1990, pp. 258-259), based on a type specimen collected from an 
area between Murrieta Golf Course and California Highway 79 in 
Riverside County (71 FR 14538), Riverside fairy shrimp are currently 
presumed to occupy 60 or fewer pool complexes throughout southern 
California (see Spatial Distribution and Historical Range below). At 
the time the species was listed as endangered in 1993, the type 
locality had been lost to development (Eriksen and Belk 1999, p. 104; 
Service 2008, p. 5).

Habitat

    Typical habitat for fairy shrimp in California includes vernal 
pools, seasonally ponded areas within vernal swales, and ephemeral 
freshwater habitats (68 FR 46685). Riverside fairy shrimp are 
considered habitat specialists, found in moderate to deep (generally 
ranging from 10 inches (in) (25.4 centimeters (cm)) to 5 to 10 feet 
(ft) (1.5 to 3 meters (m)) in depth), longer-lived vernal pools and 
ephemeral wetlands (Eng et al. 1990, p. 259; Simovich and Fugate 1992, 
pp. 7-8; Hathaway and Simovich 1996, p. 39) because of specific life-
history traits and habitat needs (see Life History section below).
    Riverside fairy shrimp's known localities are below 2,100 ft (640 
m) elevation and are within 50 miles (mi) (80 kilometers (km)) of the 
Pacific Ocean. Riverside fairy shrimp do not occur in riverine or 
marine waters or other permanent bodies of water. Water chemistry is an 
important factor in determining fairy shrimp distribution (Belk 1977, 
p. 77; Gonzales et al. 1996, p. 319). As previously described in the 
final listing rule (58 FR 41384; August 3, 1993) and the Background 
section of the final revised critical habitat rule (70 FR 19154; April 
12, 2005), vernal pool habitats that support Riverside fairy shrimp 
occur in areas with Mediterranean climates (cool, wet winters and hot, 
dry summers), where shallow depressions become seasonally wet or 
inundated following winter and spring rains (Keeley and Zedler 1998, p. 
2; Smith and Verrill 1998, p. 15). In general, vernal pools occur as 
poorly drained depressions, perched above an impermeable surface or 
very slowly permeable soil horizon or bedrock (Cheatham 1976, p. 88; 
Smith and Verrill 1998, p. 15); restrictive soil layers are typically 
hardpan or claypan, and bedrock types are volcanic mud or lava flows 
(Jones and Stokes 1987, p. 70; Zedler 1987, p. 13; Smith and Verrill 
1998, p. 15). Other kinds of depressions that hold water of a similar 
volume, depth, and area, and for a similar duration and seasonality as 
vernal pools and ponded areas within swales, may also provide potential 
habitat for Riverside fairy shrimp.
    Vernal pools may fill primarily by direct precipitation, or may 
have contributions from subsurface inflows from surrounding soils, 
which may help to minimize water level fluctuations during late winter 
and early spring (Hanes and Stromberg 1998, p. 48; Rains et al. 2006, 
p. 1158). Although vernal pools may typically associate with specific 
types of geological formations, landforms, and soils and within 
different types of ephemeral wetland landscapes (Zedler 1987, p. 13; 
Hanes and Stromberg 1998, p. 48; Smith and Verrill 1998, p.15; Rains et 
al. 2006, p. 1158), the most common unifying feature to fairy shrimp 
habitat, in general, is ephemerally wet, flooded, or ponded area that 
is typically wet during a portion of the year and dry for the remainder 
of the year.
    Throughout this proposed revised critical habitat rule, the term 
``ephemeral wetlands'' refers to vernal pool habitats including vernal 
lakes, ponds, detention basins, and other natural and manmade 
depressions that seasonally hold water. While these ephemeral wetlands 
often occur within landscapes of ``mima-mound'' topography (Cox 1984, 
pp. 1397-1398), that is, they form during winter rains as a natural 
hydrological feature of a gently sloping, undulating landscape, the 
species can also be found in disturbed vernal pool habitats where 
basins have been compacted or artificially deepened and therefore hold 
water for longer periods of time.
    Depending on topography, soils, and geographic location, the period 
of time varies during which these ephemeral wetlands pond (referred to 
as the ``period of inundation''). Basin size and basin shape (Keeley 
and Zedler 1998, p. 5), soil type, soil consistency, depth of soil to 
impervious layer (for example, hardpan or claypan), type and thickness 
of impervious layer, and other local and regional climatic factors (for 
example, rainfall abundance and timing, rainfall regularity, and 
evaporation rates) (Keeley and Zedler 1998, p. 2; Helm 1998, p. 136) 
all are variables that potentially affect the length of ponding in 
vernal pool landscapes. For southern California's ephemeral wetlands, 
the wet phase typically occurs between the months of October to May, 
and the dry phase lasts for a period of time between the months of June 
to September.
    The Riverside fairy shrimp often hatches later in the season than 
other fairy shrimp species because presumably the deeper pools it 
inhabits require sufficient rainfall to fill (Simovich and Fugate 1992, 
p. 8). A minimum period of inundation, or pool duration, that Riverside 
fairy shrimp need in order to hatch and reach sexual maturity is 
approximately 8 weeks (48 to 56 days) based on field observations 
(Hathaway and Simovich 1996, p. 674) (see Life History section below 
for further discussion).
    Mounds of soil (mima) (Scheffer 1947, p. 288), or swales (broad, 
shallow, vegetated, ephemerally wet areas) (Helm 1998, p. 130), that 
are interconnected with level or low point depressional basins and 
which contain appropriate impervious clay soils (providing ponding 
opportunities during winter and spring), are geographically fixed and 
limited in number. Soils and soil series that underlie vernal pool 
habitat that supports Riverside fairy shrimp are generally 
characterized by a high content of coarse sandy grains (marine alluvial 
sediments), loams, or clay inclusions, or a combination of these, with 
a subsurface clay or hardpan layer. These are also limited in number 
and geographically fixed. Riverside fairy shrimp are known to occur in 
both hardpan and claypan vernal pools in Ventura, San Diego, Los 
Angeles (now extirpated), Riverside, and Orange Counties, and in 
addition, in Riverside County on granitic (basaltic) substrate.
    Vernal pools and vernal swales are often clustered into pool 
``complexes'' (Bauder 1986a, Appendix 1, 4; Keeler-Wolf et al. 1998, 
pp. 60-61, 63-64), and may form dense, interconnected mosaics of small 
pools, or a sparse scattering of larger pools. Vernal pool complexes 
that support from one up to many distinct vernal pools are often 
interconnected by a shared watershed. Both the pool basin and the 
surrounding watershed are essential for a functioning vernal pool 
system (Hanes and

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Stromberg 1998, p. 48). Loss of upland vegetation, increased overland 
water flow due to urban runoff, and alteration of the microtopography 
can modify the function of vernal pool systems, and alter the 
physiochemical parameters that the Riverside fairy shrimp requires for 
survival. Because the Riverside fairy shrimp requires ephemerally 
ponded areas for its conservation (Belk 1998, pp. 147-148), vernal 
pools are best described from a watershed perspective (see Physical and 
Biological Features section below, and Recovery Criteria 1 and 2 in the 
1998 Recovery Plan for Vernal Pools of Southern California (Service 
1998a, pp. iv-vi)).
    The size and number of inundated basins and their associated biota 
are directly correlated to the amount and timing of precipitation (City 
of San Diego 2004, p. 6). In southern California, rainfall is erratic 
within and between years as well as strongly seasonal (Zedler 1987, p. 
12). Pool size, location and elevation, upland hydrology, 
physiochemical processes, and unique species assemblages may all factor 
into the distribution of vernal pool species (Eng et al. 1990, p. 273; 
Branchiopod Research Group 1996, pp. 1-2; Gonzalez et al. 1996, p. 
319). Water chemistry (dissolved solutes, alkalinity, salinity, and 
temperature) and length of time vernal pools are inundated with water 
(see Life History section below) are important factors that potentially 
limit and determine the distribution of Riverside fairy shrimp within 
and among pools complexes.
    Water in the pools that typically support Riverside fairy shrimp 
has low total dissolved solids and alkalinity (means of 77 and 65 
milligrams per liter (mg/l) or parts per million (ppm), respectively), 
corroborated by pH at neutral or just below (6.4-7.1) (Eng et al. 1990, 
p. 254; Gonzalez et al. 1996, p. 317; Eriksen and Belk 1999, p. 104). 
Riverside fairy shrimp have been shown to tightly regulate their 
internal body chemistry for pool environments that have low salinity 
and low alkalinity (Gonzalez et al. 1996, pp. 317-318). Pools are 
generally open and unvegetated with turbid water conditions; habitat 
lies within annual grasslands, which may be interspersed through 
chaparral or coastal sage scrub vegetation (Lahti et al. 2010, p. 5). 
Riverside fairy shrimp are typically found in water temperatures 
ranging between 50 and 77 degrees Fahrenheit (10 and 25 degrees 
Celsius) (Hathaway and Simovich 1996, p. 671).

Life History

    As discussed in detail in the Background section of the final 
revised critical habitat rule (70 FR 19154; April 12, 2005), Riverside 
fairy shrimp feed on algae, bacteria, protozoa, rotifers, and bits of 
detritus, and constitute a cornerstone in the food web for a wide array 
of aquatic and terrestrial species.
    Because vernal pool ecosystems are highly variable in the length of 
time pools remain filled, Riverside fairy shrimp have adapted their 
life-history strategies accordingly. Riverside fairy shrimp populations 
withstand a seasonal desiccation of their pools by producing resting 
eggs (herein referred to as reproductive cysts), which when mature can 
survive environmental conditions such as extremes in temperatures, the 
digestive tracts of animals, and years of desiccation before hatching 
under the correct environmental conditions (Pennak 1989, pp. 352-353; 
Eriksen and Belk 1999, p. 22). Because not all reproductive cysts will 
hatch with any given refilling of their pool, these reproductive cysts 
form a ``cyst bank'' in the soil from which new populations of adults 
may develop, even in pools that have not had adults for years (Eriksen 
and Belk 1999, p. 105). Therefore, it is not mandatory for ideal 
conditions to exist every year for this species to persist.
    Adult Riverside fairy shrimp are usually observed from mid-March to 
April (Eng et al. 1990, p. 259); however, the hatching periods may be 
extended in years with early or late rainfall. Unlike San Diego fairy 
shrimp (Branchinecta sandiegonensis), a species that matures quickly (7 
to 14 days), Riverside fairy shrimp hatch and mature within 48 to 56 
days, depending on water temperature (Hathaway and Simovich 1996, p. 
674; Simovich and Hathaway 1997, p. 39; Eriksen and Belk 1999, p. 105). 
Because of its distinctly longer maturation, Riverside fairy shrimp are 
typically restricted to relatively deep (greater than 12 in (30 cm)), 
cool water vernal pools that are inundated for a longer time to 
complete their reproductive life cycle (Hathaway and Simovich 1996, p. 
675) . This longer deve1opment time is thought to account for the 
species' restriction to deep pools, their rarity, and later appearance 
(Simovich and Fugate 1992, p. 8).

Spatial Distribution and Historical Range

    As discussed in detail in the Background section of the final 
revised critical habitat rule (70 FR 19154; April 12, 2005), Riverside 
fairy shrimp are considered to have one of the most restricted 
distributions among fairy shrimps endemic to the West Coast (Eng et al. 
1990; p. 259, Simovich and Fugate 1992, p. 7; Eriksen and Belk 1999, p. 
104). Because the Riverside fairy shrimp has a slower developmental 
rate, the species is limited to fairly deep, and moderate in size, 
pools that support a longer ponding duration. The Riverside fairy 
shrimp is, therefore, restricted to a subset of vernal pools and vernal 
pool complexes in southern California (Ventura, Orange, Riverside, and 
San Diego Counties) and in northern Mexico (Service 1998a, p. 19; 
Eriksen & Belk 1999, p. 104). The Riverside fairy shrimp has likely 
been extirpated from Los Angeles County. With the exception of the 
Riverside County populations, all populations are within approximately 
15 mi (24 km) of the coast. Riverside fairy shrimp range over a north-
south distance of approximately 163 mi (262 km) within southern 
California (excluding Baja, Mexico locations) and occupy pools that 
range in elevation from 46 to 2,076 ft (14 to 633 m).
    For the purposes of this proposed revised critical habitat 
designation, the word occurrence may be a single pool or a pool 
complex. Keeler-Wolf et al. (1998, p. 8) define a vernal pool complex 
as a set of naturally occurring pools in close proximity. A singular 
pool--geographically situated such that the pool basin is isolated from 
adjoining vernal pool topography by distances greater than 10 mi (16 
km)--or a network of one or more vernal pool basins in close proximity, 
that is to say a vernal pool complex, may comprise an occurrence. At 
the time of listing in 1993, nine historical occurrences for Riverside 
fairy shrimp were known: Four occurrences in a 37-square-mile (91-
square-km) area near Temecula, California (western Riverside County); 
one occurrence in Orange County, California; two documented occurrences 
in San Diego County, California; and two occurrences in Baja 
California, Mexico (58 FR 41384; August 3, 1993).
    In our 2008 5-year review of Riverside fairy shrimp, we assembled 
and reassessed occurrence data for the species (Service 2008, pp. 6-8). 
Seven of the nine historical occurrences (five in the United States and 
two in Mexico) were presumed extant at the time Riverside fairy shrimp 
was listed in 1993 (Service 2008, pp. 7-8). The type locality in 
western Riverside County (at Murrieta Golf Course) was already 
extirpated by the time the species was listed, and the single-
referenced occurrence from Orange County has never been confirmed. 
Based on our analysis in the 2008 5-year review for Riverside fairy 
shrimp, with the discovery of additional occurrences, the regrouping of 
vernal pool complexes, and the extirpation of nine known occurrences 
since listing, we concluded

[[Page 31690]]

that there were approximately 45 known extant (or presumed extant) 
occurrences (approximately 200 vernal pools) of Riverside fairy shrimp 
(Service 2008, p. 5). Discovery of additional occurrences since the 
time of the 1998 Recovery Plan, include at least four more occurrences, 
all in western Riverside County: Warm Springs Ranch Pool, Schau Pool, 
Rancho California Road Pools, and an occurrence (two pools, Pool 4 and 
Pool 5 in Selheim and Searcy 2010, p. 98) atop Santa Rosa Plateau along 
Mesa de Colorado. Identification of additional occurrences since 
listing (1993) has resulted from surveys conducted in locations that 
were not surveyed prior to 1993. In sum, Riverside fairy shrimp are 
presently considered to be extant in approximately 49 occurrences 
(vernal pools and vernal pool complexes), four more than we reported in 
the 2008 5-year review (Service 2008, pp. 5, 10).
    Extant occurrences not identified in the 1993 listing rule (but 
presumed extant at the time of listing) are located in the following 
general areas: (1) One occurrence in Ventura County (Tierra Rejada 
Preserve and South of Tierra Rejada Valley); (2) seven occurrences in 
Orange County: (MCAS) El Toro, SCE Viejo Conservation Bank, Saddleback 
Meadows, O'Neill Regional Park--near Trabuco Canyon, O'Neill Regional 
Park--near Ca[ntilde]ada Gobenadora/east of Tijeras Creek, Chiquita 
Ridge, and Radio Tower Road; (3) nine occurrences in Riverside County 
at the Australia Pool, the Scott Road Pool, the Warm Springs Ranch 
Pools, the Schleuniger Pool, the Schau Pool, in the Johnson Ranch area, 
the Field Pool, the Rancho California Road Pool, and a newly documented 
occurrence on the Santa Rosa Plateau along Mesa de Colorado; (4) ten 
occurrences in north San Diego County on MCB Camp Pendleton: San Onofre 
State Beach, State Park-leased lands, near Christianitos Creek 
foothills (along the northwest corner of MCB Camp Pendleton); area 
south of San Onofre State Beach, in Uniform Training Area; Las Pulgas 
North; Las Pulgas East; Las Pulgas West; Cockleburr North; Cockleburr 
South; Stuart Mesa; San Mateo; and Wire Mountain; and (5) seven 
occurrences in central and southern San Diego County, outside of MCB 
Camp Pendleton: on MCAS Miramar (AA1 pool); City of Carlsbad 
(Poinsettia Lane Commuter Train Station); and numerous pools on Otay 
Mesa (southern San Diego County) including what is referred to as the 
``J series'' of vernal pool complexes (J2, J4, J5, J11, J12, J14, J15, 
J16-18, J29-31, J33).
    For the purpose of this proposed revised critical habitat 
designation, we consider areas where Riverside fairy shrimp have been 
documented since listing (since 1993) to be within the geographical 
area occupied by the species at the time of listing (in 1993). As 
discussed in the 5-year review, most of the additional occurrences 
identified since listing fall generally within the range of the 
Riverside fairy shrimp described in the listing rule, although the 
identification of some occurrences (complexes) broadened the specific 
range within Ventura, Orange, Riverside, and San Diego Counties 
(Service 2008, p. 8). As with many species, listing often results in 
greater efforts to conduct surveys, which may reveal a greater number 
of occurrences than was initially known.
    We believe that these additional occurrences were occupied at the 
time of listing but had not been identified due to lack of survey 
effort. We believe occurrences documented since the 1993 listing do not 
represent an expansion of the species' distribution and range into 
previously unoccupied areas (with the exception of Johnson Ranch 
Created Pools), but rather a better understanding of the historical 
distribution and range of the species (Service 2008, p. 9). Because 
occurrences documented since listing are within relative proximity to 
existing, occupied, vernal pool habitat or within similar landscape 
types (e.g., coastal terraces and mesas, inland valleys, inland mesas, 
cismontane depressions) supporting ephemeral wetlands with occurrences 
that were known at the time of listing, it is reasonable to conclude, 
based on several life-history traits, that Riverside fairy shrimp were 
present at the time of listing in these unsurveyed habitats.
    Riverside fairy shrimp are generally sedentary and are adapted to 
survive and persist in seasonally ephemeral habitat. Because they are 
sedentary, possess limited dispersal capabilities (passive dispersal 
mediated by resistant stages), and exhibit specialized habitat 
affinities (specific habitat types with fixed landscape features, see 
Life History and Habitat sections of this document), we believe it is 
unlikely that additional occurrences have become established during the 
relatively short time period since the listing of this species (with 
the exception of Johnson Ranch Created Pools). With the exception of 
the land we are proposing to designate under section 3(5)(A)(ii) of the 
Act--Johnson Ranch Created Pools (in Riverside County), which were 
created after the species was listed--we consider all known occurrences 
to be occupied at the time of listing and within the geographical area 
occupied by the species at the time of listing in this proposed 
critical habitat designation. Therefore, throughout this proposed rule, 
we refer to all occurrences (with the exception of Johnson Ranch 
Created Pools) as being occupied at the time of listing whether the 
areas were documented before or after the species was listed.
    We are designating one area, Johnson Ranch Created Pools, as 
essential under section 3(5)(A)(ii) of the Act. Although this area 
falls within the currently occupied geographic range of the species, at 
the time Riverside fairy shrimp was listed, it was not occupied.
    Each area that we are proposing as revised critical habitat 
contains a currently extant (or in the case of Subunit 1b, considered 
extant) occurrence of Riverside fairy shrimp; however, Riverside fairy 
shrimp do not physically occur throughout the entirety of each area. 
The 2,984 ac (1,208 ha) we are proposing as revised critical habitat 
contains occurrences of Riverside fairy shrimp as well as surrounding 
upland areas (the contributing watershed) that contain the physical and 
biological features essential to support Riverside fairy shrimp where 
they physically occur within the proposed revised critical habitat 
subunits (see Physical and Biological Features below). For specific 
information about how this proposed rule compares to the final critical 
habitat designated for this species in 2005, see the Summary of Changes 
From Previously Designated Critical Habitat section below.

New Information Specific to Riverside Fairy Shrimp

    A study to gather genetic distribution data for Riverside fairy 
shrimp across its range, using mitochondrial DNA (mtDNA) on the 
cytochrome oxidase I (COI) gene, was conducted in 2010 (Lahti et al. 
2010, pp. 1-47). Sequencing of 179 individuals from 32 pools comprising 
20 pool complexes detected low population genetic variability overall 
at the selected locus, and resulted in detection of five unique 
haplotypes (Lahti et al. 2010, p. 17). A haplotype is a combination of 
alleles (the alternative forms of a gene that is located at a specific 
position on a specific chromosome) at a single locus or multiple loci 
that are transmitted together on the same chromosome. This was the 
first study of its kind to look at genetic composition and variation of 
Riverside fairy shrimp across its range and, as such, represents 
preliminary information. Most of the genetic variability was limited to 
San Diego County (Camp Pendleton, San Diego

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north; haplotypes D, E) and Otay Mesa (San Diego south; haplotypes B, 
C), and all pools in Riverside and Orange Counties were fixed for the 
most common haplotype, haplotype A (Lahti et al. 2010, p. 17).
    Although the amount of genetic variation was low, haplotype 
frequencies among complexes varied, showing approximately 60 percent of 
the genetic variability partitioned among pool complexes and 18 percent 
partitioned among regions (Lahti et al. 2010, p. 19). Lahti et al. 
concluded that low variation at the COI gene region does not confer 
definitive evidence that Riverside fairy shrimp populations are 
currently connected by high levels of gene flow rangewide; on the 
contrary in areas where genetic variation was detected, haplotype 
frequencies varied significantly across even geographically proximate 
pools, suggesting low gene flow (Lahti et al. 2010, p. 19). Genetic 
variability and genetic differentiation between and among populations 
(and across the species' distribution) may be important to long-term 
species persistence because it represents the raw material for 
adaptation to differing local conditions and environmental 
stochasticity (Frankham 2005, p. 754). The maintenance of genetic 
variability is crucial to the survival of a species with declining 
populations and a limited range, such as the Riverside fairy shrimp 
(Gilpin and Soul[eacute] 1986, pp. 32-33; Lesica and Allendorf 1995, p. 
756). Loss of genetic connectivity and diversity can hinder a 
population's ability to adapt to ecological perturbations commonly 
associated with urbanization, such as habitat degradation, climatic 
changes, and introduced species (Vandergast et al. 2007, p. 977). 
Vernal pool complexes throughout the range of the Riverside fairy 
shrimp, and within different habitat types, are critical for the 
conservation of this species.

Previous Federal Actions

    The Riverside fairy shrimp was listed as an endangered species on 
August 3, 1993 (58 FR 41384). For a history of Federal actions prior to 
2001, please refer to the September 21, 2000, proposed critical habitat 
rule (65 FR 57136). On May 30, 2001, we published a final rule 
designating critical habitat for the Riverside fairy shrimp (66 FR 
29384). On November 6, 2001, the Building Industry Legal Defense 
Foundation, Foothill/Eastern Transportation Corridor Agency, National 
Association of Home Builders, California Building Industry Association, 
and Building Industry Association of San Diego County filed a lawsuit 
in the United States District Court for the District of Columbia 
challenging the designation of Riverside fairy shrimp critical habitat 
and alleging errors in our promulgation of the May 30, 2001, final 
rule. We requested a voluntary remand, and on October 30, 2002, 
critical habitat for this species was vacated by order of the Federal 
District Court for the District of Columbia and the Service was ordered 
to publish a new final rule with respect to the designation of critical 
habitat for the Riverside fairy shrimp (Building Industry Legal Defense 
Foundation, et al., v. Gale Norton, Secretary of the Interior, et al., 
and Center for Biological Diversity, Inc. and Defenders of Wildlife, 
Inc. Civil Action No. 01-2311 (JDB) (U.S. District Court, District of 
Columbia)).
    On April 27, 2004, we again proposed to designate critical habitat 
for the Riverside fairy shrimp (69 FR 23024). The final critical 
habitat published in the Federal Register on April 12, 2005 (70 FR 
19154). On January 14, 2009, the Center for Biological Diversity filed 
a complaint in the U.S. District Court for the Southern District of 
California challenging our 2005 designation of critical habitat for 
Riverside fairy shrimp (Center for Biological Diversity v. United 
States Fish and Wildlife Service and Dirk Kempthorne, Secretary of the 
Interior, Case No. 3:09-CV-0050-MMA-AJB). A settlement agreement was 
reached with the plaintiffs (Case No. 3:09-cv-00051-JM-JMA; November 
16, 2009) in which we agreed to submit a proposed revised critical 
habitat designation for the Riverside fairy shrimp to the Federal 
Register by May 20, 2011, and submit a final revised critical habitat 
designation to the Federal Register by November 15, 2012.

Critical Habitat

Background

    Critical habitat is defined in section 3 of the Act as:
    (1) The specific areas within the geographical area occupied by the 
species, at the time it is listed in accordance with the Act, on which 
are found those physical or biological features
    (a) Essential to the conservation of the species and
    (b) Which may require special management considerations or 
protection; and
    (2) Specific areas outside the geographical area occupied by a 
species at the time it is listed, upon a determination that such areas 
are essential for the conservation of the species.
    Conservation, as defined under section 3 of the Act, means to use 
and the use of all methods and procedures that are necessary to bring 
any endangered or threatened species to the point at which the measures 
provided pursuant to the Act are no longer necessary. Such methods and 
procedures include, but are not limited to, all activities associated 
with scientific resources management, such as research, census, law 
enforcement, habitat acquisition and maintenance, propagation, live 
trapping, and transplantation, and, in the extraordinary case where 
population pressures within a given ecosystem cannot otherwise be 
relieved, may include regulated taking.
    Critical habitat receives protection under section 7 of the Act 
through the requirement that Federal agencies ensure, in consultation 
with the Service, that any action they authorize, fund, or carry out is 
not likely to result in the destruction or adverse modification of 
critical habitat. The designation of critical habitat does not affect 
land ownership or establish a refuge, wilderness, reserve, preserve, or 
other conservation area. Such designation does not allow the government 
or public to access private lands. Such designation does not require 
implementation of restoration, recovery, or enhancement measures by 
non-Federal landowners. Where a landowner seeks or requests Federal 
agency funding or authorization for an action that may affect a listed 
species or critical habitat, the consultation requirements of section 
7(a)(2) would apply, but even in the event of a destruction or adverse 
modification finding, the obligation of the Federal action agency and 
the landowner is not to restore or recover the species, but to 
implement reasonable and prudent alternatives to avoid destruction or 
adverse modification of critical habitat.
    For inclusion in a critical habitat designation, the habitat within 
the geographical area occupied by the species at the time it was listed 
must contain physical and biological features which are essential to 
the conservation of the species, and it is included only if those 
features may require special management considerations or protection. 
Critical habitat designations identify, to the extent known using the 
best scientific and commercial data available, habitat areas that 
provide essential life-history needs of the species, including but not 
limited to areas which provide for space, food, cover, and protected 
habitat.
    Under the Act, we can designate critical habitat in areas outside 
the

[[Page 31692]]

geographical area occupied by the species at the time it is listed, 
upon a determination that such areas are essential for the conservation 
of the species. We designate critical habitat in areas outside the 
geographical area occupied by a species only when a designation limited 
to its range would be inadequate to ensure the conservation of the 
species. When the best available scientific data do not demonstrate 
that the conservation needs of the species require such additional 
areas, we will not designate critical habitat in areas outside the 
geographical area occupied by the species. An area currently occupied 
by the species but that was not occupied at the time of listing may, 
however, be essential to the conservation of the species and may be 
included in the critical habitat designation.
    Section 4 of the Act requires that we designate critical habitat on 
the basis of the best scientific and commercial data available. 
Further, our Policy on Information Standards Under the Endangered 
Species Act (published in the Federal Register on July 1, 1994 (59 FR 
34271)), the Information Quality Act (section 515 of the Treasury and 
General Government Appropriations Act for Fiscal Year 2001 (Pub. L. 
106-554; H.R. 5658)), and our associated Information Quality Guidelines 
provide criteria, establish procedures, and provide guidance to ensure 
that our decisions are based on the best scientific data available. 
They require our biologists, to the extent consistent with the Act and 
with the use of the best scientific data available, to use primary and 
original sources of information as the basis for recommendations to 
designate critical habitat.
    When we are determining which areas should be designated as revised 
critical habitat, our primary source of information is generally the 
information developed during the listing process for the species. 
Additional information sources include the 1998 Recovery Plan and the 
2008 5-year review for the species, articles in peer-reviewed journals, 
conservation plans developed by States and counties, scientific status 
surveys and studies, biological assessments, or other unpublished 
materials and expert opinion or personal knowledge.
    Habitat and species are often dynamic in that both may shift 
naturally within an area or from one area to another over time. Climate 
change will be a particular challenge for biodiversity because the 
interaction of additional stressors associated with climate change and 
current stressors may push species beyond their ability to survive 
(Lovejoy 2005, pp. 325-326). The synergistic implications of climate 
change and habitat fragmentation are the most threatening facet of 
climate change for biodiversity (Hannah et al. 2005, p. 4). Current 
climate change predictions for terrestrial areas in the Northern 
Hemisphere indicate warmer air temperatures, more intense precipitation 
events, and increased summer continental drying (Field et al. 1999, pp. 
1-3; Hayhoe et al. 2004, p. 12422; Cayan et al. 2005, p. 6; 
Intergovernmental Panel on Climate Change (IPCC) 2007, p. 1181). 
Climate change may lead to increased frequency and duration of severe 
storms and droughts (McLaughlin et al. 2002, p. 6074; Cook et al. 2004, 
p. 1015; Golladay et al. 2004, p. 504). The southwestern region of the 
country is predicted to become drier and hotter overall (Hayhoe et al. 
2004, p. 12424; Seager et al. 2007, p. 1181). Predictions of climatic 
conditions for smaller subregions such as California are less certain.
    Documentation of climate-related changes that have already occurred 
in California (Croke et al. 1998, pp. 2128, 2130; Brashears et al. 
2005, p. 15144), and future drought predictions for California (e.g., 
Field et al. 1999, pp. 8-10; Lenihen et al. 2003, p. 1667; Hayhoe et 
al. 2004, p. 12422; Brashears et al. 2005, p. 15144; Seager et al. 
2007, p. 1181) and North America (IPCC 2007, p. 9), indicate prolonged 
drought and other climate-related changes will continue in the 
foreseeable future. While climate change was not discussed in the 1993 
listing rule, drought was noted in the rule as a stochastic (random or 
unpredictable) event that could have drastic effects on Riverside fairy 
shrimp, given its fragmented and restricted range (58 FR 41384, p. 
41389, August 3, 1993; Service 1998a, p. 34). The magnitude and 
frequency with which local climate-related changes or drought-induced 
impacts may negatively affect limited ephemeral wetland habitats, in 
terms of their seasonal timing, ponding durations, or patterns of 
inundation and dry down, remains untested.
    In southern California, climatic variables affecting vernal pool 
habitats are most influenced by distance from the coast, topography, 
and elevation (Bauder and McMillian 1998, p. 64). As presence and 
persistence of Riverside fairy shrimp appear to be associated with 
precipitation patterns, draw-down factors, and other regional climatic 
factors including aridity (Eriksen and Belk 1999, p. 71), the likely 
impacts of climate change on ecological processes for Riverside fairy 
shrimp are most closely tied to availability and persistence of ponded 
water during the winter and spring. Vernal pools are particularly 
sensitive to slight increases in evaporation or reductions in rainfall 
due to their relative shallowness and seasonality (Field et al. 1999, 
p. 19). Based on existing data, weather conditions in which vernal pool 
flooding promotes hatching, but in which pools become dry (or too warm) 
before embryos are fully developed, are expected to have the greatest 
negative impact on Riverside fairy shrimp resistance and resilience. In 
the 2008 5-year review, we noted that climate change may potentially 
cause changes in vernal pool inundation patterns and pool consistency 
and that drought may decrease or terminate reproductive output if pools 
fail to flood, or if pools dry up before reproduction is complete 
(Service 1998a, p. 34). Long-term or continuing drought conditions may 
deplete cyst banks in affected pools as new reproductive cysts are not 
deposited. Additionally, localized climate-related changes may alter 
the temporal spatial array of occupied habitat patches (across and 
between pool complexes) across the species' geographical range. The 
ability of Riverside fairy shrimp to survive is likely to depend in 
part on their ability to disperse to pools where conditions are 
suitable (Bohonak and Jenkins 2003, p. 786) through passive dispersal 
mechanisms utilizing reproductive cysts (see Life History section 
above).
    The information currently available on the effects of global 
climate change and increasing temperatures does not adequately predict 
the location and magnitude of climate change effects to Riverside fairy 
shrimp; therefore, we are unable to determine if any additional areas 
may be appropriate to include in this proposed revised critical habitat 
designation to address the effects of climate change. We specifically 
request information from the public on the currently predicted effects 
of climate change on Riverside fairy shrimp and its habitat. 
Furthermore, we recognize that designation of critical habitat may not 
include all habitat areas that we may eventually determine are 
necessary for the recovery of the species, based on scientific data not 
now available to the Service. For these reasons, a critical habitat 
designation does not signal that habitat outside the designated area is 
unimportant or may not promote the recovery of the species.
    Areas that support populations of Riverside fairy shrimp, but are 
outside the critical habitat designation, will continue to be subject 
to conservation actions we and other Federal agencies

[[Page 31693]]

implement under section 7(a)(1) of the Act. They are also subject to 
the regulatory protections afforded by the section 7(a)(2) jeopardy 
standard, as determined on the basis of the best available information 
at the time of the agency action. Federally funded or permitted 
projects affecting listed species outside their designated critical 
habitat areas may still result in jeopardy findings in some cases. 
Similarly, critical habitat designations made on the basis of the best 
available information at the time of designation will not control the 
direction and substance of future Recovery Plans, habitat conservation 
plans (HCPs), section 7 consultations, or other species conservation 
planning efforts if new information available to these planning efforts 
calls for a different outcome.

Physical and Biological Features

    In accordance with sections 3(5)(A)(i) and 4(b)(1)(A) of the Act 
and regulations at 50 CFR 424.12, in determining which areas within the 
geographical area occupied at the time of listing to propose as revised 
critical habitat, we consider those physical and biological features 
that are essential to the conservation of the species and which may 
require special management considerations or protection. These include, 
but are not limited to:
    (1) Space for individual and population growth and for normal 
behavior;
    (2) Food, water, air, light, minerals, or other nutritional or 
physiological requirements;
    (3) Cover or shelter;
    (4) Sites for breeding, reproduction, and rearing (or development) 
of offspring; and
    (5) Habitats that are protected from disturbance or are 
representative of the historical, geographical, and ecological 
distributions of a species.
    We derive the specific physical and biological features required 
for Riverside fairy shrimp from studies of this species' habitat, 
ecology, and life history as described below. Additional information 
can be found in the final listing rule published in the Federal 
Register on August 3, 1993 (58 FR 41384), and the 1998 Recovery Plan 
(Service 1998a). We have determined that the Riverside fairy shrimp 
requires physical and biological features described below.
Space for Individual and Population Growth and for Normal Behavior
    Riverside fairy shrimp require vernal pool habitat to grow and 
reproduce. Their life cycle requires periods of inundation as well as 
dry periods (Ripley et al. 2004, pp. 221-223). Habitats (ephemeral 
wetlands) that provide space for growth and persistence of Riverside 
fairy shrimp include areas that generally pond for 2 to 8 months and 
dry down for a period during the late spring to summer months. Habitats 
include natural and manmade pools (usually >12 in (30 cm) deep) which 
support these longer inundation periods; some of these habitats are 
artificial pools (cattle tanks and road embankments) which have been 
modified or deepened with berms (Hathaway and Simovich 1996, p. 670). 
Artificial depressions, often associated with degraded vernal pool 
habitat, are capable of functioning as habitat and can support vernal 
pool species including Riverside fairy shrimp (Moran 1977, p. 155; 
Service 1998a, p. 22). Space for the Riverside fairy shrimp's normal 
growth and behavior requires an underlying soil series (typically clay 
soil inclusions with a subsurface claypan or hardpan component), which 
forms an impermeable layer, that sustains appropriate inundation 
periods (i.e., water only slowly percolates once filled) and provides 
necessary physiological requirements, including but not limited to, 
appropriate water temperature and water chemistry (mineral) regimes, a 
natural prey base, foraging opportunities, and areas for predator 
avoidance.
    Intact vernal pool hydrology (including the seasonal filling and 
drying down of pools) is the essential feature that governs the life 
cycle of the Riverside fairy shrimp. An intact hydrological regime 
includes seasonal hydration (during not all but most years) followed by 
drying out of the substrate to promote overwintering of cysts, and 
provide conditions to support a viable cyst bank for the following 
season. Proper timing of precipitation and the associated hydrological 
and soil processes in the upland watershed contributes to the provision 
of space for growth and normal behavior; seasonal filling and 
persistence of the vernal pool is necessary for cyst hatching and 
successful reproduction of Riverside fairy shrimp (see Sites for 
Breeding, Reproduction, and Rearing (or Development) of Offspring, 
below).
    To maintain high-quality vernal pool ecosystems, the vernal pool 
basin or complex and its upslope vernal pool watershed (adjacent 
vegetation and upland habitat) must be available and functional (Hanes 
and Stromberg 1998, p. 38). Adjacent upland habitat supplies important 
hydrologic inputs to sustain vernal pool ecosystems. Protection of the 
upland habitat between vernal pools within the watershed is essential 
for maintaining space needs for Riverside fairy shrimp (i.e., 
inundation periods of adequate length to support the entire life-
history function and reproductive cycles necessary for Riverside fairy 
shrimp) and to buffer the vernal pools from edge effects.
    Vernal pools generally occur in complexes, which are defined by two 
or more vernal pools in the context of a larger vernal pool watershed. 
The local watershed associated with a vernal pool complex includes all 
surfaces in the surrounding area that flow into the vernal pool 
complex. Within a vernal pool complex, vernal pools are hydrologically 
connected to one another within the local geographical context. These 
vernal pool complexes may connect by either surface, or subsurface, 
flowing water. Pools and complexes are dependent on adjacent 
geomorphology and microtopography for maintenance of their unique 
hydrological conditions (Service 1998a, p. 23). Water may flow over the 
surface from one vernal pool to another (over-fill or ``overbanking''), 
throughout a network of swales, or low-point depressions within a 
watershed. Due to an impervious clay layer or hardpan, water can also 
flow and collect below ground, such that the soil remains saturated 
with water. The result of the movement of the water through vernal pool 
systems is that pools fill and hold water continuously for a number of 
days, to weeks, to months, following the initial rainfall (Hanes et al. 
1990, p. 51). Some hydrologic systems have watersheds that cover a 
large area and that contribute to filling and the hydrological dynamics 
of the system, while other hydrologic systems have very small 
watersheds and fill almost entirely from direct rainfall. It is also 
possible that subsurface inflows from surrounding soils within a 
watershed contribute to filling some vernal pools (Hanes et al. 1990, 
p. 53; Hanes and Stromberg 1998, p. 48).
    Impervious subsurface layers of clay soils or hardpan geology, 
combined with flat to gently sloping topography, serve to inhibit rapid 
infiltration of rainwater, resulting in ponded water in vernal pools 
(Bauder and McMillian 1998, pp. 57-59). These soils also act as a 
buffer to moderate the water chemistry and rate of water loss to 
evaporation (Zedler 1987, pp. 17-30). In Ventura County, soils series 
known to support Riverside fairy shrimp include, but are not limited 
to, the Azule, Calleguas, Cropley, and Linne soil series. In Orange 
County, soils series include the Alo, Balcom, Bosanko, Calleguas, 
Cieneba, Myford, and Soper soil series. In western Riverside County, 
vernal pool habitat known to support Riverside

[[Page 31694]]

fairy shrimp includes the Altamont, Auld, Bosanko, Cajalco, Claypit, 
Murrietta, Porterville, Ramona, Traver, and Willows soil series. In San 
Diego County, vernal pool habitat known to support Riverside fairy 
shrimp includes the Diablo, Huerhuero, Linne, Placentia, Olivenhain, 
Salinas, Stockpen, and Redding soil series. Soil series data are based 
on 2008 Soil Survey Data and are available online at: http://websoilsurvey.nrcs.usda.gov. For additional information on soils, see 
Primary Constituent Elements (PCEs) for Riverside Fairy Shrimp.
Food, Water, Air, Light, Minerals, or Other Nutritional or 
Physiological Requirements
    Riverside fairy shrimp are filter feeders and their diet consists 
mostly of algae, bacteria, and other microorganisms (Parsick 2002, pp. 
37-41, 65-70). In a natural vernal pool setting, these food items are 
readily available. Typically, an undisturbed, intact surface and 
subsurface soil structure (not permanently altered by anthropogenic 
land use activities such as deep, repetitive discing, or grading), and 
the associated hydrogeomorphic processes within the basin and upland 
watershed, are necessary to provide food, water, minerals, and other 
physiological needs for Riverside fairy shrimp. Water temperature, 
water chemistry, and length of time vernal pools are inundated with 
water are the important factors in the hatching and temporal appearance 
of Riverside fairy shrimp (Gonzalez et al. 1996, pp. 315-316; Hathaway 
and Simovich 1996, p. 669). Riverside fairy shrimp hatch and reproduce 
in water at temperatures that range generally from 5 to 20 degrees 
Celsius (C) (41 to 68 degrees Fahrenheit (F)), and typically do not 
hatch at temperatures greater than 25 degrees C (77 degrees F) 
(Hathaway and Simovich 1996, pp. 674-675). Riverside fairy shrimp have 
a wider thermal tolerance than San Diego fairy shrimp (Branchinecta 
sandiegonensis), which allows Riverside fairy shrimp to hatch later in 
the season when deeper vernal pools are still filled with water.
Cover or Shelter
    Ponding of vernal pool habitat (water) also provides cover and 
shelter for Riverside fairy shrimp. During the time these habitats are 
inundated, water plays an important role in providing the necessary 
aquatic environment (shelter) for the fairy shrimp to complete their 
life-history requirements. Without protection from desiccation provided 
by water, fairy shrimp would be unable to hatch, grow, mature, 
reproduce, and disperse within the vernal pool habitat (Helm 1998, p. 
136; Service 1998a, p. 34; Eriksen and Belk 1999, pp. 71, 105). 
Additionally, the wet period (ponding) excludes species that are 
exclusively terrestrial, providing a level of shelter from predation 
and competition for the fairy shrimp that are adapted to short-lived, 
ephemeral wetland habitats.
    The undisturbed soil bank also provides cover and shelter for fairy 
shrimp cysts during the dry-down period of the vernal pool habitat. The 
drying phase allows reproductive cysts to overwinter, as the cysts lay 
dormant in the soil; basin soils provide cover and shelter to Riverside 
fairy shrimp as the vernal pool dries out (Simovich and Hathaway 1997, 
p. 42; Eriksen and Belk 1999, p. 105). By maintaining the population in 
a dormant state, reproductive cysts, and the undisturbed soil in which 
they rest, protect Riverside fairy shrimp from predators and 
competitors during the dry period in vernal pools. Cyst dormancy is an 
important life-history adaptation to surviving arid phases, and is 
important for synchronizing life cycles in unstable and ephemeral 
wetland habitats (Belk and Cole 1975, pp. 209-210). Like the wet period 
exclusion of terrestrial plants, the dry-down period also excludes 
species that are exclusively aquatic (such as fish), providing shelter 
for specially adapted Riverside fairy shrimp.
Sites for Breeding, Reproduction, and Rearing (or Development) of 
Offspring
    Mature shrimp are typically observed from mid-March to April (Eng 
et al. 1990, p. 259). In years with early or late rainfall, the 
hatching period may be extended. Riverside fairy shrimp can reach 
sexual maturity and begin mating approximately 8 weeks from the time a 
vernal pool fills with water (Hathaway and Simovich 1996, p. 673). 
Length of time to maturity presumably restricts Riverside fairy shrimp 
from occupying shallow pools that often last only several days to a few 
weeks (Hathaway and Simovich, p. 674).
    Because vernal pool ecosystems are highly variable in the length of 
time pools remain filled, Riverside fairy shrimp have become adapted to 
some degree of unpredictability in their habitat (Eriksen and Belk 
1999, pp. 104-105) and to a system where the conditions needed for 
success occur transitorily. Depending on rainfall and environmental 
conditions, a vernal pool may fill and recede numerous times. Often the 
pool may evaporate before Riverside fairy shrimp are able to mature and 
reproduce (Ripley et al. 2004, pp. 221-223). Therefore, when the 
females' eggs are fertilized, they begin to develop; the development of 
the fertilized eggs stops at an early stage (after a few cell 
divisions) and the eggs enter diapause (become dormant). Diapausing 
eggs are often referred to as ``cysts'' or ``resting eggs.'' Riverside 
fairy shrimp cysts are small (finer than a tip of a pencil) and contain 
a dormant fairy shrimp embryo encased in a hard outer shell. These 
cysts are generally retained in a brood pouch on the underbelly of the 
female until she dies, when both drop to the bottom of the vernal pool 
to become part of a cyst bank in the soil layer of the vernal pool. 
During subsequent filling events, eggs may emerge from dormancy and 
hatch, or continue to diapause. Signals that break diapause include 
temperature and oxygen concentrations (Belk and Cole 1975, p. 216, see 
Thorp and Covich, p. 767). Resting eggs of freshwater crustaceans have 
been shown to survive drying, heat, freezing, and ingestion by birds 
(Fryer 1996, pp. 1-14). Resting stages (dormancy) appear to be an 
adaptation to temporary habitats and may aid in long-distance dispersal 
(Belk and Cole 1975, pp. 209, 222; Williams 1985, p. 97).
    Researchers have found that only a small portion of the cysts in 
the cyst bank hatch each time the vernal pool fills. As only small 
percentages of Riverside fairy shrimp cysts hatch in any given year, if 
the pool dries before the species is able to mature and reproduce, 
there are still many more cysts left in the soil that may hatch the 
next time the pool fills (Simovich and Hathaway 1997, p. 42). Simovich 
and Hathaway (1997, pp. 40-43) referred to this as ``bet-hedging'' and 
concluded that it allows fairy shrimp, including Riverside fairy 
shrimp, to survive in an unpredictable environment. The ``bet-hedging'' 
ensures that some cysts will be available for hatching when the vernal 
pools hold water for a period long enough for Riverside fairy shrimp to 
complete their entire life cycle. Thus, reproductive output is spread 
over several seasons for small aquatic crustaceans living in variable 
environments. Allowing conditions within the above physical parameters 
to occur on a naturally cyclic basis is essential for the survival and 
conservation of the Riverside fairy shrimp.
    As previously discussed in the Background section above, Riverside 
fairy shrimp are restricted to a small subset of long-lasting vernal 
pools and ephemeral wetlands in southern California because this 
species has a relatively longer maturation rate than other fairy 
shrimp, taking approximately

[[Page 31695]]

8 weeks to reach sexual maturity and begin mating (Hathaway and 
Simovich 1996, p. 673). This distinctly longer maturation rate 
presumably restricts Riverside fairy shrimp typically to pools that are 
moderate to deep vernal pools and ephemeral basins (generally ranging 
from 10 in (25.4 cm) to 5 to 10 feet (1.5 to 3 meters) in depth) 
(Hathaway and Simovich 1996, p. 675).
Habitats That Are Protected From Disturbance or Are Representative of 
the Historical, Geographical, and Ecological Distributions of the 
Species
    The majority of complexes and pools that currently support 
Riverside fairy shrimp have experienced some level of disturbance, some 
more recently or to a greater extent than others. Pools that support 
Riverside fairy shrimp are generally found in flat or moderately 
sloping areas, primarily in annual, disturbed (such as grazed or deep 
disced) grassland and chaparral habitats. These areas are more 
vulnerable to agriculture, cattle, and off-road vehicle activity.
    Estimates of the historical distribution of Riverside fairy shrimp 
suggest that 90 to 97 percent of vernal pool habitat has been lost in 
southern California (Mattoni and Longcore 1997, pp. 71-73, 86-88; 
Bauder and McMillan 1998, p. 66; Keeler-Wolf et al. 1998, p. 10; 
Service 1998a, p. 45). Consideration should be given to conserve much 
of the remaining Riverside fairy shrimp occurrences from further loss 
and degradation in a configuration that maintains habitat function and 
species viability (Service 1998a, p. 62). Historically, there were 
larger complexes of vernal pools including areas on the Los Angeles 
coastal prairie (Mattoni and Longcore 1997, p. 88). In other places, 
such as Riverside County, there is a possibility of documenting 
additional occurrences given more intensive survey efforts and 
reporting. Because Riverside County has not yet been developed and 
fragmented to the same extent as Los Angeles County, we believe 
undocumented occurrences of the Riverside fairy shrimp may occur in 
Riverside County.
    The conservation of Riverside fairy shrimp is dependent on several 
factors including, but not limited to, maintenance of areas (of 
sufficient size and configuration to sustain natural ecosystem 
components, functions, and processes) that provide appropriate 
inundation and ponding durations, natural hydrologic regimes and 
appropriate soils, intermixed wetland and upland watershed, 
connectivity among pools within geographic proximity to facilitate gene 
flow among complexes, and protection of existing vernal pool 
composition and structure.
    In a few locations, two species of fairy shrimp, San Diego fairy 
shrimp and Riverside fairy shrimp, are known to co-occur (Hathaway and 
Simovich 1996, p. 670). However when these species do co-occur, they 
rarely have been observed to coexist as adults (Hathaway and Simovich 
1996, p. 670); given Riverside fairy shrimp's slower rate of 
development, San Diego fairy shrimp are usually found earlier in the 
season than Riverside fairy shrimp (Hathaway and Simovich 1996, p. 
675). Maturation rates are responsible for the sequential appearance of 
the species as adults in pools where they co-occur (Hathaway and 
Simovich 1996, p. 675). Neither species is found in the nearby desert 
or mountain areas, as temperature has been shown to play an important 
role in the spatial and temporal appearance of fairy shrimp.

Primary Constituent Elements (PCEs) for Riverside Fairy Shrimp

    Under the Act and its implementing regulations, we are required to 
identify the physical and biological features essential to the 
conservation of Riverside fairy shrimp in areas occupied at the time of 
listing, focusing on the features' primary constituent elements. We 
consider primary constituent elements to be the elements of physical 
and biological features that are essential to the conservation of the 
species.
    Based on our current knowledge of the physical or biological 
features and habitat characteristics required to sustain the species' 
life-history processes, we determine that the primary constituent 
elements specific to Riverside fairy shrimp are:
    (1) Ephemeral wetland habitat consisting of vernal pools and 
ephemeral habitat that have wet and dry periods appropriate for the 
incubation, maturation, and reproduction of Riverside fairy shrimp in 
all but the driest of years, such that the pools:
    (a) Are inundated (pond) approximately 2 to 8 months during winter 
and spring, typically filled by rain, surface and subsurface flow;
    (b) generally dry down in the late spring to summer months;
    (c) may not pond every year; and
    (d) provide the suitable water chemistry characteristics to support 
Riverside fairy shrimp. These characteristics include physiochemical 
factors such as alkalinity, pH, temperature, dissolved solutes, 
dissolved oxygen, which can vary depending on the amount of recent 
precipitation, evaporation, or oxygen saturation; time of day; season; 
and type and depth of soil and subsurface layers. Vernal pool habitat 
typically exhibits a range of conditions but remains within the 
physiological tolerance of the species. The general ranges of 
conditions include but are not limited to:
    (i) Dilute, freshwater pools with low levels of total dissolved 
solids (low ion levels (sodium ion concentrations generally below 70 
mmol/l);
    (ii) low alkalinity levels (lower than 80 to 1,000 milligrams per 
liter (mg/l)); and
    (iii) a range of pH levels from neutral to alkaline (typically in 
range of 6.4-7.1).
    (2) Intermixed wetland and upland habitats that function as the 
local watershed, including topographic features characterized by 
mounds, swales, and low-lying depressions within a matrix of upland 
habitat that result in intermittently flowing surface and subsurface 
water in swales, drainages, and pools described in PCE 1. Associated 
watersheds provide water to fill the vernal or ephemeral pools in the 
winter and spring months. Associated watersheds vary in size and 
therefore cannot be generalized, and they are affected by factors 
including surface and underground hydrology, the topography of the area 
surrounding the pool or pools, the vegetative coverage, and the soil 
substrates in the area. Size of associated watershed likely varies from 
a few acres to greater than 100 ac (40 ha).
    (3) Soils that support ponding during winter and spring which are 
found in areas characterized in PCEs 1 and 2 that have a clay component 
or other property that creates an impermeable surface or subsurface 
layer. Soil series with a clay component or an impermeable surface or 
subsurface layer typically slow percolation, increase water run-off (at 
least initially), and contribute to the filling and persistence of 
ponding of ephemeral wetland habitat where Riverside fairy shrimp 
occur. Soils and soil series known to support vernal pool habitat 
include, but are not limited to:
    (a) The Azule, Calleguas, Cropley, and Linne soils series in 
Ventura County;
    (b) the Alo, Balcom, Bosanko, Calleguas, Cieneba, and Myford soils 
series in Orange County;
    (c) the Cajalco, Claypit, Murrieta, Porterville, Ramona, Traver, 
and Willows soils series in Riverside County; and
    (d) the Diablo, Huerhuero, Linne, Placentia, Olivenhain, Redding, 
Salinas, and Stockpen soils series in San Diego County.
    This proposed rule identifies the PCEs necessary to support one or 
more of the

[[Page 31696]]

life-history functions of Riverside fairy shrimp and those areas 
containing the PCEs. We believe conservation of the Riverside fairy 
shrimp is dependent upon a multitude of factors. Conservation and 
management of areas across the species' range that maintain normal 
hydrologic and ecological functions where existing populations survive 
and reproduce and that are representative of the geographic 
distribution of the species, conservation of areas representative of 
the ecological distribution of Riverside fairy shrimp (various 
combinations of soil types, vernal pool chemistry, geomorphic surfaces 
and vegetation community associations), and conservation of areas that 
allow for the movement of cysts between areas representative of the 
geographic and ecological distribution of the species (within and 
between vernal pool complexes) are the considered criteria needed for 
the conservation of Riverside fairy shrimp.
    We are proposing to designate most of the known occupied habitat of 
Riverside fairy shrimp because: (1) Riverside fairy shrimp are non-
migratory; (2) disjunct populations likely represent unique, locally 
adapted populations (adapted to unique, site-specific or habitat-
specific environmental conditions); and (3) gene exchange between 
populations or critical habitat units is likely infrequent. Where 
management units are sufficiently distant (16 to 159 mi (26 to 256 km)) 
from one another, the likelihood of gene exchange is reduced. All of 
the areas proposed contain one or more of the PCEs essential for the 
species that may require special management considerations or 
protection. We have also determined that all of the areas we are 
proposing (including Johnson Ranch Created Pools (Subunit 3h) that was 
occupied after the time of listing) are essential to the conservation 
of the species because these areas: (1) Maintain the genetic 
variability of Riverside fairy shrimp across its known geographic range 
and allow for a varying nature and expression of the species, (2) allow 
for gene flow and dispersal, and habitat availability that accommodate 
natural processes of local extirpation and colonization over time (and 
thereby reduce the risk of extinction through random and natural 
events), and (3) maintain a full range of varying habitat types and 
characteristics for a species by encompassing a full extent of the 
physical, biological and environmental conditions essential for the 
conservation of Riverside fairy shrimp.
    Not all life-history functions require all of the PCEs. Therefore, 
not all areas designated as revised critical habitat will contain all 
of the PCEs. All units and subunits proposed to be designated as 
critical habitat are currently occupied (with the exception of Subunit 
1b, which is considered to be occupied by Riverside fairy shrimp) and 
contain one or more primary constituent elements that support the life-
history needs of the species. In the case of this proposed designation, 
most of the units contain all of the PCEs.

Special Management Considerations or Protection

    When designating critical habitat, we first assess whether there 
are specific areas within the geographical area occupied by the species 
at the time of listing that contain features which are essential to the 
conservation of the species and which may require special management 
considerations or protection, before considering whether any areas 
unoccupied at time of listing may be essential to conserve the species. 
Although the determination that special management may be required is 
not a prerequisite to designating critical habitat in areas essential 
for the conservation of the species that are outside the geographical 
area occupied at the time of listing, all areas (units/subunits) we are 
proposing as revised critical habitat in this proposed rule, whether 
occupied or unoccupied at time of listing, require special management 
considerations or protection of the essential features to address 
current and future threats to Riverside fairy shrimp, to maintain or 
enhance the physical and biological features essential to its 
conservation, and to ensure the recovery and survival of the species. 
The areas proposed as revised critical habitat represent our best 
assessment of the habitat that meets the definition of critical habitat 
for Riverside fairy shrimp at this time.
    A detailed discussion of the threats impacting the physical and 
biological features essential to the conservation of Riverside fairy 
shrimp which may require special management considerations or 
protection can be found in the 1991 proposed listing rule (56 FR 57503; 
November 12, 1991), the 1993 final listing rule (58 FR 41384; August 3, 
1993), the 2001 critical habitat designation (66 FR 29384; May 30, 
2001), the 2005 critical habitat designation (70 FR 19154; April 12, 
2005), the 2008 5-year review for Riverside fairy shrimp (Service 2008, 
pp. 12-37), and the 1998 Recovery Plan (Service 1998a, pp. 1-100).
    The physical and biological features in areas proposed as revised 
critical habitat in this proposed critical habitat designation all face 
ongoing threats that require special management considerations or 
protection. Threats which may require special management considerations 
or protection include: vernal pool elimination due to agricultural and 
urban development, including activities associated with construction of 
infrastructure (highways, utilities, water storage, etc.) (PCEs 1, 2, 
3); the construction of physical barriers or impervious surfaces around 
a vernal pool complex (PCEs 1, 2); altered water quality/quantity (PCEs 
1, 2, 3) due to channeling water runoff into a vernal pool complex or 
introduction of water, other liquids, or chemicals (including 
herbicides and pesticides) into the vernal pool basin; physical 
disturbance to the claypan and hardpan soils within the vernal pool 
basin (PCEs 1, 3), including the discharge of dredged or fill material 
into vernal pools and erosion of sediments from fill material; the 
disturbance of soil profile by grading, digging, or other earthmoving 
work within the basin or its upland slopes and/or other activities such 
as off-road vehicle use, heavy foot traffic, grazing, vegetation 
removal, fire management, or road construction within the watershed for 
the vernal pools; the invasion of nonnative plant and animal species 
into the vernal pool basin (PCEs 1, 2), which alter hydrology and soil 
regimes within the vernal pool; and any activity which permanently 
alters the function of the underlying claypan or hardpan soil layer 
(PCE 3) resulting in the disturbance or destruction of the vernal pool 
flora or the associated upland watershed (PCEs 2, 3). All of these 
threats have the potential to permanently reduce or increase: the depth 
of a vernal pool, the ponding duration and inundation of the vernal 
pool, or other vernal pool features beyond the tolerances of Riverside 
fairy shrimp (PCE 1).
    Loss and degradation of wetland habitat, most directly from 
conversion to agriculture and development, was cited in the final 
listing rule as a cause for the decline of Riverside fairy shrimp (58 
FR 41387; August 3, 1993). Most of the populations of this species are 
located in San Diego, Orange, and Riverside Counties. These counties 
have had (and continue to have) increasing human populations and 
attendant housing, development, and infrastructure needs. Natural areas 
in these counties are frequently near or bounded by urbanized areas. 
Grading, discing, and scraping in areas for urbanization results in 
loss of vernal pool topography and soil surface as well as the 
subsurface soil layers to the degree that they will no longer support

[[Page 31697]]

ponding for Riverside fairy shrimp (PCE 3). Urban development modifies 
and removes vernal pool topography, compacts or disturbs soils such 
that basins and upland watershed components are altered, and likely 
eliminates or fragments populations of Riverside fairy shrimp through 
direct crushing of cysts, through disruption of soils and removal of 
the cyst bank, and through the modification of upland hydrology and 
topography, which may potentially isolate a pool or pools within a pool 
complex. Overall, habitat loss continues to be the greatest direct 
threat to Riverside fairy shrimp.
    Because the flora and fauna in vernal pools or swales can change if 
the hydrologic regime is altered (Bauder 1986b), human activities that 
reduce the extent of the watershed or which alter runoff patterns 
(i.e., timing, amount, or flow of water) (PCE 2) may also eliminate 
Riverside fairy shrimp, reduce their population sizes or reproductive 
success, or alter the duration or filling of basins such that the 
location of sites inhabited by this species may shift. Changes to 
hydrologic patterns due to cattle trampling, off-road vehicle use, 
human trampling, road development, military activities, and water 
management activities, impact vernal pools (PCEs 1, 2, 3) (58 FR 41387; 
August 3, 1993). Due to the species highly fragmented and restricted 
range, exacerbation of impacts from habitat fragmentation (species 
isolation) on the species' genetic diversity, patterns of gene flow, 
and persistence; reductions in air and water quality due to human 
urbanization; or changes in nutrient availability associated with 
altered hydrology (Bauder 1986b, pp. 209-211) may further impact vernal 
pool habitats. Unpredictable natural events, such as drought or fire 
can be especially devastating due to the fragmented and restricted 
range of the species (58 FR41390, August 3, 1993). These threats may 
require special management considerations or protection.
    Changes in hydrology that affect the Riverside fairy shrimp's 
primary constituent elements are caused by activities that alter the 
surrounding topography or change historical water flow patterns in the 
watershed (PCEs 2, 3). Even slight alterations of the hydrology can 
change the depth, volume, and duration of ponding inundation; water 
temperature; soil; mineral and organic matter transport to the pool; 
and water quality and chemistry, which in turn can make the ephemeral 
wetland habitat (basin) (PCE 1) unsuitable for Riverside fairy shrimp. 
Activities that impact the hydrology include, but are not limited to, 
road building, grading and earth moving, impounding natural water 
flows, and draining of the pool(s) or of their immediately surrounding 
upland watershed. Impacts to the hydrology of vernal pools can be 
managed through avoidance of such activities in and around the pools 
and the associated surrounding upland areas.
    Disturbance to the impermeable substrate layer of claypan and 
hardpan soils within vernal pools occupied by the Riverside fairy 
shrimp (PCE 3) may alter the depth, ponding inundation, water 
temperature, and water chemistry. Physical disturbances to claypan and 
hardpan soils may be caused by excavation of borrow material, off-road 
vehicles, military training activities, repeated or deep agricultural 
discing, drilling, or creation of berms that obstruct the natural 
hydrological surface or sub-surface flow of water run-off and 
precipitation. Impacts to the soils of vernal pools can be managed 
through avoidance of these activities in and around the pools and the 
associated surrounding upland areas.
    Invasive plant species may alter the ponding inundation and water 
temperature by changing the evaporation rate and shading of standing 
water in vernal pools (PCEs 1, 2, 3). Invasive plant species, such as 
brass-buttons (Cotula coronopifolia) and Pacific bentgrass (Agrostis 
avenaceae), compete with native vernal plant species and may alter the 
physiochemical factors of the water (PCE 1), the ponding duration (PCE 
1), and the upland habitat (PCE 2), and may modify the soils (PCE 3) in 
these vernal pools. Impacts due to invasive plants can be managed such 
that activities needed to remove and manage native vernal pool plants, 
are conducted to maintain the appropriate hydrology and physiochemical 
nature of the vernal pools required by the life-history processes of 
Riverside fairy shrimp.
    Further discussion of specific threats facing individual proposed 
revised critical habitat units is provided in the unit descriptions 
below. In these proposed revised critical habitat units, special 
management considerations or protection may be needed to ensure the 
long-term existence and management of ephemeral and upland habitat 
sufficient for the shrimp's successful reproduction and growth, 
adequate feeding habitat, and proper physiochemical and environmental 
regimes, linked hydrology, and connectivity within the landscape.

Criteria Used To Identify Critical Habitat

    As required by section 4(b)(1)(A) of the Act, we use the best 
scientific and commercial data available in determining areas within 
the geographical area occupied at the time of listing that contain the 
features essential to the conservation of the Riverside fairy shrimp, 
and areas outside of the geographical area occupied at the time of 
listing that are essential for the conservation of the Riverside fairy 
shrimp. We reviewed available information pertaining to the habitat 
requirements of the species. In accordance with the Act and its 
implementing regulations at 50 CFR 424.12(e), we considered whether 
designating additional areas outside those areas occupied at the time 
of listing are essential to ensure the conservation of the species. We 
are proposing designation of critical habitat in areas within the 
geographical area occupied by the species at the time of listing in 
1993 with features essential to conservation of the species that may 
require special management considerations and protection. We are also 
proposing designation of the the Johnson Ranch Created Pools area. 
Although this area was not occupied at the time of listing, we believe 
the area is also essential for the conservation of the the Riverside 
fairy shrimp, considering the very restricted distribution of the 
species. We believe the long-term conservation of Riverside fairy 
shrimp depends upon the ongoing protection and management of these 
remaining, occupied vernal pools within the known range of the species.
    During preparation of the 1998 Recovery Plan for Vernal Pools in 
Southern California (see further explanation below), we evaluated the 
data on known Riverside fairy shrimp occurrences and determined, based 
on the features associated with vernal pools and vernal pool complexes, 
those necessary for the stabilization and reclassification of the 
species (Service 1998a, Appendices F, G). We since have reevaluated 
those areas based on species occupancy, and their hydrology, watershed, 
and topographic features, and their current management needs. Lands are 
proposed for designation (with the exception of Subunit 3g) based on 
sufficient PCEs being present to support the species' life-history 
processes.
    In determining which areas of habitat occupied at time of listing 
currently contain the physical and biological features essential to the 
conservation of Riverside fairy shrimp, we used all

[[Page 31698]]

available scientific and commercial data including information from the 
1991 proposed listing rule (56 FR 57503; November 12, 1991); the 1993 
final listing rule (58 FR 41384; August 3, 1993); the 2004 proposed 
critical habitat designation for Riverside fairy shrimp (69 FR 23024; 
April 27, 2004); the 2005 final critical habitat designation (70 FR 
19154; April 12, 2005); the 1998 Recovery Plan (Service 1998a, pp. 1-
113); the 2008 5-year review for Riverside fairy shrimp (Service 2008, 
pp. 1-57); the California Department of Fish and Game's (CDFG) 
California Natural Diversity Database (CNDDB) records; published peer-
reviewed articles; unpublished papers and reports; academic theses; 
survey results; Geographic Information System (GIS) data (such as 
species occurrences, soil data, land use, topography, and ownership 
maps); and correspondence to the Service from recognized experts. We 
solicited new information collected since publication of the 1998 
Recovery Plan and 2005 final critical habitat designation, including 
information from State, Federal, and tribal governments; scientific 
data on Riverside fairy shrimp collected by academia and private 
organizations; information in reports submitted during consultations 
under section 7 of the Act; information contained in analyses for 
individual and regional HCPs where Riverside fairy shrimp is a covered 
species; and data collected from reports submitted by researchers 
holding recovery permits under section 10(a)(1)(A) of the Act.
    At the time Riverside fairy shrimp was listed in 1993, the 
geographical area occupied by the species was considered to include 
Orange, Riverside, and San Diego Counties, as well as Baja, Mexico (58 
FR 41384; August 3, 1993). We now have additional records of occurrence 
for Riverside fairy shrimp extending the species' distribution; we 
believe these additional areas were occupied at the time of listing but 
were not identified at the time of listing or in the Recovery Plan.
    Although not explicitly detailed, the Recovery Plan identifies 
areas essential to the recovery of the species as those that are 
determined necessary to advance at least one of the following 
conservation criteria: (1) Maintain habitat function and spatial 
configuration for species viability in the long term; (2) support 
stable, intact occurrences; (3) represent unique habitat or habitat 
associations within the species' range; and (4) capture the ecological, 
biological, edaphic (soils), micro-topography, genetic, and 
geographical variation within vernal pools and vernal pool complexes 
throughout the species' range.
    Our determination of habitat essential to the conservation of 
Riverside fairy shrimp takes into consideration this generalized 
conservation approach and areas identified in the 1998 Recovery Plan as 
necessary for the species stabilization and reclassification. The 1998 
Recovery Plan identifies ``management areas'' on which the long-term 
conservation and recovery of Riverside fairy shrimp depends. Appendices 
F and G in the 1998 Recovery Plan defined known vernal pool complexes 
essential to the conservation of several vernal pool species, including 
Riverside fairy shrimp (Service 1998a, pp. F1-G3). Eight distinct 
management areas were identified based on plant and animal 
distribution, soil types, and climatic variables (Service 1998a, pp. 
38-39). Management areas include vernal pools and complexes known to be 
occupied and essential to the conservation of Riverside fairy shrimp.
    The 1998 Recovery Plan uses management areas to define regional 
conservation objectives. We have used these same management areas and 
names to assist us in identifying specific areas essential to the 
conservation of the Riverside fairy shrimp where possible. In cases 
when new occurrence data identifies occupied vernal pools not 
identified in the Recovery Plan, we have relied on the best available 
scientific data to update map coverages (for example, in Orange and 
Riverside Counties). We believe these new occurrences were in fact 
occupied at the time of listing, but only have been documented since 
the publication of the recovery plan. Our 2005 final rule to designate 
critical habitat used locations identified in Appendices F and G of the 
1998 Recovery Plan; however, for this proposed revised critical habitat 
(due to improvements to the PCEs and mapping methodologies), some 
additions and subtractions have occurred in areas previously identified 
as essential either in the 1998 Recovery Plan or in the 2005 final 
critical habitat designation (Table 1). In some cases, areas within 
subunits have been reduced because they simply do not contain the PCEs 
essential to the conservation of the Riverside fairy shrimp. In other 
cases, we have new distribution information which has led us to remove 
areas previously determined as essential because the physical and 
biological features do not support the necessary PCEs, such that we no 
longer believe that they meet the definition of essential to the 
conservation of the species (i.e., are areas which have been 
significantly altered or impacted since the 2005 designation). Specific 
differences from the 2005 final rule are summarized in the Summary of 
Changes from Previously Designated Critical Habitat section of this 
rule.

 Table 1--Areas Identified as Necessary for Stabilizing Riverside Fairy Shrimp Populations as Listed in Appendix
   F of 1998 Recovery Plan, as Identified as Essential in the 2005 Final Critical Habitat Designation, and as
               Identified as Essential in This 2011 Proposed Revised Critical Habitat Designation
----------------------------------------------------------------------------------------------------------------
                                                                  2005 Final critical    2011  Proposed  revised
            Name/location               Listed in  Appendix F        habitat (fCH)           critical habitat
                                       of 1998  Recovery Plan    designation (subunit)       (prCH) (subunit)
----------------------------------------------------------------------------------------------------------------
                                Unit 1: Ventura County (Goleta and Transverse MA)
----------------------------------------------------------------------------------------------------------------
Tierra Rejada Preserve (*RP:          Yes.....................  1a.....................  1a.
 Carlsberg (Ranch)).
South of Tierra Rejada Valley (east   No......................  1b.....................  1b.
 of Hwy 23).
Cruzan Mesa (*RP: Cruzan Mesa)......  Yes.....................  1c; Removed............  Not proposed.
----------------------------------------------------------------------------------------------------------------
                Unit 2: Los Angeles Basin-Orange County Foothills (Los Angeles Basin--Orange MA)
----------------------------------------------------------------------------------------------------------------
(MCAS) El Toro (*RP: El Toro).......  Yes.....................  2c; 4(b)(2) exclusion..  2c.

[[Page 31699]]

 
SCE Viejo Conservation Bank.........  No......................  No subunit ;    2i.
                                                                 4(b)(2) exclusion.
Saddleback Meadow (*RP: Saddleback    Yes #...................  2d; 4(b)(2) exclusion..  2dA.
 Meadow).
O'Neill Regional Park--near Trabuco   Yes #...................  2d; 4(b)(2) exclusion..  2dB.
 Canyon.
O'Neill Regional Park--near           Yes #...................  2......................  2e.
 Ca[ntilde]ada Gobernadora/east of
 Tijeras Creek.
Chiquita Ridge (*RP: Chiquita Ridge)  Yes.....................  2f; 4(b)(2) exclusion..  2f.
``RP: Orange County Foothills         Yes #...................  .......................  Proposed as subunits
 (undescribed)''.                                                                         herein (2dB, 2e, 2g,
                                                                                          2h, 2i).
Radio Tower Road....................  No......................  2g; 4(b)(2) exclusion..  2g.
San Onofre State Beach, State Park-   No......................  2h; 4(a)(3) exemption..  2h.
 leased land (near Christianitos
 Creek foothills).
----------------------------------------------------------------------------------------------------------------
                                 Unit 3: Riverside Inland Valleys (Riverside MA)
----------------------------------------------------------------------------------------------------------------
March Air Reserve Base..............  No......................  3a; Removed............  Not proposed.
March Air Reserve Base..............  No......................  3b; 4(a)(3) exemption..  Not proposed.
Australia Pool......................  No......................  No subunit ;    3c.
                                                                 4(b)(2) exclusion.
Scott Road Pool.....................  No......................  No subunit ;    3d.
                                                                 4(b)(2) exclusion.
Schleuniger Pool....................  No......................  No subunit ;    3e.
                                                                 4(b)(2) exclusion.
Skunk Hollow and Field Pool (aka      Yes.....................  No subunit ;    3f.
 Barry Jones Wetland Mitigation                                  4(b)(2) exclusion.
 Bank) (*RP: Skunk Hollow/Murrieta).
Johnson Ranch Created Pool..........  No......................  No subunit ;    3g.
                                                                 4(b)(2) exclusion.
Santa Rosa Plateau--Mesa de Colorado  Yes.....................  Not proposed...........  3h.
 (*RP: Santa Rosa Plateau).
----------------------------------------------------------------------------------------------------------------
    No Unit : Northern San Diego County Military Land, Exempted (San Diego North Coastal Mesa MA)
----------------------------------------------------------------------------------------------------------------
Stuart Mesa, Marine Corps Base (MCB)  Yes.....................  No subunit ;    4(a)(3)(B) exemption.
 Camp Pendleton (*RP: Stuart Mesa).                              4(a)(3)(B) exemption.
Cockleburr, MCB Camp Pendleton (*RP:  Yes.....................  No subunit ;    4(a)(3)(B) exemption.
 Cockleburr ).                                                   4(a)(3)(B) exemption.
Las Pulgas, MCB Camp Pendleton (*RP:  Yes.....................  No subunit ;    4(a)(3)(B) exemption.
 Las Pulgas).                                                    4(a)(3)(B) exemption.
Land south of San Onofre State Park.  Yes.....................  No subunit ;    4(a)(3)(B) exemption.
                                                                 4(b)(2) exclusion for
                                                                 Mission Critical.
San Mateo, MCB Camp Pendleton (*RP:   Yes.....................  No subunit ;    Not proposed.
 San Mateo).                                                     4(a)(3)(B) exemption.
Wire Mountain, MCB Camp Pendleton     Yes.....................  4(a)(3)(B) exemption...  Not proposed.
 (*RP: Wire Mountain).
Portion of San Onofre State Beach,    No......................  No subunit ;    4(a)(3)(B) exemption.
 State Park-leased land near                                     4(b)(2) exclusion for
 Christianitos Creek foothills)                                  National Security.
 (*RP: State Park Lease Area).
----------------------------------------------------------------------------------------------------------------
  No Unit : Central Sand Diego County, Military Land, Exempted--(San Diego Central Coastal Mesa MA)
----------------------------------------------------------------------------------------------------------------
AA 1-7, 9-13 East Miramar (Pool 10)   Yes.....................  4(a)(3)(B) exemption...  4(a)(3)(B) exemption.
 (AA1 East).
----------------------------------------------------------------------------------------------------------------
                       Unit 4: San Diego North Coastal Mesas (San Diego: North Coastal MA)
----------------------------------------------------------------------------------------------------------------
Poinsettia Lane Commuter Train        Yes.....................  4c.....................  4.
 Station (JJ 2) (*RP: JJ 2
 Poinsettia Lane).
----------------------------------------------------------------------------------------------------------------
                     Unit 5: San Diego Southern Coastal Mesas (San Diego: South Coastal MA)
----------------------------------------------------------------------------------------------------------------
J 33 (Sweetwater High School).......  No......................  5a; 4(b)(2) exclusion..  5a.
J 15 Arnie's Point (*RP: J2, J5, J7,  Yes#....................  5b; 4(b)(2) exclusion..  5b.
 J11-21, J23-30).
East Otay Mesa (*RP: Otay Mesa        Yes.....................  5c; partial 4(b)(2)      5c.
 undescribed).                                                   exclusion.
``Otay Mesa vernal pool complexes''   Yes#....................  No subunit ;    Proposed as subunits
 (*RP: J2, J5, J7, J11-21, J23-30).                              4(b)(2) exclusion.       below.
J29-31 (*RP: J2, J5, J7, J11-21, J23- Yes#....................  No subunit ;    5d.
 30).                                                            4(b)(2) exclusion.

[[Page 31700]]

 
J2 N, J4, J5 (Robinhood Ridge--J2)    Yes.....................  No subunit ;    5e.
 (*RP: J2, J5, J7, J11-21, J23-30).                              4(b)(2) exclusion.
J2 S and J2 W (aka Hidden Valley,     Yes.....................  No subunit ;    5f.
 Cal Terraces, Otay Mesa Road) (*RP:                             4(b)(2) exclusion.
 J2, J5, J7, J11-21, J23-30).
J14.................................  No......................  No subunit ;    5g.
                                                                 4(b)(2) exclusion.
J11-12, J16-19 (Goat Mesa) (*RP: J2,  Yes.....................  No subunit ;    5h.
 J5, J7, J11-21, J23-30).                                        4(b)(2) exclusion.
----------------------------------------------------------------------------------------------------------------
MA: Management Area as defined in 1998 Recovery Plan.
(*RP): Indicates the name of pool (or pool complex) as stated in the 1998 Recovery Plan.
No: not in 1998 Recovery Plan; occurrence not identified until after 1998.
Yes: indicates the location was identified in the 1998 Recovery Plan.
Yes#: indicates the location was considered in the 1998 Recovery Plan, but at that time was grouped (``lumped'')
  as multiple vernal pool complexes. These locations have now been ``unlumped'' in this 2011 proposed rule.

    We consider all areas proposed as revised critical habitat to have 
been occupied at the time of listing (with the exception of Johnson 
Ranch Created Pools--Subunit 3g, which was not occupied at the time of 
listing). As further discussed in the unit descriptions below, all 
areas proposed as critical habitat for Riverside fairy shrimp are 
currently occupied by the species (Subunit 1b is considered occupied--
see unit description below), are within the species' geographical 
range, and contain PCEs to support at least one of its life-history 
functions. If protocol surveys fail to confirm occupancy of Subunit 1b, 
we are also proposing to designate this area under Section 3(5)(A)(ii) 
of the Act because we have determined the area is essential for the 
conservation of the Riverside fairy shrimp (see Subunit 1b unit 
description below).
    As noted above, we also are proposing designation of an area not 
occupied by the species at the time of listing but which is currently 
occupied (3g; Johnson Ranch Created Pools), because we have determined 
the area is essential for the conservation of the species (see unit 
description below).
    We are proposing critical habitat in specific areas that include 
ephemeral wetland habitat and intermixed wetland and upland habitats of 
various sizes that possess appropriate soils and topography that 
support ponding during winter and spring; are within the known 
geographical and elevation range of Riverside fairy shrimp; are 
geographically distributed; represent unique ecological or biological 
features and associations; and will help protect against stochastic 
extirpation, allow for local adaptation, and provide connectivity to 
facilitate dispersal and genetic exchange. By protecting a variety of 
habitats throughout the species' historical range, we increase the 
probability that the species can adjust in the future to various 
limiting factors that may affect the population, such as changes in 
abundance and timing of precipitation.
    As required by section 4(b)(1)(A) of the Act, we used the best 
scientific data available in determining areas that contain the 
features that are essential to the conservation of Riverside fairy 
shrimp. The steps we followed in identifying critical habitat are 
described in detail below.
    (1) We determined, in accordance with section 3(5)(A)(i) of the Act 
and regulations at 50 CFR 424.12, the physical and biological habitat 
features that are essential to the conservation of the species (see 
Physical and Biological Features section above).
    (2) We compiled all available observational data on Riverside fairy 
shrimp into a GIS database. Data on locations of Riverside fairy shrimp 
occurrences are based on collections and observations made by 
biologists, biological consultants, and academic researchers. We 
compiled data from the following sources to create our GIS database for 
Riverside fairy shrimp: (a) Data used in the 1998 Recovery Plan, in the 
2005 final critical habitat rule for Riverside fairy shrimp, and in the 
2008 5-year review for Riverside fairy shrimp; (b) the CNDDB data 
report for Riverside fairy shrimp and accompanying GIS records (CNDDB 
2010, pp. 1-9); (c) data presented in the City of San Diego's Vernal 
Pool Inventory for 2002-2003 (City of San Diego 2004, pp. 1-125); (d) 
monitoring reports for Riverside fairy shrimp from MCB Camp Pendleton 
and MCAS Miramar; (e) the Western Riverside County MSHCP species GIS 
database; and (f) the Carlsbad Fish and Wildlife Office's (CFWO) 
internal species GIS database, which includes the species data used for 
the County of San Diego MSCP and Western Riverside County MHCP, reports 
from section 7 consultations, and Service observations of Riverside 
fairy shrimp (CFWO internal species GIS database).
    Compiled data were reviewed to ensure accuracy. Each data point in 
our database was checked to ensure that it represented an original 
collection or observation of Riverside fairy shrimp and that it was 
mapped in the correct location. Data points that did not match the 
description for the original collection or observation were remapped in 
the correct location or removed from our database.
    (3) We determined which occurrences were extant at the time of 
listing based on the listing rule as well as information that has 
become available since listing. We considered several sources in 
compiling the best available data on Riverside fairy shrimp vernal pool 
distribution and species occurrence; we have concluded that, with the 
exception of Johnson Ranch Created Pools (Subunit 3g), all currently 
occupied vernal pools were also occupied and extant at the time of 
listing (see Background section, and the specific unit descriptions 
below). We have drawn this conclusion because Riverside fairy shrimp 
has limited dispersal capabilities, and because surveys for the species 
at the time of listing were incomplete. We believe that the 
documentation of additional occurrences within the range of the

[[Page 31701]]

species after the species was listed was due to an increased effort to 
survey for this species. Therefore, we believe that all of the areas 
currently extant, excepting Johnson Ranch Created Pools which were 
created using cysts salvaged from a nearby historic occurrence (at 
Redhawk development), were occupied prior to the time this species was 
listed.
    (4) We identified which areas contain the PCEs and identified which 
of those areas may require special management considerations or 
protection. All areas containing PCEs were mapped and areas not 
containing PCEs were removed. Units were designated based on sufficient 
PCEs being present to support Riverside fairy shrimp life-history 
processes. Some units contain all of the identified PCEs and support 
multiple life stages (resting cyst, nauplii, adult). Some units contain 
only some of the PCEs necessary to support adult Riverside fairy 
shrimp. Areas that we have identified as having one or more PCEs: (a) 
Contain large, interconnected ephemeral wetlands; have large numbers of 
individuals observed; or have habitat areas that allow for connections 
between existing occurrences of Riverside fairy shrimp; (b) represent 
important occurrences of this species that are on the geographic edge 
of this species' distribution; (c) contain occurrences that are more 
isolated from other occurrences by geographic features, but may 
represent unique adaptations to local features (biogeochemistry, 
hydrology, microclimate, soil mineralogy, soil fertility, soil 
formation processes, and evolutionary time scale); or (d) exist within 
the distribution of this species and provide connections between 
occupied areas. The conservation of stable and persistent occurrences 
throughout the species' range helps to maintain connectivity between 
occurrences that are in proximity to one another and maintain potential 
gene flow.
    (5) We circumscribed boundaries of potential critical habitat, 
based on information obtained from the above steps. To map areas 
proposed as revised critical habitat, we used data on known Riverside 
fairy shrimp locations and those vernal pools and vernal pool complexes 
that we identified in the 1998 Recovery Plan as essential for the 
stabilization and reclassification of the species. For areas identified 
as essential, we mapped the specific areas that contain the physical 
and biological features needed to support life-history functions for 
Riverside fairy shrimp (PCEs). We took the following actions: We first 
mapped the ephemeral wetland habitat in the occupied area using 
occurrence data, aerial imagery, and 1:24,000 topographic maps. We then 
mapped the intermixed wetland and upland habitats that function as the 
local watersheds and the topography and soils that support the occupied 
ephemeral wetland habitat. We mapped these areas to identify the gently 
sloping area associated with ephemeral wetland habitat and any adjacent 
areas that slope directly into the ephemeral wetland habitat, which 
contribute to the hydrology of the ephemeral wetland habitat. We 
delineated the border of the proposed revised critical habitat around 
the occupied ephemeral wetlands and associated local watershed areas to 
follow natural breaks in the terrain such as ridgelines, mesa edges, 
and steep canyon slopes.
    (6) Once all areas containing the PCEs were mapped, we removed all 
areas not containing the physical and biological features essential to 
the conservation of Riverside fairy shrimp. For example, when 
determining proposed critical habitat boundaries, we made every effort 
to avoid including developed areas such as lands covered by buildings, 
pavement, and other structures because such lands lack physical and 
biological features for Riverside fairy shrimp. The scale of the maps 
we prepared under the parameters for publication within the Code of 
Federal Regulations may not reflect the exclusion of such developed 
lands. Any such lands inadvertently left inside critical habitat 
boundaries shown on the maps of this proposed rule have been excluded 
by text in the proposed rule and are not proposed for designation as 
critical habitat. Therefore, if the critical habitat is finalized as 
proposed, a Federal action involving these lands would not trigger 
section 7 consultation with respect to critical habitat and the 
requirement of no adverse modification unless the specific action would 
affect the physical and biological features in any adjacent critical 
habitat.
    (7) We also exempted areas within the boundaries of MCB Camp 
Pendleton and MCAS Miramar for this proposed rule because we determined 
these areas are exempt under section 4(a)(3)(B)(i) of the Act from 
critical habitat designation (see Exemptions section below).
    We are proposing for designation as revised critical habitat lands 
that we have determined were occupied at the time of listing and are 
currently occupied and contain physical and biological features that 
are essential to the conservation of the species because they support 
Riverside fairy shrimp life-history processes, and one area that was 
not occupied at the time of listing (Johnson Ranch Created Pools) that 
we have determined is essential for the conservation of Riverside fairy 
shrimp.

Summary of Changes From Previously Designated Critical Habitat

    The areas identified in this proposed rule constitute a proposed 
revision of the areas we designated as critical habitat for Riverside 
fairy shrimp on April 12, 2005 (70 FR 19154). In cases where we have 
new information or information that was not available for the previous 
designation, we made changes to the critical habitat for Riverside 
fairy shrimp to ensure that this proposed rule reflects the best 
scientific data available.
    We made a number of changes to this proposed rule compared to the 
2005 final critical habitat designation, including the following:
    (1) We refined the Primary Constituent Elements (PCEs) to 
specifically capture those physical and biological features essential 
to the conservation of Riverside fairy shrimp, and to more accurately 
describe a range of physiochemical factors (e.g., dissolved solutes, 
temperature, and other water chemistry attributes) that are necessary 
for completion of Riverside fairy shrimp's essential life-history 
processes.
    (2) We incorporated information related to the genetics of the 
species rangewide and new distribution data that have become available 
to us following the 2005 critical habitat designation.
    (3) We renamed unit and subunit numbers, and when appropriate 
redefined (redrew) boundaries to improve and better delineate those 
areas containing features essential to the survival and conservation of 
Riverside fairy shrimp. Boundaries more precisely capture the 
underlying physical and biological features associated with vernal 
pools and vernal pool complexes throughout the species' range. In the 
2005 rule, we used 330-ft (100-m) Universal Transverse Mercator (UTM) 
(North American Datum 1927 (NAD 27)) grid cells overlaid on top of 
those vernal pool complexes and their associated watershed. In this 
proposed revision, because we have improved our mapping methodology and 
our selection criteria, areas containing upland habitat not directly 
contributing to the hydrology of the vernal pools have not been 
included in this proposal.
    (4) We re-evaluated areas considered for exclusion from critical 
habitat designation under section 4(b)(2) of the Act for which we are 
seeking public comment (see Public Comments section of this rule).

[[Page 31702]]

    (5) We added, subtracted, and revised areas that do or do not meet 
the definition of critical habitat. Certain areas identified as 
previously meeting the definition of critical habitat were determined--
based on a review of the best available scientific and commercial 
information--to no longer meet the definition of critical habitat. In 
these cases, we removed areas that no longer meet the definition of 
critical habitat due to significant alterations in drainage or 
development within the watershed. The revised criteria resulted in 
inclusion of areas essential to the conservation of the species and 
removal of areas (since the 2004 proposed rule or the 2005 final rule) 
that no longer meet the definition of critical habitat.
    In this proposed revised critical habitat, we have identified 33 
areas that we believe meet the definition of critical habitat. One of 
the areas being proposed was unoccupied at the time of listing (Johnson 
Ranch Created Pools). Each of the 33 areas contains the physical and 
biological features essential to the conservation of Riverside fairy 
shrimp. Table 2 shows a comparison of the locations, units, and acreage 
between the 2005 final critical habitat designation and this proposed 
revised critical habitat designation. Eight of the 33 areas determined 
to be essential are in north San Diego County on MCB Camp Pendleton and 
are exempt from this proposed rule under section 4(a)(3)(B)(i) of the 
Act: San Onofre State Beach, State Park-leased lands, near 
Christianitos Creek foothills (along the northwest corner of MCB Camp 
Pendleton); area south of San Onofre State Beach, in Uniform Training 
Area; Las Pulgas North; Las Pulgas East; Las Pulgas West; Cockleburr 
North; Cockleburr South; and Stuart Mesa; One area is on MCAS Miramar 
(AA1) and is also exempt from this proposed rule under section 
4(a)(3)(B) of the Act. The remaining 25 areas (5 units consisting of 25 
subunits) that meet the definition of critical habitat are mapped as 
proposed revised critical habitat for Riverside fairy shrimp, are 
presented in Table 2, and are described in the unit descriptions below.

  Table 2--Evaluation of Units and Subunits for Areas Containing Essential Features Between 2005 Final Critical
  Habitat (fCH) and 2011 Proposed Revised Critical Habitat (prCH Considered To Meet the Definition of Critical
                                                     Habitat
 [Note: If amount in 2005 final critical habitat is bracketed, the unit/subunit and its acreage were proposed in
                                           2004 but removed in 2005.]
----------------------------------------------------------------------------------------------------------------
                                   2005 Final critical habitat [or prCH   2011 Proposed revised critical habitat
                                                   2004]                 ---------------------------------------
                                 ----------------------------------------
            Location*                                   Area containing                         Area containing
                                        Subunit       essential features        Subunit       essential features
                                                             2005                                    2011
----------------------------------------------------------------------------------------------------------------
                                     Unit 1: Ventura County Management Area
----------------------------------------------------------------------------------------------------------------
Tierra Rejada Preserve..........  1a................  47 ac (19 ha).....  1a................  18 ac (7 ha).
----------------------------------------------------------------------------------------------------------------
South of Tierra Rejada Valley...  1b................  185 ac (75 ha)....  1b................  448 ac (182 ha).
Cruzan Mesa.....................  [1c; 534 ac (216    0 ac (0 ha).......  1c; no longer       0 ac (0 ha).
                                   ha)]; Removed.                          meets definition
                                                                           of essential; no
                                                                           confirmed species
                                                                           occupancy data.
----------------------------------------------------------------------------------------------------------------
                        Unit 2: Los Angeles Basin-Orange County Foothills Management Area
----------------------------------------------------------------------------------------------------------------
LAX.............................  [2a; 49 ac (20      0 ac (0 ha).......  2a; no longer       0 ac (0 ha).
                                   ha)]; Removed.                          meets definition
                                                                           of essential;
                                                                           PCEs no longer
                                                                           present.
----------------------------------------------------------------------------------------------------------------
LAX.............................  [2b; 54 ac (22      0 ac (0 ha).......  2b; no longer       0 ac (0 ha).
                                   ha)]; Removed.                          meets definition
                                                                           of essential;
                                                                           PCEs no longer
                                                                           present.
(MCAS) El Toro..................  [2c; Excluded       14 ac (6 ha)......  2c................  26 ac (11 ha).
                                   under section
                                   4(b)(2)].
SCE Viejo Conservation Bank.....  Excluded under      84 ac (34 ha).....  2i................  63 ac (25 ha).
                                   section 4(b)(2).
Saddleback Meadows and O'Neill    Unit 2 combined;    57 ac (23 ha)       2dA...............  256 ac (104 ha).
 Regional Park--near Trabuco       portion excluded    Excluded.
 Canyon.                           under section
                                   4(b)(2).
                                  ..................  49 ac (20 ha).....  2dB...............  91 ac (37 ha).
O'Neill Regional Park--near       Excluded under      101 ac (41 ha)....  2e................  70 ac (28 ha).
 Canada Gobernadora/east of        section 4(b)(2).
 Tijeras Creek.
Chiquita Ridge..................  Excluded under      262 ac (106 ha)...  2f................  56 ac (23 ha).
                                   section 4(b)(2).
Radio Tower Road................  Excluded under      417 ac (169 ha)...  2g................  51 ac (21 ha).
                                   section 4(b)(2).
San Onofre State Beach, State     Excluded under      47 ac (19 ha).....  2h................  107ac (43 ha).
 Park-leased lands.                section 4(b)(2).
----------------------------------------------------------------------------------------------------------------
                                Unit 3: Riverside Inland Valleys Management Area
----------------------------------------------------------------------------------------------------------------
March Air Reserve Base..........  [3a; 44 ac (18      0 ac (0 ha).......  3a; no longer       0 ac (0 ha).
                                   ha)];.                                  meets definition
                                  Removed...........                       of essential;
                                                                           PCEs no longer
                                                                           present.

[[Page 31703]]

 
March Air Reserve Base..........  3b; Excluded under  101 ac (41 ha)....  3b; no longer       0 ac (0 ha).
                                   section 4(b)(2).                        meets definition
                                                                           of essential;
                                                                           PCEs no longer
                                                                           present.
Australia Pool..................  Excluded under      529 ac (214 ha)...  3c................  19 ac (8 ha).
                                   section 4(b)(2).
Scott Road Pools................  Excluded under      15 ac (6 ha)......  3d................  9 ac (4 ha).
                                   section 4(b)(2).
Schleuniger Pool................  Excluded under      136 ac (55 ha)....  3e................  23 ac (9 ha).
                                   section 4(b)(2).
Skunk Hollow and Field Pool       Excluded under      230 ac (93 ha)....  3f................  163 ac (66 ha).
 (Barry Jones Wetland Mitigation   section 4(b)(2).
 Bank).
Johnson Ranch Created Pools.....  Excluded under      82 ac (33 ha).....  3g................  54 ac (22 ha).
                                   section 4(b)(2).
Santa Rosa Plateau--Mesa de       Excluded under      4,394 ac (1,778     3h................  597ac
 Colorado.                         section 4(b)(2).    ha).                                   (242 ha).
----------------------------------------------------------------------------------------------------------------
                        Unit 4: San Diego North and Central Coastal Mesas Management Area
----------------------------------------------------------------------------------------------------------------
MCB Camp Pendleton..............  4(a)(3) exemption.  2,936 ac (1,188     4(a)(3) exemption.  1,929 ac (780 ha).
                                                       ha).
Poinsettia Lane Commuter Station  2c; partially       22 ac (9 ha)......  4c................  9 ac (4 ha).
                                   excluded under
                                   section 4(b)(2).
Miramar (AA1 East)..............  4(a)(3) exemption.  117 ac (47 ha)....  4(a)(3) exemption.  59 ac (24 ha).
----------------------------------------------------------------------------------------------------------------
                            Unit 5: San Diego: Southern Coastal Mesas Management Area
----------------------------------------------------------------------------------------------------------------
Sweetwater (J33)................  Proposed 5a;        3 ac (1 ha).......  5a................  2 ac (1 ha).
                                   partially
                                   excluded under
                                   section 4(b)(2).
Arnie's Point (J15).............  Proposed 5a.......  122 ac (49 ha)....  5b................  29 ac (12 ha).
Otay Mesa (including J2, J4, J5,  Excluded under      2,004 ac (811 ha)   Now includes 5a,    ..................
 J11, J14, J15, J16-18, J33).      section 4(b)(2).    \1\.                5b, 5e, 5f, 5g,
                                                                           5h.
East Otay Mesa (undescribed)....  5c; partially       111 ac (45 ha)....  5c................  57 ac (23 ha).
                                   excluded under
                                   section 4(b)(2).
J23-J25, formerly part of east    Excluded under      301 ac (122 ha)...  Not proposed,       0 ac (0 ha).
 Otay Mesa.                        section 4(b)(2).                        determined not
                                                                           essential.
J19, J21, J27-28................  Excluded under      524 ac (212 ha)...  Not proposed,       0 ac (0 ha).
                                   section 4(b)(2).                        determined not
                                                                           essential.
J29-J31, J2 N, J4, J5 (includes   Excluded under      645 ac (261 ha)...  5d................  370 ac (150 ha).
 Robinhood Ridge).                 section 4(b)(2).
                                  Excluded under      portion of 2,004    5e................  44 ac (18 ha).
                                   section 4(b)(2).    ac (811 ha) \1\.
J2 S, J2 W (includes Hidden       Excluded under      portion of 2,004    5f................  33 ac (13 ha).
 Valley, Cal Terraces, and Otay    section 4(b)(2).    ac (811 ha) \1\.
 Mesa Road).
J14.............................  Excluded under      ortion of 2,004 ac  5g................  136 ac (55 ha).
                                   section 4(b)(2).    (811 ha) \1\.
J11E, J11 W, J12, J16-19........  Excluded under      portion of 2,004    5h................  255 ac (103 ha).
                                   section 4(b)(2).    ac (811 ha) \1\.
----------------------------------------------------------------------------------------------------------------
    Total Area Essential for the  ..................  13,535 ac (5,477    5 units, 25         4,974 ac (2,013
     Conservation of Riverside                         ha).                subunits.           ha).
     fairy shrimp**.
----------------------------------------------------------------------------------------------------------------
**Note: Column may not add due to rounding.
*Location is based on vernal complex names used in 1998 Recovery Plan; unit names are based on Management Areas
  as identified in the 1998 Recovery Plan.
**Values in this table may not sum due to rounding.
\1\ 2,004 ac (811 ha) formerly ``lumped sum'' under Otay Mesa vernal pool complexes--these are now identified as
  individual subunits: 5a, 5b, 5e, 5f, 5g, 5h.


[[Page 31704]]

    The following section provides detailed descriptions of the changes 
made in this proposed rule and points to new information that 
precipitated each change.
    The PCEs in this proposed rule describe the ephemeral wetland 
habitat where Riverside fairy shrimp occur along with associated 
hydrological attributes (ponding, water chemistry, dry down) (PCE 1), 
the upland habitat (watershed and underlying hydrology) characteristics 
that support the ephemeral wetlands and their function (PCE 2), and the 
soils and topography (PCE 3) that allow water to pond during winter and 
spring months. Compared to the 2005 PCE regarding the vernal pools 
where Riverside fairy shrimp occur (ephemeral wetland habitats), we 
have added information about the necessary timing and duration of 
ponding and broadened the range of physiochemical parameters that may 
occur in order to more clearly characterize the breadth of conditions 
in which this species occurs (PCE 1). For the 2005 PCE involving the 
local watershed and filling of the ephemeral wetland habitat 
(intermixed wetland and upland habitats that act as a local watershed), 
we now discuss the land features (topography) that contribute to a 
functional hydrologic regime (i.e., local watershed) (PCE 2). For the 
2005 PCE that related to soil types associated with habitat for 
Riverside fairy shrimp (soils that support ponding during winter and 
spring), we now state that hardpan or claypan soil series types 
(including a partial list) create an impermeable surface or subsurface 
and facilitate the slow percolation and minimal run-off of water 
necessary for the ephemeral wetland habitat where Riverside fairy 
shrimp occur (PCE 3).
    Similar to the 2005 critical habitat, we used the 1998 Recovery 
Plan as a guide; however, in this proposed revised critical habitat we 
conducted additional analyses of all the Riverside fairy shrimp data 
currently available which are substantially more complete than what was 
known at the time the 1998 Recovery Plan was approved. The result of 
our additional analysis is that some areas identified as essential in 
the 2005 designation were removed, and other areas that were not 
identified as essential in the 2005 rule, such as areas in existence at 
the time of listing but not evaluated or included due to lack of 
surveys for Riverside fairy shrimp, are included in this proposed rule.
    In this proposed revised critical habitat designation, we have 
described the steps used to identify and delineate the areas we are 
proposing as revised critical habitat in better detail compared to the 
2005 critical habitat designation, to ensure that the public better 
understands why the areas are being proposed as critical habitat. In 
improving our explanation and intent, we have discontinued the use of 
the ``core'' and ``satellite'' population areas, as further discussed 
below.
    In the 2004 proposed critical habitat designation (69 FR 23024; 
April 27, 2004), we discussed the areas that represent ``core 
population areas'' and ``isolated population areas'' for Riverside 
fairy shrimp. Core population areas are defined in the 2004 proposed 
rule (69 FR 23027; April 27, 2004) as multiple pools or pool complexes 
containing Riverside fairy shrimp that are within close proximity 
(approximately 5 mi (8 km)) of other occupied pools and pool complexes 
and that contain the necessary PCEs to support one or more life-history 
functions essential to the conservation of Riverside fairy shrimp. 
Isolated populations are defined in the 2004 proposed rule (69 FR 
23027; April 27, 2004) as single pools or pool complexes that are known 
to contain Riverside fairy shrimp, are separated from other known 
locations by greater than 10 mi (16 km), and which contain the 
necessary PCEs to support one or more life-history functions essential 
to the conservation of Riverside fairy shrimp.
    Four ``core'' population areas--Orange County Foothills, Western 
Riverside County, the southern coastal portion of Camp Pendleton in San 
Diego County, and Otay Mesa in San Diego County--and seven isolated 
(``satellite'') populations--the City of Moorpark in Ventura County; 
Cruzan Mesa and Los Angeles International Airport in Los Angeles 
County; March Air Reserve Base and near the City of Banning in 
Riverside County; and in the City of Carlsbad and on MCAS Miramar in 
San Diego County--were identified as essential for Riverside fairy 
shrimp in the 2004 proposed critical habitat designation (69 FR 23024; 
April 27, 2004). We have discontinued the use of this ``core'' and 
``satellite'' terminology for labeling areas essential to the 
conservation of the species and have focused on the habitat 
characteristics of essential areas.
    Large, interconnected ephemeral wetland areas supporting vernal 
pools or vernal pool complexes in areas with potential for more species 
complexity and associations are essential to, and will serve as anchors 
for, the overall conservation of this species. As discussed in the 1998 
Recovery Plan, conserving larger, interconnected wetland areas with 
representative habitat heterogeneity (consisting of dissimilar elements 
or parts) adjacent to lands with compatible uses are generally 
preferable to smaller, more isolated pools (Service 1998a, p. 61). 
Conservation of these areas will sustain the largest populations of 
Riverside fairy shrimp, allowing the species to persist where it will 
be less constrained by the threats that negatively impact its essential 
habitat features (PCEs). However, more isolated (i.e., separated from 
other known locations by greater than 10 mi (16 km)) habitat areas also 
support stable, intact occurrences of Riverside fairy shrimp and are 
also essential to the conservation of the species. Preservation of 
remaining habitat, including the more isolated pools, serves a 
fundamental role in the survival and recovery of Riverside fairy shrimp 
because these areas may represent unique habitat and assemblages within 
this species' range. A full array of vernal pools and their constituent 
species, including a range of physical attributes that characterize 
various occurrences and associations (e.g., pool soils and topography) 
may be as rare as the individual species associated with them. The more 
isolated habitat areas occur over a wide range of soils and at various 
elevations such that, over a range of environmental variables, the 
preservation of these pools will help maintain the genetic diversity 
and adaptive potential of Riverside fairy shrimp and may enable them to 
survive and potentially respond to future environmental changes and 
threats. In summary, we believe the areas proposed in this revised 
critical habitat would provide for the conservation of Riverside fairy 
shrimp by: (1) Maintaining the physical and biological features 
essential to the conservation of the species in areas where Riverside 
fairy shrimp are known to occur; (2) maintaining the current 
distribution of Riverside fairy shrimp, and thus preserving an array of 
unique habitat and assemblages within this species' range, preserving 
genetic variation and adaptive potential of Riverside fairy shrimp 
throughout its range, and minimizing the potential effects of local 
extinction; and (3) including an area that was not occupied at the time 
of listing but that is essential to conserve the species.
    In the 2005 final critical habitat designation, both larger, 
interconnected ephemeral wetland areas and isolated, small basins and 
pools were identified as essential to the conservation of the species 
due largely in part to the species' limited numbers and distribution 
(Service 2005, p. 19178). Given the historical loss of vernal pool

[[Page 31705]]

habitat in southern California (Mattoni and Longcore 1997; Bauder and 
McMillian 1998; Keeler-Wolf et al. 1998), the conservation of the few 
remaining occurrences of Riverside fairy shrimp was considered 
essential for its conservation (Service 1998a). Further, given that 
Riverside fairy shrimp have a narrow geographic distribution and unique 
and specialized habitat requirements within that range, we concluded in 
the 2004 proposed critical habitat designation that all known occupied 
locations of Riverside fairy shrimp were essential to the conservation 
of the species (Service 2004, p. 23027). In this proposed revised 
designation, we have concluded that the conservation of the remaining 
occupied locations of Riverside fairy shrimp within the geographical 
range known at the time of listing, and the one created pool area 
outside the known geographical location at the time of listing capture 
those areas essential to the conservation of the species. We used the 
following criteria in the selection of areas that contain the essential 
features for the Riverside fairy shrimp and focused on designating 
units and subunits in: (1) Areas throughout the current geographic, 
elevation, and ecological distribution of the species; (2) areas that 
maintain the current population structure across the species' range; 
(3) areas that retain or provide for connectivity within occupied sites 
such that they would allow for water or wind dispersal to adjacent 
ephemeral wetland habitat; (4) areas that possess large continuous 
blocks of occupied habitat, representing source populations and/or 
unique ecological characteristics; and (5) areas that contain 
sufficient upland habitat around each occupied location to allow for 
sufficient survival and recruitment to maintain a self-sustaining 
population over the long term.
    By improving our mapping methodology, we more accurately define the 
critical habitat boundaries and better represent those areas that 
possess the physical and biological features essential to the 
conservation of Riverside fairy shrimp. In the 2005 final rule, we used 
a 100-meter grid resolution to delineate critical habitat, which 
resulted in more poorly defined and larger critical habitat areas. In 
this proposed rule, we accurately mapped areas that contain the PCEs by 
directly approximating the delineation of essential features rather 
than using a 100-meter grid. We believe the result is a more precise 
mapping of the habitat features and the areas which contain features 
essential to the conservation of the species. In this proposed revised 
critical habitat, upland areas (located immediately surrounding the 
vernal pool basins) and ephemeral wetlands (areas that contain one or 
more of the PCEs for the Riverside fairy shrimp) were mapped based on 
topographic features such as ridges, mounded micro-topography (mima 
mounds), and elevation gradients or slopes. Boundaries for these areas 
were further refined and delineated by mapping those areas that slope 
toward the pools, from highest point to highest point in the immediate 
surrounding upland areas, following the map's topographic elevation 
gradient around the high points (peaks), to the sides and the lowest 
part of the basin that encompass the complex of vernal pools. Those 
areas that the topographic maps show sloping steeply away from the 
pools, or that are developed or altered, such that necessary PCEs (for 
example, water, soil, and minerals) cannot be transported toward the 
vernal pools over such areas, are left outside of the refined 
delineation. This method was used for vernal pools in both basin and 
mesa-type topographic settings. Although our mapping methodology 
results in fewer described acres captured, it is a more accurate 
depiction of critical habitat boundaries that possess the physical and 
biological features essential to the conservation of the species.
    The 2005 final critical habitat designation (70 FR 19154; April 12, 
2005) included 4 units, one of which consisted of two subunits (1A and 
1B), comprising a total of 306 ac (124 ha). We identified an additional 
13,607 ac (5,506 ha) of land containing features essential to the 
conservation of Riverside fairy shrimp that were exempted from the 2005 
critical habitat designation pursuant to section 4(a)(3)(B)(i) of the 
Act, or excluded under section 4(b)(2) of the Act (70 FR 19180; April 
12, 2005). This proposed rule identifies 4,972 ac (2,012 ha) considered 
to contain the physical and biological features essential to the 
conservation of Riverside fairy shrimp (including military land exempt 
under section 4(a)(3) of the Act (see Table 1, above, and Table 3, 
below)). The essential habitat identified in this proposed revision is 
9,504 ac (3,846 ha) less than we identified as essential, inclusive of 
what was excluded or exempted, in the 2005 rule. The acreage reduction 
is primarily due to our attempt to more accurately delineate the areas 
that contain the physical and biological features essential to the 
conservation of Riverside fairy shrimp. We acknowledge the possibility 
that, due to mapping, data, and resource constraints, there may be some 
undeveloped areas mapped as critical habitat that do not contain the 
PCEs. We made every effort to exclude all developed areas, and other 
land unlikely to contain primary constituent elements essential for 
Riverside fairy shrimp conservation. Any such structures remaining 
inside the proposed revised critical habitat are not considered part of 
the units. This also applies to the land on which the structure lies. A 
brief discussion of each area designated as critical habitat is 
provided in the unit descriptions below.
    We identified several areas that are exempt under section 
4(a)(3)(B)(i) of the Act or will be considered for exclusion under 
section 4(b)(2) of the Act (see Table 3). In this proposed rule, eight 
areas (seven areas on MCB Camp Pendleton (1,929 ac (781 ha)) and one 
area on MCAS Miramar (59 ac (24 ha)) are determined exempt under 
section 4(a)(3)(B)(i) of the Act. These lands are on land owned, 
managed, or under the control of the Department of Defense and are 
addressed in an approved integrated natural resources management plan 
(INRMP) (in the case of San Onofre State Beach, State Park-leased lands 
under the Real Estate Agreements and Leases section of the INRMP; see 
Exclusions section below). Military lands exempt from proposed 
designation under section 4(a)(3)(B) of the Act are not assigned 
subunit identifiers; however, MCB Camp Pendleton falls within Unit 4 as 
discussed in the unit descriptions below. We will consider certain 
areas for exclusion from final designation under section 4(b)(2) of the 
Act. Any exclusion in the final revised critical habitat designation 
could differ from the exclusions we made in the 2005 final critical 
habitat designation.

[[Page 31706]]



 Table 3--(1) Proposed Habitat Determined To Be Essential, (2) Proposed
   Habitat Exempted Pursuant to 4(a)(3)(B)(i) of the Act, (3) Proposed
  Habitat Being Considered for Exclusion Pursuant to Section 4(b)(2) of
 the Act Under HCP, (4) Proposed Habitat Being Considered for Exclusion
  Pursuant to Section 4(b)(2) for National Security Reasons, (5) Total
  Proposed Habitat Considered for Exclusion, (6) Total Proposed Habitat
 Considered for Exemption and Exclusion, and (7) Total Habitat Proposed
              as Revised Critical Habitat in This 2011 Rule
------------------------------------------------------------------------
 
------------------------------------------------------------------------
(1) Habitat determined to be          4,972 ac (2,012 ha).
 essential to the conservation of
 the Riverside fairy shrimp.
(2) Proposed habitat exempted         1,988 ac (805 ha).
 pursuant to section 4(a)(3)(B)(i)
 of the Act (MCAS Miramar and MCB
 Camp Pendleton).
(3) Proposed habitat being            1,219 ac (493 ha).
 considered for exclusion pursuant
 to section 4(b)(2) of the Act under
 approved habitat conservation plan
 (HCP).
(4) Proposed habitat being            0 ac (0 ha).
 considered for exclusion pursuant
 to section 4(b)(2) for national
 security reasons.
(5) Total proposed habitat            1,219 ac (493 ha).
 considered for exclusion.
(6) Total proposed habitat exempted   3,207 ac (1,298 ha).
 or considered for exclusion.
(7) Total habitat proposed in 2011    2,984 ac (1,208 ha).
 as revised critical habitat (total
 proposed minus total exempted).
------------------------------------------------------------------------

    We have identified several areas that are being considered for 
exclusion under section 4(b)(2) of the Act (see Table 3). In the 2005 
rule, we excluded several subunits under section 4(b)(2) of the Act 
within the planning boundaries of: (a) The Orange County Southern 
Subregion HCP, (b) the draft City of Oceanside Subarea Plan and the 
City of Carlsbad's HMP under the MHCP, (c) the Western Riverside County 
MSHCP, and (d) the City and County of San Diego Subarea Plans under the 
MSCP. In this proposed revised critical habitat rule, we identified 
several areas we are considering for exclusion under section 4(b)(2) of 
the Act within the planning boundaries of, as follows: (a) The Orange 
County Central-Coastal subregional NCCP/HCP, (b) The Orange County 
Southern Subregion HCP, (c) the City of Carlsbad's HMP under the MHCP, 
(d) the Western Riverside County MSHCP, and (e) the County of San Diego 
Subarea Plan under the MSCP (see the Exclusions section).
    We are requesting public comment on the potential exclusion of 89 
ac (36 ha) covered by the Orange County Central-Coastal subregional 
NCCP/HCP; 233 ac (94 ha) covered by the Orange County Southern 
Subregion HCP; 865 ac (350 ha) covered by the Western Riverside County 
MSHCP; 9 ac (4 ha) covered by the Carlsbad HMP under the MHCP; and 23 
ac (9 ha) covered by the County of San Diego Subarea Plan under the 
MSCP. Any exclusions we make in the final revised critical habitat 
designation may differ from the exclusions we made in the 2005 final 
critical habitat designation.
    Areas designated as critical habitat units in this proposed rule 
are divided into five separate units (Units 1 through 5) which follow 
the six Management Areas presented in the 1998 Recovery Plan (Service 
1998a, p. 38). We have combined two management areas identified in the 
1998 Recovery Plan, the San Diego: North Coastal Mesas Management Area 
and the San Diego: Central Coastal Mesas Management Area into one, 
single unit (Unit 4) for this proposed rule. The management areas are 
based primarily on geographical locations, although we have considered 
these locations in terms of underlying soil types and geomorphic 
processes, size and type of associated watershed, and topographic 
position (i.e., coastal mesa, inland valley, on granitic soils, etc.). 
Where possible, unit and subunit labels in this proposed rule follow 
previous naming conventions found in the 2005 critical habitat. We have 
retained original names associated with management areas, units, 
subunits, or pool complex names, where possible, to reduce confusion 
and promote consistency between previous rules and this proposed 
revision. Changes from the 2005 final critical habitat rule, however, 
include the following unit name reassignments: Unit 3 now includes land 
in Riverside County (land previously excluded from the 2005 designation 
of critical habitat and which, therefore, had no unit or subunit 
numbers assigned), and Unit 5 now incorporates Otay Mesa in southern 
San Diego County, previously labeled as Unit 4 in the 2005 rule. As 
with the 2005 final critical habitat rule, some land within the San 
Diego North and Central Coastal Mesa Management Areas (Service 1998a, 
p. 46) has not been proposed because these lands have been determined 
to be exempt under 4(a)(3)(B)(i) of the Act (MCAS Miramar and MCB Camp 
Pendleton) (see Tables 1 and 2 above; and Exemptions section below).
    Following a new analysis of the best available scientific 
information, proposed habitat areas have been added or subtracted based 
on new information received. In Table 2 above, we have provided a 
comparison between the 2005 final critical habitat designation and this 
proposed revised critical habitat rule and identify the change in area 
(by subunit) between the 2005 critical habitat designation and this 
proposed revised critical habitat designation. As already stated, some 
areas designated in the 2005 rule are not being proposed for 
designation because they do not meet the criteria used to identify 
areas essential to the conservation of Riverside fairy shrimp (see 
Criteria Used to Identify Critical Habitat for additional discussion). 
Further we are proposing to designate as revised critical habitat areas 
not considered in the 2005 final designation (Johnson Ranch Created 
Pools).
    Two areas identified as meeting the definition of critical habitat 
in the 2004 proposed rule, but removed from the 2005 final critical 
habitat designation, are not proposed in this revision of critical 
habitat (Los Angeles Airport and March Air Reserve Base). The best 
available scientific and commercial data indicate these two areas no 
longer contain the physical and biological features essential to the 
conservation of the species and that the species has been extirpated. 
Further, we are not proposing three areas (Cruzan Mesa in Los Angeles, 
Banning in western Riverside County, and Wire Mountain in San Diego 
County) in this proposed rule, because we believe that these areas do 
not meet the definition of critical habitat, and because we do not 
possess sufficient data to substantiate Riverside fairy shrimp 
occurrence (we have conflicting accounts of positive species 
identification). San Mateo Pool (MCB Camp Pendleton, San Diego County) 
has been removed from our proposed designation because we possess 
insufficient data to evaluate its current status or condition, need for 
special management, or persistence of the occurrence and we, therefore, 
do not consider it to meet the definition of critical habitat. In the 
2005 final critical habitat designation for Riverside fairy shrimp, we 
mentioned evidence of two vernal pools on or near tribal land

[[Page 31707]]

within the Pechanga Band of Luise[ntilde]o Mission Indians reservation 
(6 ac (2 ha)) near the City of Temecula with possible historical 
occurrences, but, based on information available from 2004, we were 
unable to confirm these occurrences (70 FR 19199). Due to insufficient 
occurrence information and evidence of severely modified and impacted 
pools from years of discing and plowing, we are not proposing to 
designate critical habitat on tribal lands of the Pechanga Band of 
Luise[ntilde]o Mission Indians (see Public Comments section above).
    For three areas in this rule (portions of proposed Subunits 5b, 5c, 
and 5h), we have removed portions of the areas previously defined as 
essential in 2005 because, due to their proximity to the border and 
ongoing impacts from border patrol activities, we believe they no 
longer contribute to the long-term viability of Riverside fairy shrimp. 
More information about the units and subunits that contain the physical 
and biological features essential to the conservation of Riverside 
fairy shrimp and an explanation of how the added or removed areas do or 
do not contribute to the conservation of Riverside fairy shrimp is 
provided below in the Proposed Revised Critical Habitat Designation 
section.
    In summary, on April 27, 2004, we proposed revised critical habitat 
of 5,795 ac (2,345 ha) in 5 units, including 19 subunits, located in 
Los Angeles, Orange, Riverside, San Diego and Ventura Counties. In 
response to information received during the public comment periods for 
our 2004 proposed critical habitat, refined mapping methodology, and 
re-evaluation of essential habitat, we removed 4,822 ac (1,951 ha) of 
non-essential habitat from the designation (Cruzan Mesa and Los Angeles 
Airport (Los Angeles County), March Air Reserve Base (Riverside 
County), and portions within southwestern and southeastern Otay Mesa 
(San Diego County)). In 2005, we designated approximately 306 ac (124 
ha) as critical habitat for Riverside fairy shrimp in 4 units, one of 
which consisted of two subunits (1A and 1B) (70 FR 19154; April 12, 
2005). For this proposed revision, we have included 5 units, including 
25 subunits, comprising a total of 2,984 ac (1,208 ha) of land 
determined to be essential to the conservation of Riverside fairy 
shrimp.

Proposed Revised Critical Habitat Designation

    We propose to designate 2,984 ac (1,208 ha) in 5 units, containing 
25 subunits, as critical habitat for Riverside fairy shrimp. The 
critical habitat areas we describe below constitute our current best 
assessment of areas that meet the definition of critical habitat for 
Riverside fairy shrimp. The proposed revised critical habitat includes 
Riverside fairy shrimp habitat throughout the species' range in the 
United States. Proposed units generally correspond to the geographic 
areas identified as ``Management Areas'' in the 1998 Recovery Plan 
(Service 1998a, pp. 35-44). This proposed rule, when finalized, will 
supersede the 2005 critical habitat designation for Riverside fairy 
shrimp in 50 CFR 17.95(h).
    The five map units proposed for designation as critical habitat are 
referred to by the following geographical names: (Map Unit 1) Ventura 
County (Transverse Range); (Map Unit 2) Los Angeles Basin--Orange 
County Foothills; (Map Unit 3) Riverside County Inland Valleys; (Map 
Unit 4) San Diego Northern and Central Coastal Mesas; and (Map Unit 5) 
San Diego Southern Coastal Mesas. Areas proposed as revised critical 
habitat are under Federal, State, local, and private ownership. The 
approximate area of proposed revised critical habitat by county and 
land ownership is shown in Table 4.

                                          Table 4--Proposed Revised Critical Habitat for Riverside Fairy Shrimp
                                                              [Not including exempted land]
--------------------------------------------------------------------------------------------------------------------------------------------------------
       Critical habitat unit              Federal land             State land              Local land            Private land            Total area
--------------------------------------------------------------------------------------------------------------------------------------------------------
Unit 1: Ventura County.............  ......................  ......................  31 ac (13 ha)........  435 ac (176 ha)......  466 ac (189 ha).
1a. Tierra Rejada Preserve.........  ......................  ......................  .....................  18 ac (7 ha).........  18 ac (7 ac).
1b. South of Tierra Rejada.........  ......................  ......................  31 ac (13 ha)........  417 ac (169 ha)......  448 ac (182 ha).
Valley.............................
Unit 2: Los Angeles Basin--Orange    ......................  ......................  142 ac (58 ha).......  576 ac (233 ha)......  718 ac (291 ha).
 County Foothills.
2c. (MCAS) El Toro.................  ......................  ......................  18 ac (7 ha).........  8 ac (3 ha)..........  26 ac (11 ac).
2dA. Saddleback Meadows............  ......................  ......................  4 ac (2 ha)..........  252 ac (102 ha)......  256 ac (104 ha).
2dB. O'Neill Regional Park--near     ......................  ......................  75 ac (30 ha)........  15 ac (6 ha).........  90 ac (37 ha).
 Trabuco Canyon.
2e. O'Neill Regional Park--near      ......................  ......................  45 ac (18)...........  24 ac (10 ha)........  69 ac (28 ha).
 Ca[ntilde]ada Gobernadora.
2f. Chiquita Ridge.................  ......................  ......................  .....................  56 ac (23 ha)........  56 ac (23 ha).
2g. Radio Tower Road...............  ......................  ......................  .....................  51 ac (21 ha)........  51 ac (21 ha).
2h. San Onofre State Beach, State    ......................  ......................  .....................  107 ac (43 ha).......  107 ac (43 ha).
 Park-leased land (near
 Christianitos Creek foothills).
2i. SCE Viejo Conservation Bank....  ......................  ......................  .....................  63 ac (25 ha)........  63 ac (25 ha).
Unit 3: Riverside Inland Valleys...  ......................  54 ac (22 ha).........  .....................  811 ac (328 ha)......  865 ac (350 ha).
3c. Australia Pool.................  ......................  ......................  .....................  19 ac (8 ha).........  19 ac (8 ha).
3d. Scott Road Pool................  ......................  ......................  .....................  9 ac (4 ha)..........  9 ac (4 ha).
3e. Schleuniger Pool...............  ......................  ......................  .....................  23 ac (9 ha).........  23 ac (9 ha).

[[Page 31708]]

 
3f. Skunk Hollow and Field Pool      ......................  ......................  .....................  163 ac (66 ha).......  163 ac (66 ha).
 (Barry Jones Wetland Mitigation
 Bank).
3g. Johnson Ranch Created Pools....  ......................  54 ac (22 ha).........  .....................  .....................  54 ac (22 ha).
3h. Santa Rosa Plateau--Mesa de      ......................  ......................  .....................  597 ac (242 ha)......  597 ac (242 ha).
 Colorado.
Unit 4: San Diego North and Central  ......................  6 ac (3 ha)...........  .....................  3 ac (1 ha)..........  9 ac (4 ha).
 Coastal Mesas.
4c. Poinsettia Lane Train Station..  ......................  6 ac (3 ha)...........  .....................  3 ac (1 ha)..........  9 ac (4 ha).
Unit 5: San Diego Southern Coastal   40 ac (16 ha).........  256 ac (104 ha).......  157 ac (64 ha).......  472 ac (191 ha)......  925 ac (375 ha).
 Mesas.
5a. Sweetwater (J33)...............  ......................  ......................  2 ac (less than 1 ha)  less than 1 ac (0 ha)  2 ac (less than 1
                                                                                                                                    ha).
5b. Arnie's Point (J15)............  29 ac (12 ha).........  ......................  .....................  .....................  29 ac (12 ha).
5c. East Otay Mesa.................  ......................  ......................  .....................  57 ac (23 ha)........  57 ac (23 ha).
5d. J29-31.........................  less than 1 ac (0 ha).  211 ac (85 ha)........  .....................  159 ac (64 ha).......  370 ac (149 ha).
5e. J2 N, J4, J5: (Robinhood Ridge)  ......................  ......................  32 ac (13 ha)........  12 ac (5 ha).........  44 ac (18 ha).
5f. J2 W and J2 S: (Hidden Trails,   ......................  ......................  22 ac (9 ha).........  11 ac (4 ha).........  33 ac (13 ha).
 Cal Terraces, Otay Mesa Road).
5g. J14............................  ......................  45 ac (18 ha).........  18 ac (7 ha).........  72 ac (29 ha)........  135 ac (55 ha).
5h. J11 E and J11 W, J12, J16-18     11 ac (4 ha)..........  ......................  83 ac (34 ha)........  161 ac (65 ha).......  255 ac (103 ha).
 (Goat Mesa).
                                    --------------------------------------------------------------------------------------------------------------------
    Totals.........................  40 ac (16 ha).........  316 ac (128 ha).......  330 ac (135 ha)......  2,297 ac (929 ha)....  2,984 ac (1,208 ha).
--------------------------------------------------------------------------------------------------------------------------------------------------------
Note: Sums of land areas may not total due to rounding.

    We present brief descriptions of all units, and reasons why they 
meet the definition of critical habitat for Riverside fairy shrimp, 
below.
Unit 1: Ventura County Unit (Transverse Range)
    Unit 1 is located in central Ventura County and consists of two 
occupied subunits totaling approximately 31 ac (13 ha) of local land 
and 435 ac (176 ha) of private land. This proposed unit includes the 
vernal pools near the city of Moorpark in Ventura County, at Tierra 
Rejada Preserve (formerly called Carlsberg Ranch) on the west side of 
State Highway 23, and a basin to the southeast of Carlsberg Ranch site, 
east of State Highway 23 called South of Tierra Rejada Valley. This 
unit occurs within the larger Santa Clara-Calleguas/Calleguas-Conejo 
Tierra Rejada Valley watershed, within the east-west trending 
Transverse (mountain) Range. The Transverse Range system was formed by 
the interaction of an east-west oceanic fault zone with the San Andreas 
Fault. Because the interaction of the two fault systems has been 
extensive and continues with rapid local uplift, Riverside fairy shrimp 
habitat within the Transverse Range reflects past activities of 
tectonic processes and their effects on watershed development. 
Accelerated erosion, sedimentation, and debris processes, such as mud 
and rock flows, landslides, wind flows, and debris flows (i.e., soil-
development processes), contribute to a unique set of physiochemical 
and geomorphic features for pools occupied by Riverside fairy shrimp.
Subunit 1a: Tierra Rejada Preserve
    Subunit 1a is located near the City of Moorpark, in southeastern 
Ventura County, California. This subunit is located on what was 
formerly known as the Carlsberg Ranch, at the north end of the Tierra 
Rejada Valley, just west of State Highway 23. It is near the northeast 
intersection of Moorpark Road and Tierra Rejada Road in a residential 
housing development. Subunit 1a consists of 18 ac (7 ha) of privately 
owned land. The vernal pool (pond), 4.6 acres (1.7 ha) in size, is 
located in the Tierra Rejada Vernal Pool Preserve, owned and managed by 
Mountains Recreation and Conservation Authority (MCRA). Subunit 1a 
contains areas identified in the 1998 Recovery Plan (Appendix F) as 
necessary to stabilize and protect (conserve) existing populations of 
Riverside fairy shrimp.
    This subunit is occupied at the time of listing and remains 
occupied. Resting cysts were detected in recent soil analyses (Chris 
Dellith 2010, pers. comm.) and adult fairy shrimp were observed on 
April 7, 2011 (Judi Tamasi 2010, pers. comm.), the first observation of 
adults since the 2000-2001 ponding season. This area is essential to 
the conservation of this species for several reasons. The pool supports 
endangered Orcutt's grass (Orcuttia californica), which is an indicator 
of longer ponding duration. This pool is fundamentally different in 
terms of size, origin, depth and duration of ponding, contributing 
areas (watershed), and the thickness of the underlying sediments 
compared to flat areas of older soils with highly developed claypans 
and hardpans throughout the State (Hecht et al. 1998, p. 47); it was 
formed primarily by tilting and subsidence along the Santa Rosa fault 
(Hecht et al. 1998, p. 5). Given its geologic and hydrologic features 
and the associated wetland vegetation occurring within the subunit, 
this pool possesses a set of physical and biological factors unique to 
this occurrence to which the Riverside fairy shrimp has likely become 
adapted. The present biological resources and value of the pool have 
been sustained through ``substantial disturbance and change in general 
area of the vernal pool'' given history of land and water use and 
analysis of 60 years of aerial photography (Hecht et al. 1998, p. 6 and 
Appendix A). Although Lahti

[[Page 31709]]

et al. (2011) did not survey this pool during their completion of a 
rangewide genetic analysis, this occurrence does represent the 
northernmost extension of the species' occupied range, within a notably 
unique vernal wetland type (Hecht et al. 1998, p. 5 and see discussion 
below).
    Subunit 1a contains the physical and biological features that are 
essential to the conservation of Riverside fairy shrimp, including 
appropriate soil series (Azule, Calleguas, and Linne soil series; PCE 
3) situated on a saturated fault between rocks of different 
permeability (``tectonogenic'' Hecht et al. 1998, p. 5), and it is 
``sediment-tolerant'' given that it possesses a watershed with 
reasonably steep slopes (10-50 percent slopes) with scrub vegetation 
yielding substantial amounts of sediment that provide nutrients, 
minerals, and hydrology (Hecht et al. 1998, p. 6). Additionally, 
because of adjacent urban development, altered hydrology, and potential 
for runoff, this vernal pool may require special management 
considerations or protection for the recovery of Riverside fairy 
shrimp. This subunit has one large ponding feature, and is essential to 
maintain habitat function, genetic diversity, and species viability 
(Service 1998a, p. 65) at the species' northernmost geographical 
distribution.
    Due to its unique geographic location and other features stated 
above, Subunit 1a is essential to the conservation of Riverside fairy 
shrimp. Although preliminary genetic studies are not definitive with 
regards to gene flow and genetic variability across the range of this 
species, populations at the edge of a species' distribution have been 
demonstrated to be important sources of genetic variation and may 
provide an important opportunity for colonization or re-colonization of 
unoccupied vernal pools and, thus, contribute to long-term conservation 
(and recovery) of the species (Gilpin and Soul[eacute] 1986, pp. 32-33; 
Lande 1999, p. 6). Research on genetic differentiation among fairy 
shrimp species across their known distributions have demonstrated that 
geographically distinct populations may or may not be genetically 
distinct, but that they have unique genetic characteristics allowing 
for environmental changes (Bohonak 2003, p. 3; Lahti et al. 2010, p. 
17). These characteristics may not be present in other parts of a 
species' range (Lesica and Allendorf 1995, p. 756). For these reasons, 
subunit 1a is uniquely situated and considered essential for recovery 
of the Riverside fairy shrimp.
    The physical and biological features essential to the conservation 
of the species in this subunit may require special management 
considerations or protection to address threats from nonnative plant 
species (nonnative grasses and Schinus molle (Peruvian pepper groves)) 
and alterations to the hydrologic cycle including type conversion of 
habitat; activities that remove or destroy the habitat assemblage of 
the pools, such as creation of fuel breaks, mowing, and grading; and 
human encroachment that occurs in the area. For example, inundation 
from artificial water sources can cause pools to stay inundated longer 
than normal or even convert vernal pools into perennial pools that are 
not suitable for Riverside fairy shrimp (Service 2008, p. 16). Please 
see Special Management Considerations or Protection section of this 
proposed rule for a discussion of the threats to Riverside fairy shrimp 
habitat and potential management considerations.
Subunit 1b: South of Tierra Rejada Valley
    Subunit 1b is located near the City of Moorpark in Ventura County, 
California. This proposed subunit is approximately 1.5 km (1 mi) 
southeast of Subunit 1a and east of State Highway 23. Subunit 1b 
consists of 31 ac (13 ha) of locally owned land and 417 ac (169 ha) of 
private land. We assume that Subunit 1b was not identified in the 1998 
Recovery Plan (Appendix F) because at that time we were unable to 
confirm occupancy. To the best of our knowledge, this subunit has never 
been protocol surveyed to confirm presence or absence of Riverside 
fairy shrimp (Chris Dellith 2010, pers. comm.). This subunit, however, 
was proposed and designated as essential habitat in the previous 2005 
proposed revised critical habitat rule because we considered it 
occupied (see discussion below) and because the necessary PCEs were 
present. Although we continue to presume Subunit 1b is occupied despite 
the absence of protocol survey results and have determined that the 
subunit contains the PCEs and therefore meets the definition of 
critical habitat under Section 3(5)(A)(i) of the Act, we are also 
proposing to designate Subunit 1b under Section 3(5)(A)(ii) of the Act. 
Even if Subunit 1b was not occupied at the time of listing, the subunit 
is essential for the conservation of the species due to its suitable 
habitat conditions, proximity to subunit 1a, and location at the 
northernmost extent of the species' range.
    Subunit 1b is located approximately one mile to the south of Tierra 
Rejada Preserve (Subunit 1a), within the Tierra Rejada Valley 
watershed. Like Subunit 1a, this pool is one of the last 
representatives of what is believed to be a historic distribution of 
coastal terrace vernal pools common to the marine terraces and inland 
area of Ventura County prior to the 1950s. This subunit is considered 
occupied based on several factors which strongly suggest the likelihood 
of Riverside fairy shrimp occurrence. As discussed in the 2005 proposed 
rule (70 FR 19154, p. 19181) these are: (1) The important biotic and 
abiotic conditions (soil type, geology, morphology, local climate, 
topography, and plant associations, e.g. California Orcutt's grass) 
suggesting the presence of vernal pool ponding at appropriate season 
and for appropriate duration; (2) topographic features and ponding 
evidence based on aerial surveys confirming a ponding pool basin; (3) 
several large permanent and semi-permanent pools observed within the 
Subunit's local watershed; (4) proximity (less than 1 mi (1500 m)) to a 
known Riverside fairy shrimp occurrence and likely within the known 
dispersal distance expected for an invertebrate species with a 
resistant cyst stage; and (5) the determination that Subunit 1a and 
Subunit 1b are adjoined, based on fluvial and geomorphic evidence 
suggesting that the Tierra Rejada Valley river system once likely 
connected the two pools and would have provided the connectivity to 
disperse cysts between the two subunits.
    Subunit 1b is proposed as revised critical habitat because we have 
determined it to be essential for the conservation of the species as it 
includes one or more pools capable of maintaining habitat function, 
genetic diversity, and species viability (Service 1998a, p. 65) for 
Riverside fairy shrimp at the northern limit of its current 
distribution, and it is near, and likely has connectivity with, a known 
occupied location of ecological and distributional significance. It is 
also identified as essential because best supporting evidence indicates 
the basin contains appropriate depth and ponding duration (PCEs 1), 
soils and topography (PCEs 2 and 3), elevation, and water chemistry 
(pH, temperature, salinity, etc.; PCE 1) to satisfy life-history needs 
of existing populations, either on-site or located nearby within 
subunit 1a.
Unit 2: Los Angeles Basin--Orange County Foothills
    Unit 2 is located in central coastal Orange County and consists of 
8 subunits totaling approximately 718 ac (291 ha) of land. This unit 
contains 142 ac (58 ha) of locally owned land, and 576 ac (233 ha) of 
privately owned land. Unit 2 falls within the Los Angeles

[[Page 31710]]

Basin-Orange Management Area as outlined in the 1998 Recovery Plan. The 
majority of vernal pools in this management area were extirpated prior 
to 1950, and only a small number of vernal pools remain in Los Angeles 
and Orange Counties (Service 1998a, p. 40). This unit includes the 
vernal pools and vernal pool-like ephemeral ponds located along a 
north-south band in the Orange County Foothills. This unit includes 
examples of the historic distribution of coastal terraces at moderate 
elevations (183 m to 414 m (600 ft to 1,358 ft)) and includes ephemeral 
ponds formed by landslides and fault activity, and remnant stream 
(fluvial) terraces along foothill ridgelines (Taylor et al. 2006, pp. 
1-2).
    Occupied Riverside fairy shrimp pools occur on: former Marine Corps 
Air Station (MCAS) El Toro; SCE Viejo Conservation Bank; Saddleback 
Meadows; O'Neill Regional Park--near Trabuco Canyon (east of Tijeras 
Creek at the intersection of Antonio Parkway and the Foothill 
Transportation Corridor (FTC-north segment)); O'Neill Regional Park--
near Ca[ntilde]ada Gobernadora; Chiquita Ridge; Radio Tower Road; and 
San Onofre State Beach, State Park-leased land (near Christianitos 
Creek foothills) that falls partially within MCB Camp Pendleton. These 
vernal pools are the last remaining vernal pools in Orange County known 
to support this species (58 FR 41384) and represent pools of a unique 
type of vernal pool habitat that differs from the traditional mima 
mound vernal pool complexes of coastal San Diego County, the coastal 
pools at MCB Camp Pendleton, and the inland pools of Riverside County 
(70 FR 19182).
    The areas within Unit 2 were occupied at the time of listing, are 
still occupied, and contain the physical and biological features that 
are essential to the conservation of Riverside fairy shrimp, including 
ephemeral wetland habitat (PCE 1), intermixed wetland and upland 
habitats that act as the local watershed (PCE 2), and the topography 
and soils that support ponding during winter and spring months (PCE 3). 
In almost all cases, slow-moving or still surface water and/or 
saturated soils are present at or near vernal pool habitat. 
Conservation of an array of vernal pools supporting Riverside fairy 
shrimp in the foothill region of Orange County is essential to the 
conservation of the species by providing for necessary habitat 
function, natural genetic diversity and exchange, and species viability 
in the central portion of the species' range.
Subunit 2c: (MCAS) El Toro
    Subunit 2c is located in the City of Irvine, in southern Orange 
County, California. It is situated about 8 miles southeast of the city 
of Santa Ana and 12 miles northeast of the city of Laguna Beach. This 
subunit is approximately 0.75 km (0.5 mi) southeast of Portola Parkway 
and bounded to the northeast by California Highway 241. The Marine 
Corps Air Station (MCAS) El Toro was a jet air station supporting 
Pacific Fleet Marine Forces, and officially closed in 1999. Most of the 
MCAS El Toro site is in unincorporated territory over which the County 
of Orange has direct land use planning and development authority. 
Subunit 2c consists of 18 ac (7 ha) of locally owned land and 8 ac (3 
ha) of private land. Subunit 2c contains areas identified in the 1998 
Recovery Plan (Appendix F) as necessary to stabilize and protect 
(conserve) existing populations of Riverside fairy shrimp, as well as 
other proposed and listed vernal pool species.
    This subunit is considered essential for the recovery of Riverside 
fairy shrimp because it is currently occupied and includes one or more 
pools to maintain habitat function, genetic diversity, and species 
viability (Service 1998a, p. 65). Further, it is identified as 
essential because the basin contains appropriate depth and ponding 
duration, soils, elevation, and water chemistry (pH, temperature, 
salinity, etc.), which fulfill Riverside fairy shrimp's life-history 
needs. The habitat consists of a seasonal pond that appears to be 
artificial, and has been impacted, modified, and degraded by live 
munitions firings, groundwater contamination, and off-highway vehicle 
(OHV) use. Restoration of the pond began in 2001, and included the 
installation of monitoring wells for contamination and regular 
monitoring for Riverside fairy shrimp. Subunit 2c contains the physical 
and biological features that are essential to the conservation of 
Riverside fairy shrimp, including ephemeral wetland habitat (PCE 1), 
intermixed wetland and upland habitats that act as the local watershed 
(PCE 2), and the topography and soils that support ponding during 
winter and spring months (PCE 3).
    The physical and biological features essential to the conservation 
of the species in this subunit may require special management 
considerations or protection to address threats from nonnative plant 
species (nonnative grasses) that occur in the vernal pool basins, the 
potential for ongoing groundwater contamination, and OHV impacts. 
Please see the Special Management Considerations or Protection section 
of this proposed rule for a discussion of the threats to Riverside 
fairy shrimp habitat and potential management considerations. We are 
considering this subunit for exclusion under 4(b)(2) of the Act; please 
see the Exclusions section of this proposed rule for more information.
Subunit 2dA: Saddleback Meadows
    Subunit 2dA is located in the community of Silverado, in southern 
Orange County, California. This subunit is near the St. Michaels 
College Preparatory School, east of El Toro Road, and south and west of 
Live Oak Canyon Road. Subunit 2dA consists of 4 ac (2 ha) of locally 
owned land and 252 ac (102 ha) of privately owned land. Subunit 2dA 
contains areas identified in the 1998 Recovery Plan (Appendix F) as 
necessary to stabilize and protect (conserve) existing populations of 
Riverside fairy shrimp, as well as other proposed and listed vernal 
pool species.
    This subunit is considered essential for the recovery of Riverside 
fairy shrimp because it is currently occupied and includes one or more 
pools to maintain habitat function, genetic diversity, and species 
viability (Service 1998a, p. 65). Further, it is identified as 
essential because the basin contains appropriate depth and ponding 
duration, soils, elevation, and water chemistry (pH, temperature, 
salinity, etc.), which fulfill Riverside fairy shrimp's life-history 
needs. This vernal pool complex includes a series of natural and 
impounded cattle troughs that have been breached and degraded by past 
agricultural activities and urban development. In addition, Subunit 2dA 
is an important link to the northern occupied locations, and represents 
a nearby source for re-colonization of pools in the Orange County 
foothills. Proposed Subunit 2dA contains the physical and biological 
features that are essential to the conservation of Riverside fairy 
shrimp, including ephemeral wetland habitat (PCE 1), intermixed wetland 
and upland habitats that act as the local watershed (PCE 2), and the 
topography and soils that support ponding during winter and spring 
months (PCE 3).
    The physical and biological features essential to the conservation 
of the species in this subunit may require special management 
considerations or protection to address threats from nonnative plant 
species, development, or grazing that may occur in the vernal pool 
basins. Please see the Special Management Considerations or Protection 
section of this proposed rule for a discussion of the threats to

[[Page 31711]]

Riverside fairy shrimp habitat and potential management considerations. 
We are considering portions of this subunit for exclusion under 4(b)(2) 
of the Act; please see the Exclusions section of this proposed rule for 
more information.
Subunit 2dB: O'Neill Regional Park--Near Trabuco Canyon
    Subunit 2dB is located approximately 1.5 km (1 mi) southeast of 
Subunit 2dA in southern Orange County, California. This subunit is west 
of Live Oak Canyon Road, and northeast of the O'Neill Regional Park--
near Ca[ntilde]ada Gobernadora (see Subunit 2e below). In the 2008 5-
year review, this area was referred to as `O'Neill Park/Clay Flats pond 
property' (Service 2008, p. 7). Subunit 2dB consists of 75 ac (30 ha) 
of locally owned land (State Parks) and 15 ac (6 ha) of privately owned 
land. Subunit 2dB was not specifically identified in the 1998 Recovery 
Plan (Appendix F), but is classified as necessary to stabilize and 
protect (conserve) existing populations of Riverside fairy shrimp 
within the ``Orange County Foothills (undescribed)'' heading in 
Appendix F (Service 1998a, p. F1).
    This subunit is considered essential for the recovery of Riverside 
fairy shrimp because it is currently occupied and includes one or more 
pools essential to maintain habitat function, genetic diversity, and 
species viability (Service 1998a, p. 65). Further, it is identified as 
essential because the basin contains appropriate depth and ponding 
duration, soils, elevation, and water chemistry (pH, temperature, 
salinity, etc.), which fulfill Riverside fairy shrimp's life-history 
needs. This proposed subunit 2dB contains the physical and biological 
features essential to the conservation of Riverside fairy shrimp, 
including ephemeral wetland habitat (PCE 1), intermixed wetland and 
upland habitats that act as the local watershed (PCE 2), and the 
topography and soils that support ponding during winter and spring 
months (PCE 3). A portion of this subunit lies at 1,413 ft (431 m) and 
is among the highest elevation occurrences of Riverside fairy shrimp.
    The physical and biological features essential to the conservation 
of the species in this subunit may require special management 
considerations or protection to address threats from nonnative plant 
species and activities such as unauthorized recreational use, OHV use, 
and fire management. Please see the Special Management Considerations 
or Protection section of this proposed rule for a discussion of the 
threats to Riverside fairy shrimp habitat and potential management 
considerations. We are considering portions of this subunit for 
exclusion under 4(b)(2) of the Act; please see the Exclusions section 
of this proposed rule for more information.
Subunit 2e: O'Neill Regional Park--Near Ca[ntilde]ada Gobernadora/east 
of Tijeras Creek
    Subunit 2e is located near the City of Rancho Santa Margarita in 
southern Orange County, California. This subunit is east of 
Ca[ntilde]ada Gobernadora and bounded to the west by California Highway 
241. In the 2008 5-year review, this area was referred to as east of 
Tijeras Creek complex (Service 2008, p. 7). Subunit 2e consists of 45 
ac (18 ha) of locally owned land and 24 ac (10 ha) of private land. 
Subunit 2e was not specifically identified in the 1998 Recovery Plan 
(Appendix F), but was classified as necessary to stabilize and protect 
(conserve) existing populations of Riverside fairy shrimp within the 
``Orange County Foothills (undescribed)'' heading in Appendix F 
(Service 1998a, p. F1).
    This subunit is considered essential to the conservation of 
Riverside fairy shrimp because it is currently occupied and includes 
one or more pools essential to maintain habitat function, genetic 
diversity, and species viability (Service 1998a, p. 65). Further, it is 
identified as essential because the basin contains appropriate depth 
and ponding duration, soils, elevation, and water chemistry (pH, 
temperature, salinity, etc.), which fulfill Riverside fairy shrimp's 
life-history needs. Areas within this proposed subunit contain clay, 
clay loam, or sandy loam and consist primarily of dry-land agriculture 
and sagebrush-buckwheat scrub habitat. Located in the water drainages 
of the foothills of the Santa Ana Mountains, this pool rests in a 
canyon bottomland at approximately 919 ft (280 m) of elevation. Subunit 
2e contains the physical and biological features essential to the 
conservation of Riverside fairy shrimp because it: (1) Contains the 
PCEs for Riverside fairy shrimp, including clay soils and loamy soils 
underlain by a clay subsoil (PCE 3), areas with a natural, generally 
intact surface and subsurface soil structure (PCE 2), and the ephemeral 
habitat (PCE 1) that support Riverside fairy shrimp, including slow-
moving or still surface water and/or saturated soils; and (2) supports 
a stable, persistent occurrence of the species.
    The physical and biological features essential to the conservation 
of the species in this subunit may require special management 
considerations or protection to address threats from nonnative plant 
species and anthropogenic activities (e.g., surrounding residential and 
commercial development, unauthorized recreational use, OHV use, and 
fire management). Please see the Special Management Considerations or 
Protection section of this proposed rule for a discussion of the 
threats to Riverside fairy shrimp habitat and potential management 
considerations. We are considering portions of this subunit for 
exclusion under 4(b)(2) of the Act; please see the Exclusions section 
of this proposed rule for more information.
Subunit 2f: Chiquita Ridge
    Proposed Subunit 2f is located in the community of Trabuco, a small 
unincorporated community north of the town of Rancho Santa Margarita in 
Rancho Mission Viejo, in the southern Orange County foothills of 
California. This subunit is west of the Ca[ntilde]ada Chiquita Valley, 
east of Antonio Parkway, and approximately 3.5 km (2.25 mi) north of 
Ortega Highway State Route 74. This proposed subunit consists of 56 ac 
(23 ha) of privately owned land. Subunit 2f contains areas identified 
in the 1998 Recovery Plan (Appendix F) as necessary to stabilize and 
protect (conserve) existing populations of Riverside fairy shrimp, as 
well as other proposed and listed vernal pool species.
    This subunit is considered essential for the recovery of Riverside 
fairy shrimp because it is currently occupied and includes one or more 
pools essential to maintain habitat function, genetic diversity, and 
species viability (Service 1998a, p. 65). Further, it is identified as 
essential because the basin contains appropriate depth and ponding 
duration, soils, elevation, and water chemistry (pH, temperature, 
salinity, etc.), which fulfill Riverside fairy shrimp's life-history 
needs. This site has two vernal pools with confirmed Riverside fairy 
shrimp occupancy and which formed in depressions created by landslide-
like movements of the earth. These pools and Subunit 2h (described 
below) have been referred to as either earthen slumps, or ``sag'' 
pools. In addition, the federally endangered San Diego fairy shrimp co-
occurs within this subunit. Chiquita Ridge is within the San Juan Creek 
watershed and includes the perennial streams of Ca[ntilde]ada 
Gobernadora and Trabuco Creek. Radio Tower Road--Subunit 2g (see next 
subunit description)--is also within this watershed (Dudek and 
Associates 2001b). Proposed Subunit 2f contains the physical and 
biological features

[[Page 31712]]

essential to the conservation of Riverside fairy shrimp, including 
ephemeral wetland habitat (PCE 1), intermixed wetland and upland 
habitats that act as the local watershed (PCE 2), and the topography 
and soils that support ponding during winter and spring months (PCE 3).
    The physical and biological features essential to the conservation 
of the species in this subunit may require special management 
considerations or protection to address threats from nonnative plant 
species and anthropogenic activities, including, grazing, discing, and 
water quality degradation. Please see the Special Management 
Considerations or Protection section of this proposed rule for a 
discussion of the threats to Riverside fairy shrimp habitat and 
potential management considerations. We are considering this subunit 
for exclusion under 4(b)(2) of the Act; please see Exclusions section 
of this proposed rule for more information.
Subunit 2g: Radio Tower Road
    Subunit 2g is located in southern Orange County, California, east 
of Antonio Parkway, south/southwest of the Ortega Highway, and to the 
northwest of Trampas Canyon. Subunit 2g consists of 51 ac (21 ha) of 
privately owned land. Subunit 2g was not specifically identified in the 
1998 Recovery Plan (Appendix F), but is classified as necessary to 
stabilize and protect (conserve) existing populations of Riverside 
fairy shrimp within the ``Orange County Foothills (undescribed)'' 
heading in Appendix F (Service 1998a, p. F1).
    This subunit is considered essential for the recovery of Riverside 
fairy shrimp because it is currently occupied and includes one or more 
pools essential to maintain habitat function, genetic diversity, and 
species viability (Service 1998a, p. 65). Further, it is identified as 
essential because the basin contains appropriate depth and ponding 
duration, soils, elevation, and water chemistry (pH, temperature, 
salinity, etc.), which fulfill Riverside fairy shrimp's life-history 
needs. This site provides habitat for Riverside fairy shrimp as well as 
the federally endangered San Diego fairy shrimp. While this plan 
highlights the conservation value of the vernal pools at this site, the 
area has not yet been set aside as a preserve. One pool occurs at the 
northern end of the subunit, and a second pool occurs to the south. 
Subunit 2g contains the physical and biological features that are 
essential to the conservation of Riverside fairy shrimp, including 
ephemeral wetland habitat (PCE 1), intermixed wetland and upland 
habitats that act as the local watershed (PCE 2), and the topography 
and soils (Soper gravelly loams) that support ponding during winter and 
spring months (PCE 3).
    The physical and biological features essential to the conservation 
of the species in this subunit may require special management 
considerations or protection to address threats from nonnative plant 
species and anthropogenic activities (e.g., grazing and fire 
management). Please see the Special Management Considerations or 
Protection section of this proposed rule for a discussion of the 
threats to Riverside fairy shrimp habitat and potential management 
considerations. We are considering this subunit for exclusion under 
4(b)(2) of the Act; please see the Exclusions section of this proposed 
rule for more information.
Subunit 2h: San Onofre State Beach, State Park-Leased Lands
    Subunit 2h is located along the border shared between Orange and 
San Diego Counties, southeast of Richard Steed Memorial Park, and north 
of Christianitos Road. Nearly one-half of this proposed subunit (105 ac 
(42 ha)) occurs on Department of Defense (DOD) land on MCB Camp 
Pendleton and is determined exempt under section 4(a)(3)(B)(i) of the 
Act. Notwithstanding, Subunit 2h consists of 105 ac (42 ha) of 
federally owned (DOD) land and 107 ac (43 ha) of privately owned land. 
The portion of Subunit 2h which falls within DOD land, the ``Cal State 
Parks Lease'' as described in the 2007 INRMP (U.S. Marine Corp 2007, p. 
2-30) is part of a lease agreement made on September 1, 1971, for a 50-
year term. At one time, approximately 24,000 acres of land at Camp 
Pendleton was outleased for sheep grazing (U.S. Marine Corp 2007, p. 2-
29). Around 2003, all sheep grazing outleases were cancelled (U.S. 
Marine Corp 2007, p. 2-29). As the largest single leaseholder on the 
MCB Camp Pendleton, specific uses no longer include grazing but include 
within portions of Subunit 2h include: Military thoroughfares (roads), 
military training with advanced coordination, utility easements, fire 
suppression activities, and public recreation. Subunit 2h is a 
Riverside fairy shrimp location that was discovered after the 1993 
listing rule and 1998 Recovery Plan were written.
    This subunit is considered essential for the recovery of Riverside 
fairy shrimp because it is currently occupied and includes one or more 
pools essential to maintain habitat function, genetic diversity, and 
species viability (Service 1998a, p. 65). It represents an important 
ecological linkage for genetic exchange between the coastal mesa pools 
of San Diego and the Orange County Foothills occurrences. Further, it 
is identified as essential because the basin contains appropriate depth 
and ponding duration, soils, elevation, and water chemistry (pH, 
temperature, salinity, etc.), which fulfill Riverside fairy shrimp's 
life-history needs. Subunit 2h consists of two sag pools at the eastern 
section of the unit and its associated upland watersheds on land within 
Orange County near the City of San Clemente. Subunit 2h contains the 
physical and biological features that are essential to the conservation 
of Riverside fairy shrimp, including ephemeral wetland habitat (PCE 1), 
intermixed wetland and upland habitats that act as the local watershed 
(PCE 2), and the topography and soils that support ponding during 
winter and spring months (PCE 3).
    The physical and biological features essential to the conservation 
of the species in this subunit may require special management 
considerations or protection to address threats from nonnative plant 
species and anthropogenic activities (e.g., military activities, 
unauthorized recreational use, agricultural runoff, OHV use, and fire 
management). Please see the Special Management Considerations or 
Protection section of this proposed rule for a discussion of the 
threats to Riverside fairy shrimp habitat and potential management 
considerations. Essential habitat within the boundaries of Camp 
Pendleton has been exempted from critical habitat under section 
4(a)(3)(B)(i) of the Act.
Subunit 2i: SCE Viejo Conservation Bank
    Subunit 2i is located near the City of Lake Forest in southern 
Orange County, California. This subunit is bounded by Glenn Ranch Road 
to the north, El Toro Road to the southeast, and California Highway 241 
to the southwest. Subunit 2i consists of 63 ac (25 ha) of privately 
owned land. Subunit 2i was not specifically identified in the 1998 
Recovery Plan (Appendix F) but is classified as necessary to stabilize 
and protect (conserve) existing populations of Riverside fairy shrimp 
within the ``Orange County Foothills (undescribed)'' heading in 
Appendix F (Service 1998a, p. F1).
    This subunit is considered essential for the recovery of Riverside 
fairy shrimp because it is currently occupied and includes one or more 
pools essential to maintain habitat function, genetic diversity, and 
species viability (Service 1998a, p. 65). Further, it is

[[Page 31713]]

identified as essential because the basin contains appropriate depth 
and ponding duration, soils, elevation, and water chemistry (pH, 
temperature, salinity, etc.), which fulfill Riverside fairy shrimp's 
life-history needs. Subunit 2i contains the physical and biological 
features that are essential to the conservation of Riverside fairy 
shrimp, including ephemeral wetland habitat (PCE 1), intermixed wetland 
and upland habitats that act as the local watershed (PCE 2), and the 
topography and soils that support ponding during winter and spring 
months (PCE 3).
    The physical and biological features essential to the conservation 
of the species in this subunit may require special management 
considerations or protection to address threats from nonnative plant 
species and anthropogenic activities (e.g., development, unauthorized 
recreational use, OHV use, and fire management). Please see the Special 
Management Considerations or Protection section of this proposed rule 
for a discussion of the threats to Riverside fairy shrimp habitat and 
potential management considerations. We are considering this subunit 
for exclusion under 4(b)(2) of the Act; please see the Exclusions 
section of this proposed rule for more information.
Unit 3: Riverside County Inland Valleys
    Unit 3 is located in western Riverside County, California, and 
consists of 6 subunits totaling 865 ac (350 ha). This unit contains 54 
ac (22 ha) of State land and 811 ac (328 ha) of private land. These 
totals do not include lands formerly identified in 2005 as essential 
within March Air Reserve Base (3b; 101 ac (41 ha)) and inside the 
Pechanga Band of Luise[ntilde]o Mission Indians reservation (6 ac (2 
ha)) near the City of Temecula. These areas have been removed from this 
proposed revised designation (see Summary of Changes from Previously 
Designated Critical Habitat section of this rule). This unit contains 
natural vernal pool complexes, detention ponds, and created (enhanced) 
ephemeral basins included within the general vicinity of the Back Basin 
of Lake Elsinore, pools north and east of the City of Murrieta, and 
pools on Mesa de Colorado atop the Santa Rosa Plateau. The six subunits 
contained within Unit 3 are: Australia Pool, Scott Road Pool, 
Schleuniger Pool, Skunk Hollow, and Field Pool (also known as Barry 
Jones Wetland Mitigation Bank) (all previously identified as essential 
but excluded under section 4(b)(2) in 2005) (Service 2005, p. 19195); 
Johnson Ranch Created Pools; and two recently discovered Riverside 
fairy shrimp occupied pools on Mesa de Colorado atop Santa Rosa Plateau 
(Selheim and Searcy 2010, p. 97).
    Vernal pool and pool complexes in this unit are generally isolated 
to a degree from maritime influence, are greater than approximately 8 
mi (15 km) in distance from the coast, and are representative of pools 
with alluvial or volcanic (basalt) soil types. Riverside fairy shrimp 
populations in this unit occur at the eastern limit of occupied habitat 
for Riverside fairy shrimp within the species' known range. The pools 
contain the primary constituent elements described above relating to 
ponding, consist of functionally intact watersheds, and possess 
appropriate underlying soil substrates (Los Posas loam, Los Posas rocky 
loam, Murrieta stony clay loam, Wyman loam, and Fallbrook rocky sandy 
loam) and appropriate topography and hydrology. Riverside County pools 
also are at the highest of all elevations among occupied pools for 
Riverside fairy shrimp, ranging from 385 m to 633 m (1,265 ft to 2,076 
ft). All subunits within Riverside County are within the Western 
Riverside MSHCP.
    Because Unit 3 occurs in an inland valley, and consists mainly of 
isolated pools (with the exception of the Santa Rosa Plateau) rather 
than the larger vernal pool complexes on coastal mesas, pools in this 
unit generally have larger watersheds and therefore represent a unique 
function and type of vernal pool habitat when compared to the other 
units. All subunits within this unit are known to be occupied, some 
recently documented (since 2005), including two pools recently 
confirmed as occupied by Riverside fairy shrimp on the Santa Rosa 
Plateau during a 2009 survey (Selheim and Searcy 2010, p. 98). This 
unit supports vernal pool complexes with several plant and animal 
genera endemic to California vernal pool habitats, including the 
federally endangered Orcuttia californica, Pogogyne abramsii (San Diego 
mesa mint), and vernal pool fairy shrimp (Branchinecta lynchi).
Subunit 3c: Australia Pool
    Subunit 3c is located in the City of Lake Elsinore, northwest of 
Sedco Hills, in western Riverside County, California. This subunit is 
west of Interstate 15 and north of the Links at Summerly golf course, 
near the southeastern shore of Lake Elsinore. Subunit 3c consists of 19 
ac (8 ha) of privately owned land. Subunit 3c was not identified in the 
1998 Recovery Plan (Appendix F) (Service 1998a, p. F1). The pool is 
located in an area that has been graded, is approximately 0.94 acre 
(less than 1 ha) in size and 20 in (25.4 cm) deep, and is considered to 
be an artificially modified vernal pool (CNDDB, September 21, 2010).
    This subunit is considered essential for the conservation of 
Riverside fairy shrimp because it was occupied at the time of listing 
and is currently occupied and includes one or more pools essential to 
maintain habitat function, genetic diversity, and species viability 
(Service 1998a, p. 65). Further, it is essential because the basin 
contains appropriate depth and ponding duration, soils, elevation, and 
water chemistry (pH, temperature, salinity, etc.), which fulfill 
Riverside fairy shrimp's life-history needs. Subunit 3c contains the 
physical and biological features that are essential to the conservation 
of Riverside fairy shrimp, including ephemeral wetland habitat (PCE 1), 
intermixed wetland and upland habitats that act as the local watershed 
(PCE 2), and the topography and soils that support ponding during 
winter and spring months (PCE 3).
    The physical and biological features essential to the conservation 
of the species in this subunit may require special management 
considerations or protection to address threats from nonnative plant 
species and anthropogenic activities (e.g., potential development, 
altered hydrology, OHV use, and water quality impacts). Please see the 
Special Management Considerations or Protection section of this 
proposed rule for a discussion of the threats to Riverside fairy shrimp 
habitat and potential management considerations. We are considering 
this subunit for exclusion under 4(b)(2) of the Act; please see 
Exclusions section of this proposed rule for more information.
Subunit 3d: Scott Road Pool
    Subunit 3d is located in the City of Menifee in western Riverside 
County, California. This subunit is in the lot northeast of the 
intersection between Haleblain Road and Scott Road. Subunit 3d consists 
of 9 ac (4 ha) of privately owned land. Subunit 3d was not identified 
in the 1998 Recovery Plan (Appendix F) (Service 1998a, p. F1) as 
essential to the conservation of the species, because Subunit 3d had 
not been surveyed at the time it was written. However, this subunit was 
occupied at the time of listing and is currently occupied.
    This subunit is considered essential for the recovery of Riverside 
fairy shrimp because it includes one or more pools essential to 
maintain habitat function, genetic diversity, and species viability 
(Service 1998a, p. 65). Further,

[[Page 31714]]

it is essential because the basin contains appropriate depth and 
ponding duration, soils, elevation, and water chemistry (pH, 
temperature, salinity, etc.), which fulfill Riverside fairy shrimp's 
life-history needs. Subunit 3d contains the physical and biological 
features that are essential to the conservation of Riverside fairy 
shrimp, including ephemeral wetland habitat (PCE 1), intermixed wetland 
and upland habitats that act as the local watershed (PCE 2), and the 
topography and soils that support ponding during winter and spring 
months (PCE 3).
    The physical and biological features essential to the conservation 
of the species in this subunit may require special management 
considerations or protection to address threats from nonnative plant 
species, agricultural activities, and residential/commercial 
development that occur in the vernal pool basins. Please see the 
Special Management Considerations or Protection section of this 
proposed rule for a discussion of the threats to Riverside fairy shrimp 
habitat and potential management considerations. We are considering 
this subunit for exclusion under 4(b)(2) of the Act; please see 
Exclusions section of this proposed rule for more information.
Subunit 3e: Schleuniger Pool
    Subunit 3e is located in the City of Wildomar in western Riverside 
County, California. This subunit is bounded by Meadow Park Circle on 
the west and La Estrella Street to the south. Subunit 3e consists of 23 
ac (9 ha) of privately owned land. Subunit 3e was not identified in the 
1998 Recovery Plan (Appendix F) (Service 1998a, p. F1) as essential to 
the conservation of the species, because Subunit 3e had not been 
surveyed at the time it was written. However, this subunit was occupied 
at the time of listing and is currently occupied.
    This subunit is considered essential for the recovery of Riverside 
fairy shrimp because it includes one or more pools essential to 
maintain habitat function, genetic diversity, and species viability 
(Service 1998a, p. 65). Further, it is essential because the basin 
contains appropriate depth and ponding duration, soils, elevation, and 
water chemistry (pH, temperature, salinity, etc.), which fulfill 
Riverside fairy shrimp's life-history needs. This vernal pool complex 
occurred naturally, but has been degraded from residential development 
and associated water discharge from surrounding properties. Subunit 3e 
contains the physical and biological features that are essential to the 
conservation of Riverside fairy shrimp, including ephemeral wetland 
habitat (PCE 1), intermixed wetland and upland habitats that act as the 
local watershed (PCE 2), and the topography and soils that support 
ponding during winter and spring months (PCE 3).
    The physical and biological features essential to the conservation 
of the species in this subunit may require special management 
considerations or protection to address threats from nonnative plant 
species and anthropogenic activities (e.g., residential water run-off 
and fire management). Please see the Special Management Considerations 
or Protection section of this proposed rule for a discussion of the 
threats to Riverside fairy shrimp habitat and potential management 
considerations. We are considering this subunit for exclusion under 
4(b)(2) of the Act; please see Exclusions section of this proposed rule 
for more information.
Subunit 3f: Skunk Hollow and Field Pool (Barry Jones Wetland Mitigation 
Bank)
    Subunit 3f is located in the City of Temecula in western Riverside 
County, California. This subunit is east of California Highway 79 and 
bounded by Murrieta Hot Springs Road to the south, Pourroy Road to the 
west, Bella Vista Sports Field off of Browning Street to the north, and 
Beeler Road to the east. Subunit 3f consists of 163 ac (66 ha) of 
privately owned land. Subunit 3f includes the Barry Jones Wetland 
Mitigation Bank, which comprises 140 acres (the 33-acre Skunk Hollow 
Pool and 107 acres of the pool's watershed). The Barry Jones Wetland 
Mitigation Bank was established in 1997 to serve as off-site 
compensatory mitigation for unavoidable impacts to wetland habitats 
(Center for Natural Lands Management 1997).
    Subunit 3f contains areas identified in the 1998 Recovery Plan 
(Appendix F) as necessary to stabilize and protect (conserve) existing 
populations of Riverside fairy shrimp, as well as other proposed and 
listed vernal pool species. This subunit was occupied at the time of 
listing and is currently occupied.
    This subunit is considered essential for the recovery of Riverside 
fairy shrimp because it includes one or more pools essential to 
maintain habitat function, genetic diversity, and species viability 
(Service 1998a, p. 65). Further, it is essential because the basin 
contains appropriate depth and ponding duration, soils, elevation, and 
water chemistry (pH, temperature, salinity, etc.), which fulfill 
Riverside fairy shrimp's life-history needs. The isolated pool at Skunk 
Hollow is a relatively large (up to 10 ac (4 ha)) pool, verging upon a 
vernal lake. It may remain wet through much of the year and only 
contain vernal pool plant species on its drying margins. This pool is 
the largest valley vernal pool remaining in all of southern California 
(Eriksen and Belk 1999, p. 104). This pool represents a set of physical 
(hydrological), ecological, and biological factors (including a unique 
vegetation assemblage) that make this pool different from other vernal 
pools in the species' range. Its habitat consists of a seasonally 
astatic (directionally changing) swale pool, deepened somewhat by 
excavation and located in a thin strip of disturbed coastal sage scrub 
and grassland vegetation (CNDDB 2010). It contains the physical and 
biological features that are essential to the conservation of Riverside 
fairy shrimp, including ephemeral wetland habitat (PCE 1), intermixed 
wetland and upland habitats that act as the local watershed (PCE 2), 
and the topography and soils (Willows silty clay) that support ponding 
during winter and spring months (PCE 3).
    The physical and biological features essential to the conservation 
of the species in this subunit may require special management 
considerations or protection to address threats from nonnative plant 
species and anthropogenic activities (e.g., residential and commercial 
development, unauthorized recreational use, OHV use, and fire 
management). Please see the Special Management Considerations or 
Protection section of this proposed rule for a discussion of the 
threats to Riverside fairy shrimp habitat and potential management 
considerations. We are considering this subunit for exclusion under 
4(b)(2) of the Act; please see Exclusions section of this proposed rule 
for more information.
Subunit 3g: Johnson Ranch Created Pools
    Subunit 3g is located in the City of Temecula in western Riverside 
County, California. This subunit is approximately 1 mi (1.5 km) east of 
Subunit 3f and approximately 0.75 mi (1.25 km) south of Borel Road. 
Subunit 3g consists of 54 ac (22 ha) of State-owned land. Subunit 3g 
was not identified in the 1998 Recovery Plan (Appendix F) (Service 
1998a, p. F1) because occupancy was established for Riverside fairy 
shrimp after the Recovery Plan was written.
    This vernal pool complex is a Service-approved vernal pool 
restoration site created in January 2001. Seven basins (approximately 2 
ac (0.8 ha) and a surrounding watershed of approximately 12 ac (5 ha)) 
were created to avoid permanent loss of the Riverside

[[Page 31715]]

fairy shrimp population at the Redhawk development (located in 
Temecula) and to offset adverse effects to Riverside fairy shrimp 
associated with grading, construction, and maintenance of the Redhawk 
residential development project. This subunit is considered essential 
to conservation and recovery of Riverside fairy shrimp because it is 
currently occupied; is located in a larger intact watershed free of 
adjacent commercial or residential development; includes one or more 
pools essential to maintain habitat function, genetic diversity, and 
species viability (Service 1998a, p. 65); represents an important 
historic population with a high baseline fairy shrimp density (at 
Redhawk properties) we determined was necessary to ``provide[s] for 
long-term conservation of Riverside fairy shrimp and contribute[s] to 
an ongoing regional conservation effort, for the long-term survival of 
this endangered species'' (Service 2001b, p. 11).
    We are considering this subunit for exclusion under 4(b)(2) of the 
Act; please see Exclusions section of this proposed rule for more 
information.
Subunit 3h: Santa Rosa Plateau--Mesa de Colorado
    Subunit 3h is located on the Santa Rosa Plateau near the City of 
Murrieta in western Riverside County, California. This subunit is east/
northeast of the intersection between Via Volcano and Avocado Mesa 
roads. Subunit 3h consists of 597 ac (242 ha) of privately owned land; 
more than half of the land (348 ac (141 ha)) is owned and conserved by 
The Nature Conservancy within the Santa Rosa Plateau Ecological 
Reserve. Subunit 3h contains areas identified in the 1998 Recovery Plan 
(Appendix F) as necessary to stabilize and protect (conserve) existing 
populations of Riverside fairy shrimp, as well as other proposed and 
listed vernal pool species. The Santa Rosa Plateau pools are variable 
in size, ranging up to about 10 ac (4 ha) (vernal lake) and occur on 
the Mesa de Colorado and adjacent mesas on basalt (volcanic) flows. 
There are fewer than a dozen of these pools Statewide (Keeler-Wolf et 
al. 1998, p. 77).
    This subunit is considered essential for the recovery of Riverside 
fairy shrimp because it is the last representative pool on the Southern 
Basalt Flow; it was occupied at the time of listing; is currently 
occupied; and it includes one or more pools essential to maintain 
habitat function, genetic diversity and species viability (Service 
1998a, p. 65). Further, it is essential because the basin contains 
appropriate depth and ponding duration, clay-loam soils over granitic 
substrate, elevation, and water chemistry (pH, temperature, salinity, 
etc.), which fulfill Riverside fairy shrimp's life-history needs. Land 
within this subunit contain Las Posas loam, Ramona sandy loam, Willows 
silty clay, and Wyman loam soil series, and vegetation consists 
primarily of annual and needlegrass grassland and vernal pool habitats. 
Subunit 3h contains the physical and biological features that are 
essential to the conservation of Riverside fairy shrimp: Clay loam soil 
series underlain by heavy clay loams or clays derived from olivine 
basalt lava flows that generally occur on mesas and gentle to moderate 
slopes (2 to 15 percent slopes) (i.e., PCE 1, 3) and areas with a 
natural, generally intact surface and subsurface soil structure that 
support Riverside fairy shrimp (PCE 2). Subunit 3h supports a stable 
occurrence of Riverside fairy shrimp, provides potential connectivity 
between occurrences of Riverside fairy shrimp, supports a unique 
habitat type, and is at the highest elevation for Riverside fairy 
shrimp occupied pools throughout the species' range (2,076 ft (633 m)). 
Because these pools occur on an expansive mesa at higher altitude, they 
generally also have much larger watersheds for pool size, and represent 
a physically, ecologically, and genetically unique assemblage essential 
to the long-term conservation of the species. This unit also supports 
the federally endangered Orcuttia californica and supports the 
southernmost population of the vernal pool fairy shrimp.
    The physical and biological features essential to the conservation 
of the species in this subunit may require special management 
considerations or protection to address threats from nonnative plant 
species and anthropogenic activities (e.g., grazing, unauthorized 
recreational use, OHV use, fire management, and water quality 
discharge). Please see the Special Management Considerations or 
Protection section of this rule for a discussion of the threats to 
Riverside fairy shrimp habitat and potential management considerations. 
We are considering this subunit for exclusion under 4(b)(2) of the Act; 
please see Exclusions section of this proposed rule for more 
information.
Unit 4: San Diego Northern Coastal Mesa and Central Coastal Mesa 
Management Unit
    Unit 4 is located in north and central coastal San Diego County, 
and includes vernal pools associated with coastal terraces north of the 
San Dieguito River (i.e., northern Coastal Mesa Management Unit, 
including MCB Camp Pendleton and the City of Carlsbad) and the coastal 
terraces and mesa of central San Diego County from the San Dieguito 
River south to San Diego Bay and north of the Sweetwater River (Central 
Coastal Mesa Management Unit; see Service 1998a, p. 43).
    Within Unit 4, eight areas on MCB Camp Pendleton and one area on 
MCAS Miramar identified as essential habitat are exempt from this 
proposed revised critical habitat designation. These MCB Camp Pendleton 
areas are exempt under section 4(a)(3)(B)(i) of the Act because they 
are covered by the 2007 integrated natural resources management plan 
(INRMP), which provides a benefit to Riverside fairy shrimp (see 
Exemptions section of this proposed rule for a detailed discussion). 
MCB Camp Pendleton has several large vernal pool complexes that support 
Riverside fairy shrimp. Land exempt (1,929 ac (780 ha)) from critical 
habitat designation on MCB Camp Pendleton includes: San Onofre State 
Beach, State Park-leased lands, near Christianitos Creek foothills 
(along the northwest corner of MCB Camp Pendleton); area south of San 
Onofre State Beach, in Uniform Training Area; Las Pulgas North; Las 
Pulgas East; Las Pulgas West; Cockleburr North; Cockleburr South; and 
Stuart Mesa. All these pool complexes occur within the San Diego North 
Coastal Mesas Management Area as identified in the 1998 Recovery Plan.
    Also exempt from this proposed revised critical habitat are the 
vernal pools within the San Diego Central Coastal Mesa Management Area, 
as identified in the 1998 Recovery Plan, which contains 59 ac (24 ha) 
of land, all on MCAS Miramar. MCAS Miramar is exempt in this proposed 
revised critical habitat designation for Riverside fairy shrimp under 
section 4(a)(3)(B)(i) of the Act because MCAS Miramar has completed an 
INRMP (U.S. Marine Corps 2006) that provides a benefit to Riverside 
fairy shrimp (see the Exemptions section of this proposed rule for a 
detailed discussion).
Subunit 4c: Poinsettia Lane Commuter Train Station
    Subunit 4c is located adjacent to the City of Carlsbad in San Diego 
County, California. This subunit is loosely bounded by Avenida Encinas 
on the north, a housing development on the east, Poinsettia Lane on the 
south, and train tracks to the west. Subunit 4c consists of 
approximately 9 ac (3 ha) that contains 6 ac (2 ha) of public land 
owned by the North County Transit District, and 3 ac (1 ha) of private 
land.

[[Page 31716]]

    Subunit 4c contains areas identified in the 1998 Recovery Plan 
(Appendix F) as necessary to stabilize and protect (conserve) existing 
populations of Riverside fairy shrimp, as well as other proposed and 
listed vernal pool species.
    The subunit includes one or more pools essential to maintain 
habitat function, genetic diversity, and species viability (Service 
1998a, p. 65). Further, it is identified as essential because the basin 
contains appropriate depth and ponding duration, soils, elevation, and 
water chemistry (pH, temperature, salinity, etc.), which fulfill 
Riverside fairy shrimp's life-history needs. Subunit 4c is an isolated 
habitat, representative of a unique type of vernal pool that no longer 
has extensive distribution. This vernal pool, north of San Dieguito 
River in San Diego County, and adjacent to the Poinsettia Lane Commuter 
Station in the City of Carlsbad, is representative of the last 
remaining coastal terrace vernal pool basin, with the exception of some 
vernal pool complexes located on MCB Camp Pendleton. The Poinsettia 
Lane vernal pools represent the most coastal location where the San 
Diego fairy shrimp and the Riverside fairy shrimp co-occur. Because 
this complex is associated with a remnant of coastal terrace habitat, 
has a unique community assemblage, and is one of the last remaining 
coastal occurrences of Riverside fairy shrimp, it is considered 
essential for the conservation of the species. The Poinsettia Lane 
vernal pool complex consists of a series of vernal pools that run 
parallel to a berm created by the train tracks. Subunit 4c contains the 
primary constituent elements relating to the pooling basins, 
watersheds, underling soil substrate and topography. Subunit 4c 
contains the physical and biological features that are essential to the 
conservation of Riverside fairy shrimp including ephemeral wetland 
habitat (PCE 1), intermixed wetland and upland habitats that act as the 
local watershed (PCE 2), and the topography and soils that support 
ponding during winter and spring months (PCE 3).
    The physical and biological features essential to the conservation 
of the species in this subunit may require special management 
considerations or protection to address threats from nonnative plant 
species and activities (e.g., unauthorized recreational use and water 
quality discharge). Please see the Special Management Considerations or 
Protection section of this proposed rule for a discussion of the 
threats to Riverside fairy shrimp habitat and potential management 
considerations. We are considering this subunit for exclusion under 
4(b)(2) of the Act; please see Exclusions section of this proposed rule 
for more information.
Unit 5: San Diego Southern Coastal Mesas
    Unit 5 is located in Southern San Diego County and consists of 
eight subunits totaling 925 ac (375 ha). This unit contains 40 ac (16 
ha) of federally owned land, 256 ac (104 ha) of State-owned land, 157 
ac (64 ha) of locally owned land, and 472 ac (191 ha) of private land. 
This unit falls within the San Diego Southern Coastal Management Area, 
as identified in the 1998 Recovery Plan. Land proposed as critical 
habitat includes vernal pool complexes within the jurisdictions of the 
Service, City of San Diego, County of San Diego, Department of Homeland 
Security (Border Crossing, formerly INS), other DOD land, and private 
interests. This unit contains several mesa-top vernal pool complexes on 
western Otay Mesa (Bauder vernal pool complexes J2 N, J2 S, J2 W, J4, 
J5, J11 W, J11 E, J12, J15, J16-18, J33) and eastern Otay Mesa (Bauder 
pool complexes J29-31, and J33) as in Appendix D of City of San Diego 
(2004). These vernal pool complexes are associated with coastal mesas 
from the Sweetwater River south to the U.S.-Mexico International Border 
and represent the southern-most occurrences of Riverside fairy shrimp 
in the United States. This unit also contains most of the species' 
genetic diversity based on rangewide analyses, with Otay Mesa pools 
being significantly differentiated from one another (Lahti et al. 2010, 
p. 19). This area is essential to the conservation of the Riverside 
fairy shrimp for the following reasons: (1) These vernal pool complexes 
represent the few remaining examples of the much larger and mostly 
extirpated vernal pool complexes on the highly urbanized Otay Mesa 
(Bauder 1986); (2) recent genetic work indicates that complexes within 
this unit (J26, and J29-30) support Riverside fairy shrimp with a 
unique haplotype (B); and (3) it is only one of three locations that 
supports haplotype C (Lahti et al. 2010). Maintaining this unique 
genetic structure may be crucial in the conservation of this species.
Subunit 5a: Sweetwater (J33)
    Subunit 5a is located in the City of San Diego in southern San 
Diego County, California. This subunit is at Sweetwater High School 
(site J33), south of the intersection between Otay Mesa and Airway 
roads. Subunit 5a consists of 2 ac (<1 ha) of locally owned land and <1 
ac (0 ha) of private land. Subunit 5a contains areas identified in the 
1998 Recovery Plan (Appendix F) as necessary to stabilize and protect 
(conserve) existing populations of Riverside fairy shrimp, as well as 
other proposed and listed vernal pool species.
    This subunit is considered essential for the recovery of Riverside 
fairy shrimp because it includes one or more pools essential to 
maintain habitat function, genetic diversity, and species viability 
(Service 1998a, p. 65). Further, it is essential because the basin 
contains appropriate depth and ponding duration, soils, elevation, and 
water chemistry (pH, temperature, salinity, etc.), which fulfill 
Riverside fairy shrimp's life-history needs. This subunit is under the 
jurisdiction of the Sweetwater Union High School District. Subunit 5a 
contains the physical and biological features that are essential to the 
conservation of Riverside fairy shrimp, including ephemeral wetland 
habitat (PCE 1), intermixed wetland and upland habitats that act as the 
local watershed (PCE 2), and the topography and soils (Olivenhain 
cobbly loam soil series) that support ponding during winter and spring 
months (PCE 3).
    The physical and biological features essential to the conservation 
of the species in this subunit may require special management 
considerations or protection to address threats from nonnative plant 
species and anthropogenic activities (e.g., unauthorized recreational 
use and OHV use). Please see the Special Management Considerations or 
Protection section of this proposed rule for a discussion of the 
threats to Riverside fairy shrimp habitat and potential management 
considerations.
Subunit 5b: Arnie's Point (J15)
    Subunit 5b is located in the Otay Mesa region of southern San Diego 
County, California. This subunit is bounded by the U.S.-Mexico 
International Border to the south and a warehouse at the end of Calle 
de Linea to the east. Subunit 5b consists of 29 ac (12 ha) of federally 
owned land. Subunit 5b was not specifically identified in the 1998 
Recovery Plan (Appendix F), but is classified as necessary to stabilize 
and protect (conserve) existing populations of Riverside fairy shrimp 
within the ``J2, J5, J7, J11-21, J23-30 Otay Mesa'' heading in Appendix 
F (Service 1998a, p. F1).
    This subunit is considered essential for the recovery of Riverside 
fairy shrimp because it includes one or more pools essential to 
maintain habitat function, genetic diversity, and species viability 
(Service 1998a, p. 65). Further, it is essential because the basin 
contains

[[Page 31717]]

appropriate depth and ponding duration, soils, elevation, and water 
chemistry (pH, temperature, salinity, etc.), which fulfill Riverside 
fairy shrimp's life-history needs. Subunit 5b supports a stable 
occurrence of Riverside fairy shrimp and provides potential 
connectivity between occurrences of Riverside fairy shrimp in northern 
Mexico and southern San Diego. Subunit 5b contains the physical and 
biological features that are essential to the conservation of Riverside 
fairy shrimp, including ephemeral wetland habitat (PCE 1), intermixed 
wetland and upland habitats that act as the local watershed (PCE 2), 
and the topography and soils that support ponding during winter and 
spring months (PCE 3).
    The physical and biological features essential to the conservation 
of the species in this subunit may require special management 
considerations or protection to address threats from nonnative plant 
species and activities (e.g., military exercises and OHV use). Please 
see the Special Management Considerations or Protection section of this 
proposed rule for a discussion of the threats to Riverside fairy shrimp 
habitat and potential management considerations.
Subunit 5c: East Otay Mesa
    Subunit 5c is located in the eastern Otay Mesa region of southern 
San Diego County, California. This subunit is approximately 1.75 mi 
(2.75 km) southeast of Kuebler Ranch and just north of the U.S.-Mexico 
International Border. Subunit 5c consists of 57 ac (23 ha) of privately 
owned land. These lands fall within the County of San Diego Subarea 
Plan under the San Diego MSCP. Subunit 5c was not specifically 
identified in the 1998 Recovery Plan (Appendix F), but is classified as 
necessary to stabilize and protect (conserve) existing populations of 
Riverside fairy shrimp within the ``J2, J5, J7, J11-21, J23-30 Otay 
Mesa'' heading in Appendix F (Service 1998a, p. F1). This subunit was 
occupied at the time of listing and is currently occupied.
    This subunit is considered essential for the recovery of Riverside 
fairy shrimp because it includes one or more pools essential to 
maintain habitat function, genetic diversity, and species viability 
(Service 1998a, p. 65). Further, it is essential because the basin 
contains appropriate depth and ponding duration, soils, elevation, and 
water chemistry (pH, temperature, salinity, etc.), which fulfill 
Riverside fairy shrimp's life-history needs. The vernal pool in this 
subunit has been impacted by off-road vehicle use, cattle grazing, and 
nonnative grasses. Subunit 5c contains the physical and biological 
features that are essential to the conservation of Riverside fairy 
shrimp, including ephemeral wetland habitat (PCE 1), intermixed wetland 
and upland habitats that act as the local watershed (PCE 2), and the 
topography and soils that support ponding during winter and spring 
months (PCE 3).
    The physical and biological features essential to the conservation 
of the species in this subunit may require special management 
considerations or protection to address threats from nonnative plant 
species and anthropogenic activities (e.g., development, OHV use, water 
run-off, and grazing). Please see the Special Management Considerations 
or Protection section of this proposed rule for a discussion of the 
threats to Riverside fairy shrimp habitat and potential management 
considerations.
Subunit 5d: J29-31
    Subunit 5d is located in the Otay Mesa region of southern San Diego 
County, California. This subunit is to the east and west of California 
Highway 125, south of the Otay Valley, and north of the U.S.-Mexico 
International Border. Subunit 5d consists of less than 1 ac (0 ha) of 
federally owned land, 211 ac (85 ha) of State-owned lands (Caltrans), 
and 159 ac (64 ha) of private land. Subunit 5d was not specifically 
identified in the 1998 Recovery Plan (Appendix F), but is classified as 
necessary to stabilize and protect (conserve) existing populations of 
Riverside fairy shrimp within the ``J2, J5, J7, J11-21, J23-30 Otay 
Mesa'' heading in Appendix F (Service 1998a, p. F1). This subunit was 
occupied at the time of listing and is currently occupied.
    This subunit is considered essential for the recovery of Riverside 
fairy shrimp because it includes one or more pools essential to 
maintain habitat function, genetic diversity, and species viability 
(Service 1998a, p. 65). Further, it is essential because the basin 
contains appropriate depth and ponding duration, soils, elevation, and 
water chemistry (pH, temperature, salinity, etc.), which fulfill 
Riverside fairy shrimp's life-history needs. Subunit 5d is 
predominantly in the City of San Diego in San Diego County, California, 
although portions of pools J29-31 are within the County of San Diego's 
jurisdiction. This subunit contains a large area of habitat that 
supports sizable occurrences of Riverside fairy shrimp and provides 
potential connectivity between occurrences of Riverside fairy shrimp in 
Subunits 5e and 5c. This subunit contains several mesa-top vernal pool 
complexes on eastern Otay Mesa (Bauder vernal pool complexes J22, J29, 
J30, J31 N, J31 S as in Appendix D of City of San Diego, 2004, and 
Service GIS). Subunit 5d contains the physical and biological features 
that are essential to the conservation of Riverside fairy shrimp, 
including ephemeral wetland habitat (PCE 1), intermixed wetland and 
upland habitats that act as the local watershed (PCE 2), and the 
topography and soils that support ponding during winter and spring 
months (PCE 3).
    The physical and biological features essential to the conservation 
of the species in this subunit may require special management 
considerations or protection to address threats from nonnative plant 
species and anthropogenic activities (e.g., OHV use, unauthorized 
recreational use, impacts from development (including water run-off), 
and fire management). Please see the Special Management Considerations 
or Protection section of this proposed rule for a discussion of the 
threats to Riverside fairy shrimp habitat and potential management 
considerations.
    We are considering a portion of this subunit for exclusion under 
4(b)(2) of the Act; please see Exclusions section of this proposed rule 
for more information.
Subunit 5e: J2 N, J4, J5 (Robinhood Ridge)
    Subunit 5e is located in the Otay Mesa region of southern San Diego 
County, California. This subunit is approximately 1 mi (1.5 km) east of 
Ocean View Hills Parkway, 0.6 mi (1 km) north of California Highway 
905, and bounded by Vista Santo Domingo to the east. Subunit 5e 
consists of 32 ac (13 ha) of locally owned land and 12 ac (5 ha) of 
private land. Subunit 5e was not specifically identified in the 1998 
Recovery Plan (Appendix F), but is classified as necessary to stabilize 
and protect (conserve) existing populations of Riverside fairy shrimp 
within the ``J2, J5, J7, J11-21, J23-30 Otay Mesa'' heading in Appendix 
F (Service 1998a, p. F1). This subunit was occupied at the time of 
listing and is currently occupied.
    This subunit is considered essential for the recovery of Riverside 
fairy shrimp because it includes one or more pools essential to 
maintain habitat function, genetic diversity, and species viability 
(Service 1998a, p. 65). Further, it is essential because the basin 
contains appropriate depth and ponding duration, soils, elevation, and 
water chemistry (pH, temperature, salinity, etc.), which fulfill 
Riverside fairy shrimp's life-history needs. Subunit 5e contains the 
physical and biological features that are essential to the

[[Page 31718]]

conservation of Riverside fairy shrimp, including ephemeral wetland 
habitat (PCE 1), intermixed wetland and upland habitats that act as the 
local watershed (PCE 2), and the topography and soils that support 
ponding during winter and spring months (PCE 3).
    The physical and biological features essential to the conservation 
of the species in this subunit may require special management 
considerations or protection to address threats from nonnative plant 
species and anthropogenic activities (e.g., OHV use, unauthorized 
recreational use, impacts from development, and fire management). 
Please see the Special Management Considerations or Protection section 
of this proposed rule for a discussion of the threats to Riverside 
fairy shrimp habitat and potential management considerations.
Subunit 5f: J2 W and J2 S (Hidden Trails, Cal Terraces, and Otay Mesa 
Road)
    Subunit 5f is located in the Otay Mesa region of southern San Diego 
County, California, and consists of three pool complexes. All complexes 
are located north of California Highway 905 and southwest of subunit 
5e, with one complex in the lot southwest of Ocean View Hills Parkway, 
one bounded to the west by Hidden Trails Road, and one bounded by 
Corporate Center Drive to the west. Subunit 5f consists of 22 ac (9 ha) 
locally owned land and 11 ac (4 ha) of private land. Subunit 5f was not 
specifically identified in the 1998 Recovery Plan (Appendix F), but is 
classified as necessary to stabilize and protect (conserve) existing 
populations of Riverside fairy shrimp within the ``J2, J5, J7, J11-21, 
J23-30 Otay Mesa'' heading in Appendix F (Service 1998a, p. F1). This 
subunit was occupied at the time of listing and is currently occupied.
    This subunit is considered essential for the recovery of Riverside 
fairy shrimp because it includes one or more pools essential to 
maintain habitat function, genetic diversity, and species viability 
(Service 1998a, p. 65). Further, it is essential because the basin 
contains appropriate depth and ponding duration, soils, elevation, and 
water chemistry (pH, temperature, salinity, etc.), which fulfill 
Riverside fairy shrimp's life-history needs. Subunit 5f contains the 
physical and biological features that are essential to the conservation 
of Riverside fairy shrimp, including ephemeral wetland habitat (PCE 1), 
intermixed wetland and upland habitats that act as the local watershed 
(PCE 2), and the topography and soils that support ponding during 
winter and spring months (PCE 3).
    The physical and biological features essential to the conservation 
of the species in this subunit may require special management 
considerations or protection to address threats from nonnative plant 
species and anthropogenic activities (e.g., OHV use; unauthorized 
recreational use; impacts from development, including water run-off; 
and fire management). Please see the Special Management Considerations 
or Protection section of this proposed rule for a discussion of the 
threats to Riverside fairy shrimp habitat and potential management 
considerations.
Subunit 5g: J14
    Subunit 5g is located in the Otay Mesa region of southern San Diego 
County, California. This subunit is south of California Highway 905, 
southeast of Caliente Avenue, west of Heritage Road, and northwest of 
Spring Canyon. Subunit 5g consists of 45 ac (18 ha) of State-owned land 
(Caltrans), 18 ac (7 ha) of locally owned land, and 72 ac (29 ha) of 
private land. Subunit 5g was not specifically identified in the 1998 
Recovery Plan (Appendix F), but is classified as necessary to stabilize 
and protect (conserve) existing populations of Riverside fairy shrimp 
within the ``J2, J5, J7, J11-21, J23-30 Otay Mesa'' heading in Appendix 
F (Service 1998a, p. F1). This subunit was occupied at the time of 
listing and is currently occupied.
    This subunit is considered essential for the recovery of Riverside 
fairy shrimp because it includes one or more pools essential to 
maintain habitat function, genetic diversity, and species viability 
(Service 1998a, p. 65). Further, it is essential because the basin 
contains appropriate depth and ponding duration, soils, elevation, and 
water chemistry (pH, temperature, salinity, etc.), which fulfill 
Riverside fairy shrimp's life-history needs. Subunit 5g contains the 
physical and biological features that are essential to the conservation 
of Riverside fairy shrimp, including ephemeral wetland habitat (PCE 1), 
intermixed wetland and upland habitats that act as the local watershed 
(PCE 2), and the topography and soils that support ponding during 
winter and spring months (PCE 3).
    The physical and biological features essential to the conservation 
of the species in this subunit may require special management 
considerations or protection to address threats from nonnative plant 
species and anthropogenic activities (e.g., OHV use; unauthorized 
recreational use; impacts from development, including water run-off; 
and fire management). Please see the Special Management Considerations 
or Protection section of this proposed rule for a discussion of the 
threats to Riverside fairy shrimp habitat and potential management 
considerations.
Subunit 5h: J11 E and J11 W, J12, J16-18 (Goat Mesa)
    Subunit 5h is located in the Otay Mesa region of southern San Diego 
County, California. This subunit is north and west of subunit 5b, 
bounded by the U.S.-Mexico International Border to the south, and 
dissected by Jeep Trail. Subunit 5h consists of 11 ac (4 ha) of 
federally owned (DHS lands), 83 ac (34 ha) of locally owned land, and 
161 ac (65 ha) of privately owned land. The locally owned land is held 
by the City of San Diego, and the privately owned land includes 
holdings by Pardee Homes. Subunit 5h was not specifically identified in 
the 1998 Recovery Plan (Appendix F), but is classified as necessary to 
stabilize and protect (conserve) existing populations of Riverside 
fairy shrimp within the ``J2, J5, J7, J11-21, J23-30 Otay Mesa'' 
heading in Appendix F (Service 1998a, p. F1). This subunit was occupied 
at the time of listing and is currently occupied.
    This subunit is considered essential for the recovery of Riverside 
fairy shrimp because it includes one or more pools essential to 
maintain habitat function, genetic diversity, and species viability 
(Service 1998a, p. 65). Further, it is essential because the basin 
contains appropriate depth and ponding duration, soils, elevation, and 
water chemistry (pH, temperature, salinity, etc.), which fulfill 
Riverside fairy shrimp's life-history needs. Subunit 5h contains the 
physical and biological features that are essential to the conservation 
of Riverside fairy shrimp, including ephemeral wetland habitat (PCE 1), 
intermixed wetland and upland habitats that act as the local watershed 
(PCE 2), and the topography and soils that support ponding during 
winter and spring months (PCE 3).
    The physical and biological features essential to the conservation 
of the species in this subunit may require special management 
considerations or protection to address threats from nonnative plant 
species and anthropogenic activities (e.g., OHV use; unauthorized 
recreational use; impacts from development, including water run-off; 
and fire management). Please see the Special Management Considerations 
or Protection section of this proposed rule for a discussion of the 
threats to Riverside fairy shrimp habitat and potential management 
considerations.

[[Page 31719]]

Effects of Critical Habitat Designation

Section 7 Consultation

    Section 7(a)(2) of the Act requires Federal agencies, including the 
Service, to ensure that any action they fund, authorize, or carry out 
is not likely to jeopardize the continued existence of any endangered 
species or threatened species or result in the destruction or adverse 
modification of designated critical habitat of such species. In 
addition, section 7(a)(4) of the Act requires Federal agencies to 
confer with the Service on any agency action which is likely to 
jeopardize the continued existence of any species proposed to be listed 
under the Act or result in the destruction or adverse modification of 
proposed critical habitat.
    Decisions by the 5th and 9th Circuit Courts of Appeals have 
invalidated our regulatory definition of ``destruction or adverse 
modification'' (50 CFR 402.02) (see Gifford Pinchot Task Force v. U.S. 
Fish and Wildlife Service, 378 F. 3d 1059 (9th Cir. 2004) and Sierra 
Club v. U.S. Fish and Wildlife Service et al., 245 F.3d 434, 442 (5th 
Cir. 2001)), and we do not rely on this regulatory definition when 
analyzing whether an action is likely to destroy or adversely modify 
critical habitat. Under the statutory provisions of the Act, we 
determine destruction or adverse modification on the basis of whether, 
with implementation of the proposed Federal action, the affected 
critical habitat would continue to serve its intended conservation role 
for the species.
    If a Federal action may affect a listed species or its critical 
habitat, the responsible Federal agency (action agency) must enter into 
consultation with us. Examples of actions that are subject to the 
section 7 consultation process are actions on State, tribal, local, or 
private lands that require a Federal permit (such as a permit from the 
U.S. Army Corps of Engineers under section 404 of the Clean Water Act 
(33 U.S.C. 1251 et seq.) or a permit from the Service under section 10 
of the Act) or that involve some other Federal action (such as funding 
from the Federal Highway Administration, Federal Aviation 
Administration, or the Federal Emergency Management Agency). Federal 
actions not affecting listed species or critical habitat, and actions 
on State, tribal, local, or private lands that are not federally funded 
or authorized, do not require section 7 consultation.
    As a result of section 7 consultation, we document compliance with 
the requirements of section 7(a)(2) through our issuance of:
    (1) A concurrence letter for Federal actions that may affect, but 
are not likely to adversely affect, listed species or critical habitat; 
or
    (2) A biological opinion for Federal actions that may affect, or 
are likely to adversely affect, listed species or critical habitat.
    When we issue a biological opinion concluding that a project is 
likely to jeopardize the continued existence of a listed species and/or 
destroy or adversely modify critical habitat, we provide reasonable and 
prudent alternatives to the project, if any are identifiable, that 
would avoid the likelihood of jeopardy and/or destruction or adverse 
modification of critical habitat. We define ``reasonable and prudent 
alternatives'' (at 50 CFR 402.02) as alternative actions identified 
during consultation that:
    (1) Can be implemented in a manner consistent with the intended 
purpose of the action,
    (2) Can be implemented consistent with the scope of the Federal 
agency's legal authority and jurisdiction,
    (3) Are economically and technologically feasible, and
    (4) Would, in the Director's opinion, avoid the likelihood of 
jeopardizing the continued existence of the listed species, or avoid 
the likelihood of destroying or adversely modifying critical habitat, 
or both.
    Reasonable and prudent alternatives can vary from slight project 
modifications to extensive redesign or relocation of the project. Costs 
associated with implementing a reasonable and prudent alternative are 
similarly variable.
    Regulations at 50 CFR 402.16 require Federal agencies to reinitiate 
consultation on previously reviewed actions in instances where we have 
listed a new species or subsequently designated critical habitat that 
may be affected and the Federal agency has retained discretionary 
involvement or control over the action (or the agency's discretionary 
involvement or control is authorized by law). Consequently, Federal 
agencies sometimes may need to request reinitiation of consultation 
with us on actions for which formal consultation has been completed, if 
those actions with discretionary involvement or control may affect 
subsequently listed species or designated critical habitat.

Application of the ``Adverse Modification'' Standard

    The key factor related to the adverse modification determination is 
whether, with implementation of the proposed Federal action, the 
affected critical habitat would continue to serve its intended 
conservation role for the species. Activities that may destroy or 
adversely modify critical habitat are those that alter the physical and 
biological features to an extent that appreciably reduces the 
conservation value of critical habitat for Riverside fairy shrimp. As 
discussed above, the role of critical habitat is to support life-
history needs of the species and provide for the conservation of the 
species. For Riverside fairy shrimp, this includes supporting viable 
vernal pools containing the species and the associated microwatersheds 
upon which the pools depend.
    Section 4(b)(8) of the Act requires us to briefly evaluate and 
describe, in any proposed or final regulation that designates critical 
habitat, activities involving a Federal action that may destroy or 
adversely modify such habitat, or that may be affected by such 
designation.
    Activities that may affect Riverside fairy shrimp critical habitat, 
when carried out, funded, or authorized by a Federal agency, will 
require section 7 consultation. These activities include, but are not 
limited to:
    (1) Actions that result in ground disturbance. Such activities 
could include, but are not limited to, residential or commercial 
development, OHV activity, pipeline construction, new road construction 
or widening, existing road maintenance, manure dumping, and grazing. 
These activities potentially impact the habitat and physical and 
biological features essential to Riverside fairy shrimp by damaging, 
disturbing, and altering soil composition through direct impacts, 
increased erosion, and increased nutrient content. Additionally, 
changes in soil composition may lead to changes in the vegetation 
composition, thereby changing the overall habitat type.
    (2) Actions that would impact the ability of an ephemeral wetland 
to continue to provide habitat for Riverside fairy shrimp and other 
native species that require this specialized habitat type. Such 
activities could include, but are not limited to, water impoundment, 
stream channelization, water diversion, water withdrawal, and 
development activities. These activities could alter the biological and 
physical features essential to the conservation of Riverside fairy 
shrimp by eliminating ponding habitat; changing the duration and 
frequency of the ponding events on which this species relies; making 
the habitat too wet, thus allowing obligate wetland species to become 
established; making the habitat too dry, thus allowing upland species 
to become

[[Page 31720]]

established; causing large amounts of sediment or manure to be 
deposited in Riverside fairy shrimp habitat; or causing increased 
erosion and incising of waterways.
    (3) Actions that result in alteration of the hydrological regimes 
typically associated with Riverside fairy shrimp habitat, including 
actions that would impact the soil and topography that cause water to 
pond during the winter and spring months. Such activities could 
include, but are not limited to, deep-ripping of soils, trenching, soil 
compaction, and development activities. These activities could alter 
the biological and physical features essential to the conservation of 
Riverside fairy shrimp by eliminating ponding habitat, impacting the 
impervious nature of the soil layer, or making the soil so impervious 
that water pools for an extended period that is detrimental to 
Riverside fairy shrimp (see Primary Constituent Elements for Riverside 
Fairy Shrimp section above). These activities could alter surface 
layers and the hydrological regime in a manner that promotes loss of 
soil matrix components, ponding regimes, or hydrological connectivity 
to upland habitats to support the growth and reproduction of Riverside 
fairy shrimp.
    (4) Road construction and maintenance, right-of-way designation, 
and regulation of agricultural activities, or any activity funded or 
carried out by a Federal agency that could result in excavation or 
mechanized land clearing of Riverside fairy shrimp critical habitat. 
These activities could alter the habitat in such a way that cysts of 
Riverside fairy shrimp are crushed, Riverside fairy shrimp are removed, 
or ephemeral wetland habitat is permanently altered.

Exemptions

Application of Section 4(a)(3) of the Act

    The Sikes Act Improvement Act of 1997 (Sikes Act) (16 U.S.C. 670a) 
required each military installation that includes land and water 
suitable for the conservation and management of natural resources to 
complete an integrated natural resources management plan (INRMP) by 
November 17, 2001. An INRMP integrates implementation of the military 
mission of the installation with stewardship of the natural resources 
found on the base. Each INRMP includes:
    (1) An assessment of the ecological needs on the installation, 
including the need to provide for the conservation of listed species;
    (2) A statement of goals and priorities;
    (3) A detailed description of management actions to be implemented 
to provide for these ecological needs; and
    (4) A monitoring and adaptive management plan.
    Among other things, each INRMP must, to the extent appropriate and 
applicable, provide for fish and wildlife management; fish and wildlife 
habitat enhancement or modification; wetland protection, enhancement, 
and restoration where necessary to support fish and wildlife; and 
enforcement of applicable natural resource laws.
    The National Defense Authorization Act for Fiscal Year 2004 (Pub. 
L. 108-136) amended the Act to limit areas eligible for designation as 
critical habitat. Specifically, section 4(a)(3)(B)(i) of the Act (16 
U.S.C. 1533(a)(3)(B)(i)) now provides: ``The Secretary shall not 
designate as critical habitat any lands or other geographical areas 
owned or controlled by the Department of Defense, or designated for its 
use, that are subject to an integrated natural resources management 
plan prepared under section 101 of the Sikes Act (16 U.S.C. 670a), if 
the Secretary determines in writing that such plan provides a benefit 
to the species for which critical habitat is proposed for 
designation.''
    We consult with the military on the development and implementation 
of INRMPs for installations with federally listed species. We analyzed 
INRMPs developed by military installations located within the range of 
the proposed revised critical habitat designation for Riverside fairy 
shrimp to determine if they are exempt under section 4(a)(3) of the 
Act. The following areas are Department of Defense lands with 
completed, Service-approved INRMPs within the proposed revised critical 
habitat designation.

Approved INRMPs

MCB Camp Pendleton (Units 4 and portion of 2h)

    In the previous final critical habitat designation for Riverside 
fairy shrimp, we exempted MCB Camp Pendleton from the designation (70 
FR 19154; April 12, 2005). MCB Camp Pendleton completed their INRMP in 
November 2001, and updated the INRMP in March 2007 (U.S. Marine Corps 
2007). The INRMP includes the following conservation measures for the 
Riverside fairy shrimp: (1) Surveys and monitoring, studies, impact 
avoidance and minimization, and habitat restoration and enhancement; 
(2) species survey information stored in MCB Camp Pendleton's GIS 
database and recorded in a resource atlas which is published and 
updated on a semi-annual basis; (3) application of a 984-ft (300-m) 
radius to protect the micro-watershed buffers around current and 
historic Riverside fairy shrimp locations; and (4) use of the resource 
atlas to plan operations and projects to avoid impacts to the Riverside 
fairy shrimp and to trigger section 7 consultations if an action may 
affect the species. These measures are established, ongoing aspects of 
existing programs and/or Base directives (e.g., Range and Training 
Regulations), or measures that are being implemented as a result of 
previous consultations.
    MCB Camp Pendleton implements Base directives to avoid and minimize 
adverse effects to the Riverside fairy shrimp, such as: (1) Bivouac, 
command post, and field support activities should be no closer than 984 
ft (300 m) to occupied Riverside fairy shrimp habitat year round; (2) 
Vehicle and equipment operations should be limited to existing road and 
trail networks year round; and (3) Environmental clearance is required 
prior to any soil excavation, filling, or grading. MCB Camp Pendleton 
has also demonstrated ongoing funding of their INRMP and management of 
endangered and threatened species. MCB Camp Pendleton continues to 
expend significant resources for management of federally listed species 
and habitat on their land, including management actions that provide a 
benefit for the Riverside fairy shrimp. Moreover, in partnership with 
the Service, MCB Camp Pendleton provides funding for Service biologists 
to assist in implementing their Sikes Act program and buffer land 
acquisition initiative.
    Based on MCB Camp Pendleton's past funding history for listed 
species and their Sikes Act program (including the management of 
Riverside fairy shrimp), we believe there is a high degree of certainty 
that MCB Camp Pendleton will continue to implement the INRMP in 
coordination with the California Department of Fish and Game and with 
the Service in a manner that provides a benefit to the Riverside fairy 
shrimp. We also believe that there is a high degree of certainty that 
the conservation efforts of their INRMP will be effective. Service 
biologists work closely with MCB Camp Pendleton on a variety of 
endangered and threatened species issues, including the Riverside fairy 
shrimp. The management programs and Base directives to avoid and 
minimize impacts to the species are consistent with current and ongoing 
section 7 consultations with MCB Camp Pendleton.
    Lands that contain the features essential to the conservation of

[[Page 31721]]

Riverside fairy shrimp are within the following areas: San Onofre State 
Beach, State Park-leased land (near the Christianitos Creek foothills 
(portion of Subunit 2h); see paragraph below for discussion), Oscar 
One, Oscar Two, Victor, area south of Onofre State Park (Uniform 
Training Area), Red Beach, and Tango (U.S. Marine Corps 2007, Section 
4, pp. 51-76).
    State Park-leased lands are treated under the Real Estate 
Agreements and Lease section in the INRMP. Base real estate agreements 
(e.g., leases, easements, outleases, and assignments) cover 
approximately 5,000 ac of the Base (not inclusive of leased acreage 
within cantonment areas). These agreements include easements for public 
utilities and transit corridors; leases to public educational and 
retail agencies; State Beach leases; and agricultural leases for row 
crop production and seed collection.
    In the portion of Subunit 2h within MCB Camp Pendleton boundaries, 
permissible activities include military thoroughfares (use of roads), 
military training (with advanced coordination), fire suppression 
activities, and public recreational access. Lessees are required to 
manage the natural resources on the lands leased for their use 
consistent with the philosophies and supportive of the objectives of 
the Camp Pendleton INRMP. Each lessee that manages and/or controls use 
of lands leased from Camp Pendleton (e.g., State Parks, agriculture 
leases) is required to generate and submit a natural resources 
management plan for their leased lands for approval by the Base within 
one year of establishment of their lease or renewal. Lessees are also 
required to identify any activity that may affect federally regulated 
resources (e.g., listed species, wetlands, waters of the United States) 
and provide information and mitigation that may be required to support 
consultation with the applicable regulatory agency.
    Based on the above considerations, and in accordance with section 
4(a)(3)(B)(i) of the Act, we have determined that all identified lands 
are subject to the MCB Camp Pendleton INRMP and that conservation 
efforts identified in the INRMP will provide a benefit to Riverside 
fairy shrimp and vernal pool habitat on MCB Camp Pendleton. Therefore, 
lands within this installation are exempt from critical habitat 
designation under section 4(a)(3) of the Act. We are not including 
approximately 1,929 ac (781 ha) of habitat in this proposed revised 
critical habitat designation because of this exemption.

MCAS Miramar (Within Unit 4)

    In the previous final critical habitat designation for Riverside 
fairy shrimp, we exempted MCAS Miramar from the designation of critical 
habitat (70 FR 19154; April 12, 2005). MCAS Miramar completed an INRMP 
in May 2000, which was updated in October 2006 (Gene Stout and 
Associates et al. 2006). The INRMP is being implemented at MCAS 
Miramar. The INRMP provides for conservation, management, and 
protection of the Riverside fairy shrimp. The INRMP classifies nearly 
all of the vernal pool basins and watersheds on MCAS Miramar as a Level 
I Management Area. A Level I Management Area receives the highest 
conservation priority within the INRMP. Preventing damage to vernal 
pool resources is the highest conservation priority in management areas 
with the Level I designation. The conservation of vernal pool basins 
and watersheds in a Level I Management Area is achieved through 
educating base personnel; taking proactive measures to avoid accidental 
impacts, including signs and fencing; developing procedures to respond 
to and fix accidental impacts on vernal pools; and maintaining an 
updated inventory of vernal pool basins and associated vernal pool 
watersheds.
    Since the completion of MCAS Miramar's INRMP, the Service has 
received reports on their vernal pool monitoring and restoration 
program and correspondence detailing the installation's expenditures on 
the objectives outlined in its INRMP. MCAS Miramar continues to monitor 
and manage its vernal pool resources. Ongoing programs include a study 
on the effects of fire management on vernal pool resources, vernal pool 
mapping, and species/vernal pool surveys. Based on the value MCAS 
Miramar's INRMP assigns to vernal pool basins and watersheds, and the 
management actions undertaken to conserve them, we find that the INRMP 
provides a benefit for the Riverside fairy shrimp.
    Land that contains the features essential to the conservation of 
Riverside fairy shrimp is within the following area at MCAS Miramar: 
AA1 east complex, near the junction of Interstate 15 and Pomerado Road. 
Based on the aforementioned considerations, and in accordance with 
section 4(a)(3)(B)(i) of the Act, we have determined that conservation 
efforts identified in the INRMP provide a benefit to Riverside fairy 
shrimp and vernal pool habitat on 59 ac (24 ha) of habitat on the 
western portion of MCAS Miramar (Gene Stout and Associates et al. 2006, 
Section 7, pp. 17-23).
    Based on the above considerations, and in accordance with section 
4(a)(3)(B)(i) of the Act, we have determined that the identified lands 
are subject to the MCAS Miramar INRMP and that conservation efforts 
identified in the INRMP will provide a benefit to Riverside fairy 
shrimp occurring in habitats within or adjacent to MCAS Miramar. 
Therefore, lands within this installation are exempt from critical 
habitat designation under section 4(a)(3) of the Act. We are not 
including approximately 59 ac (24 ha) of habitat in this revised 
proposed critical habitat designation because of this exemption.

Exclusions

Application of Section 4(b)(2) of the Act

    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. The 
Secretary may exclude an area from critical habitat if he determines 
that the benefits of such exclusion outweigh the benefits of specifying 
such area as part of the critical habitat, unless he determines, based 
on the best scientific data available, that the failure to designate 
such area as critical habitat will result in the extinction of the 
species. In making that determination, the legislative history is clear 
that the Secretary has broad discretion regarding which factor(s) to 
use and how much weight to give to any factor.
    Under section 4(b)(2) of the Act, we may exclude an area from 
designated critical habitat based on economic impacts, impacts on 
national security, or any other relevant impacts. In considering 
whether to exercise our delegated discretion on behalf of the Secretary 
to exclude a particular area from the designation, we identify the 
benefits of including the area in the designation, identify the 
benefits of excluding the area from the designation, and evaluate 
whether the benefits of exclusion outweigh the benefits of inclusion. 
If the analysis indicates that the benefits of exclusion outweigh the 
benefits of inclusion, we may exercise our delegated discretion to 
exclude the area only if such exclusion would not result in the 
extinction of the species.
    When considering the benefits of inclusion for an area, we consider 
the additional regulatory benefits that area would receive from the 
protection from adverse modification or destruction as a result of 
actions with a Federal nexus, the educational benefits of mapping

[[Page 31722]]

essential habitat for recovery of the listed species, and any benefits 
that may result from a designation due to State or Federal laws that 
may apply to critical habitat.
    In the case of Riverside fairy shrimp, the benefits of critical 
habitat include public awareness of Riverside fairy shrimp presence and 
the importance of habitat protection, and in cases where a Federal 
nexus exists, increased habitat protection for Riverside fairy shrimp 
due to the protection from adverse modification or destruction of 
critical habitat. In practice, a Federal nexus exists only on Federal 
land or for projects undertaken, funded, or requiring authorization by 
a Federal agency.
    When identifying the benefits of exclusion, we consider, among 
other things, whether exclusion of a specific area is likely to benefit 
national security; ameliorate disparate economic impacts; result in 
conservation; result in the continuation, strengthening, or 
encouragement of partnerships; or results in implementation of a 
management plan that provides equal to or more conservation than a 
critical habitat designation would provide. When we evaluate the 
existence of a conservation plan when considering the benefits of 
exclusion, we consider a variety of factors, including but not limited 
to, whether the plan is finalized, how it provides for the conservation 
of the essential physical and biological features, whether there is a 
reasonable expectation that the conservation management strategies and 
actions contained in a management plan will be implemented into the 
future, whether the conservation strategies in the plan are likely to 
be effective, and whether the plan contains a monitoring program or 
adaptive management to ensure that the conservation measures are 
effective and can be adapted in the future in response to new 
information.
    After identifying the benefits of inclusion and the benefits of 
exclusion, we carefully weigh the two sides to determine whether the 
benefits of exclusion outweigh those of inclusion. If we determine that 
they do, we then determine whether exclusion would result in 
extinction. If exclusion of an area from critical habitat will result 
in extinction, we will not exclude it from the designation.
    Based on the information from our economic analysis, provided by 
entities seeking exclusion, as well as any additional public comments 
we receive, we will evaluate whether certain lands in the proposed 
revised critical habitat are appropriate for exclusion from the final 
designation pursuant to section 4(b)(2) of the Act. If we conclude that 
the benefits of excluding lands from the final designation outweigh the 
benefits of designating those lands as critical habitat, then we may 
exercise our delegated discretion to exclude the lands from the final 
designation.
    We are considering exercising our delegated discretion to exclude 
the following lands from the critical habitat designation for Riverside 
fairy shrimp: Subunits 2c; 2i; portions of Subunits 2dA, 2dB, and 2e; 
2f; 2g; all of Unit 3 (Subunits 3c, 3d, 3e, 3f, 3g, and 3h); Unit 4; 
and a portion of Subunit 5d.
    We are considering whether to exclude these areas because:
    (1) Their value for conservation will be preserved for the 
foreseeable future by existing protective actions, or
    (2) They are appropriate for exclusion under the ``other relevant 
factor'' provisions of section 4(b)(2) of the Act.
    However, we specifically solicit comments on the inclusion or 
exclusion of these areas. In the paragraphs below, we provide a 
detailed analysis of our proposed exclusion of these lands under 
section 4(b)(2) of the Act.

 Table 5--Areas Being Considered for Exclusion From the Riverside Fairy
  Shrimp Proposed Revised Critical Habitat Under Section 4(b)(2) of the
                                   Act
------------------------------------------------------------------------
                 Subunit by plan**                         Acreage
------------------------------------------------------------------------
                   Orange County Central-Coastal NCCP
------------------------------------------------------------------------
2c. (MCAS) El Toro.................................      26 ac (11 ha)
2i. SCE Viejo Conservation Bank....................      63 ac (25 ha)
                                                    --------------------
    Subtotal for Orange County Central-Coastal           89 ac (36 ha)
     Subregional NCCP/HCP..........................
------------------------------------------------------------------------
                  Orange County Southern Subregion HCP
------------------------------------------------------------------------
2dA. Saddleback Meadows............................       4 ac (2 ha)
2dB. O'Neill Regional Park--near Trabuco Canyon....      75 ac (30 ha)
2e. O'Neill Regional Park--near Ca[ntilde]ada            47 ac (19 ha)
 Gobernadora/east of Tijeras Creek.................
2f. Chiquita Ridge.................................      56 ac (23 ha)
2g. Radio Tower Road...............................      51 ac (21 ha)
                                                    --------------------
    Subtotal for Orange County Southern Subregion       233 ac (94 ha)
     HCP...........................................
------------------------------------------------------------------------
                     Western Riverside County MSHCP
------------------------------------------------------------------------
3c. Australia Pool.................................      19 ac (8 ha)
3d. Scott Road Pool................................       9 ac (4 ha)
3e. Schleuniger Pool...............................      23 ac (9 ha)
3f. Skunk Hollow and Field Pool (Barry Jones            163 ac (66 ha)
 Wetland Mitigation Bank)..........................
3g. Johnson Ranch Created Pools....................      54 ac (22 ha)
3h. Santa Rosa Plateau--Mesa de Colorado...........     597 ac (242 ha)
                                                    --------------------
    Subtotal for Western Riverside County MSHCP....     865 ac (350 ha)
------------------------------------------------------------------------
                      San Diego MHCP--Carlsbad HMP
------------------------------------------------------------------------
4c. Poinsettia Lane Commuter Train Station (JJ2)...       9 ac (4 ha)
    Subtotal Carlsbad HMP under the San Diego MHCP.       9 ac (4 ha)
------------------------------------------------------------------------

[[Page 31723]]

 
            County of San Diego Subarea Plan under the MSCP
------------------------------------------------------------------------
5d. J29-31 (portion)...............................      23 ac (9 ha)
                                                    --------------------
    Subtotal County of San Diego Subarea Plan under      23 ac (9 ha)
     the MSCP......................................
====================================================--------------------
        Total......................................   1,219 ac (493 ha)* 
------------------------------------------------------------------------
* Values in this table may not sum due to rounding.
** All lands that fall within the boundaries of an HCP are being
  considered for exclusion, with the exception of the City of San Diego
  Subarea Plan. Because the Riverside fairy shrimp is no longer a
  covered species under the City of San Diego's Subarea Plan under the
  MSCP (City relinquished their permit on April 20, 2010), we are not
  considering for exclusion critical habitat areas falling within the
  boundary of the City of San Diego Subarea Plan.

Exclusions Based on Economic Impacts
    Under section 4(b)(2) of the Act, we consider the economic impacts 
of specifying any particular area as critical habitat. In order to 
consider economic impacts, we are preparing a new analysis of the 
economic impacts of the proposed revised critical habitat designation 
and related factors.
    We prepared and finalized an analysis of the economic impacts for 
the previous proposed critical habitat designation (Economic and 
Planning Systems, Inc. 2005). That economic analysis determined that 
retrospective costs (costs since listing, 1993-2004) total $400 
million. Total prospective costs of the 2004 proposed rule were $70 to 
$370 million in impacts that may occur in the 20 years (2004-2024) 
following the proposed designation of critical habitat. Based on the 
2004 economic analysis, we concluded that the designation of critical 
habitat for Riverside fairy shrimp, as proposed in 2004, would not 
result in significant small business impacts. This analysis is 
presented in the notice of availability for the economic analysis 
published in the Federal Register on October 19, 2004 (69 FR 61461).
    The prior economic analysis included costs coextensive with the 
listing of the species, in other words, costs attributable to the 
listing of the species as well as costs attributable to the designation 
of critical habitat. Because the Act directs the Secretary to consider 
the economic impacts of specifying any particular area as critical 
habitat, we believe the appropriate framework for analysis is to 
compare the costs associated with actions in a world with critical 
habitat to those costs likely to be incurred in the absence of critical 
habitat designation. Our new analysis will therefore focus on the 
specific costs attributable to designating the areas proposed in this 
proposed rule as critical habitat.
    We will announce the availability of the draft economic analysis as 
soon as it is completed, at which time we will seek public review and 
comment. At that time, copies of the draft economic analysis will be 
available for downloading from the Internet at http://www.regulations.gov, or by contacting the Carlsbad Fish and Wildlife 
Office directly (see FOR FURTHER INFORMATION CONTACT section). During 
the development of a final designation, we will consider economic 
impacts, public comments, and other new information, and areas may be 
excluded from the final critical habitat designation under section 
4(b)(2) of the Act and our implementing regulations at 50 CFR 424.19.
Exclusions Based on National Security Impacts
    Under section 4(b)(2) of the Act, we may exclude an area from 
designated critical habitat for reasons of national security. We 
consider whether there are lands owned or managed by the DOD or 
Department of Homeland Security (DHS) where a national security impact 
might exist. In preparing this proposal, we have exempted from the 
designation of critical habitat those Department of Defense lands with 
completed INRMPs determined to provide a benefit to Riverside fairy 
shrimp but where a national security impact may exist. Areas identified 
as owned and managed by DOD on MCB Camp Pendleton and MCAS Miramar that 
are exempt from critical habitat designation under section 4(a)(3) of 
the Act are discussed in the Exemptions section above. We are not 
proposing any lands for exclusions based on national security impacts 
under section 4(b)(2) of the Act in this proposed revised critical 
habitat.
Exclusions Based on Other Relevant Impacts
    Under section 4(b)(2) of the Act, we consider any other relevant 
impacts, in addition to economic impacts and impacts on national 
security. We take into account a number of factors including whether 
there are habitat conservation plans (HCPs) or other management plans 
covering an area, or whether there are conservation partnerships that 
would be encouraged by designation of, or exclusion from, critical 
habitat. In addition, we look at any Tribal issues, and consider the 
government-to-government relationship of the United States with Tribal 
entities. We also consider any social impacts that might occur because 
of the designation.
Land and Resource Management Plans, Conservation Plans, or Agreements 
Based on Conservation Partnerships
    We are considering the exclusion of current land management or 
conservation plans (HCPs as well as other types) that include measures 
to protect and manage Riverside fairy shrimp and its habitat.
    We are considering the exclusion of non-Federal lands covered by 
the Orange County Central-Coastal NCCP/HCP, the Orange County Southern 
Subregion HCP, the Western Riverside County MSHCP, City of Carlsbad HMP 
under the San Diego MHCP, and County of San Diego Subarea Plan under 
the MSCP that provide measures to protect Riverside fairy shrimp and 
its habitat (see Table 5 above for a list of areas we are considering 
for exclusion). Portions of the proposed revised critical habitat units 
for Riverside fairy shrimp may warrant exclusion from the designation 
of critical habitat under section 4(b)(2) of the Act based on the 
partnerships, management, and protection afforded under these approved 
and legally operative HCPs that are redundant with, and thus reduce the 
benefits provided by critical habitat designation. Only lands that fall 
within HCP boundaries are being considered for exclusion. All lands 
that fall within the boundaries of an HCP are being considered for

[[Page 31724]]

exclusion, with the exception of the City of San Diego Subarea Plan. 
Because the Riverside fairy shrimp is no longer a covered species under 
the City of San Diego's Subarea Plan under the MSCP (City relinquished 
their permit on April 20, 2010; see below), we are not considering 
excluding critical habitat areas falling within the boundary of the 
City of San Diego Subarea Plan. In this proposed rule, we are seeking 
input from the HCP stakeholders and the public as to reasons supporting 
whether or not we should exercise our delegated discretion to exclude 
these areas from the final critical habitat designation. We are 
requesting comments on the benefit to Riverside fairy shrimp from these 
plans (see Public Comments section).
    We are not considering the exclusion of non-federal lands covered 
by the City of San Diego Subarea Plan under the MSCP. Based on a 2006 
Federal district court ruling in Center for Biological Diversity v. 
Bartel, 98-CV-2234 (S.D.Cal.), the court enjoined the incidental take 
permit issued to the City of San Diego based on the City's Subarea 
Plan, as it applied to Riverside fairy shrimp and six other vernal pool 
species. The court held that the City's Subarea Plan does not provide 
adequate protection for Riverside fairy shrimp as a result of Plan 
deficiencies and in light of Solid Waste Agency of Northern Cook County 
(SWANCC) v. U.S. Army Corps of Engineers, 531 U.S. 159 (2001). As a 
result, the City surrendered permit coverage for seven vernal pool 
species, including Riverside fairy shrimp on April 20, 2010, and the 
Service cancelled the permit insofar as it applied to the seven species 
on May 14, 2010. Because the Riverside fairy shrimp is no longer a 
covered species under the City of San Diego's Subarea Plan under the 
MSCP, we are not considering for exclusion critical habitat areas 
falling within the boundary of the City of San Diego Subarea Plan. The 
City is currently preparing a new HCP to obtain incidental take 
coverage for the Riverside fairy shrimp and other vernal pool species. 
Despite the City's relinquishment of their permit, 54 percent, or 1,369 
pools of all currently identified vernal pool habitat within the 
boundaries of the City's subarea plan have been conserved by covenant 
of easement, conservation easement, or dedication in fee title to the 
City (City of San Diego 1997, 2006). The City continues to monitor and 
manage vernal pools in support of the MSCP.
Orange County Central-Coastal NCCP
    The Orange County Central-Coastal NCCP/HCP was developed in 
cooperation with numerous local jurisdictions, State agencies and 
participating landowners, including the cities of Anaheim, Costa Mesa, 
Irvine, Orange, and San Juan Capistrano; Southern California Edison; 
Transportation Corridor Agencies; The Irvine Company; California 
Department of Parks and Recreation; Metropolitan Water District of 
Southern California; and the County of Orange. Approved in 1996, the 
Central-Coastal NCCP/HCP provides for the establishment of 
approximately 38,738 ac (15,677 ha) of reserve land for 39 Federal or 
State-listed and unlisted sensitive species within the 208,713 ac 
(84,463 ha) plan area in central and coastal Orange County. The Orange 
County Central-Coastal NCCP/HCP is a multi-species conservation program 
that minimizes and mitigates expected habitat loss and associated 
incidental take of covered species within the plan area. The ``Reserve 
System'' created pursuant to the NCCP/HCP is designed to function 
effectively as a multiple-habitat and multiple-species reserve that 
specifically includes vernal pool habitat and Riverside fairy shrimp 
(R.J. Meade Consulting, Inc. 1996).
    The Orange County Central--Coastal NCCP/HCP provides for monitoring 
and adaptive management of covered species and their habitat within 
this Reserve System (Consultation 1-6-FW-24, Service 1996, pp. 
1-4). Conditionally covered species, including the Riverside fairy 
shrimp, receive protection not only through the establishment and 
management of the Reserve System, but also additional mitigation 
measures specified in the NCCP/HCP and Implementing Agreement (IA) 
(Service 1996, p. 6). Under the NCCP/HCP, incidental take for Riverside 
fairy shrimp is limited to highly degraded or artificial vernal pools. 
Take of Riverside fairy shrimp in non-degraded, natural vernal pool 
habitat is not authorized. If a planned activity will affect Riverside 
fairy shrimp in a highly degraded or artificial vernal pool, it ``must 
be consistent with a mitigation plan that: 1) Addresses design 
modifications and other on-site measures that are consistent with the 
project's purposes, minimizes impacts, and provides appropriate 
protections for vernal pool habitat, 2) provides for compensatory 
vernal pool habitat restoration/creation at an appropriate location 
(which may include the reserve or other open space) and includes 
relocation of potential cyst-bearing soils, and 3) provides for 
monitoring and adaptive management of vernal pools consistent with 
Chapter 5 of this NCCP'' (R.J. Meade Consulting, Inc. 1996; p. 97).
    Permittees implement the above conservation measures for Riverside 
fairy shrimp and other covered species over the 75-year permit term, as 
well as provide commitments in perpetuity regarding habitat protection 
for lands in the Reserve System and commitments outlined in the IA 
(R.J. Meade Consulting 1996, p. 12). The Service acknowledged in the IA 
that the Orange County Central-Coastal NCCP/HCP provides for the 
conservation, protection, restoration, enhancement, and management of 
the species covered under the plan (including Riverside fairy shrimp) 
and their habitats.
    To date, monitoring and management related to Riverside fairy 
shrimp have included reserve-wide vernal pool surveys conducted from 
1997 through 2001 and ongoing control of invasive nonnative vegetation 
in the upland environment. We are considering exercising our delegated 
discretion to exclude a total of 89 ac (36 ha) of land that are owned 
by or are under the jurisdiction of the permittees of the Orange County 
Central-Coastal NCCP/HCP (see Table 5 above).
Orange County Southern Subregion HCP
    A large-scale HCP encompassing approximately 86,021 ac (34,811 ha) 
in southern Orange County, the Orange County Southern Subregion HCP is 
a multi-species conservation program that minimizes and mitigates 
expected habitat loss and associated incidental take of covered 
species. The Southern Subregion HCP was developed in support of 
applications for incidental take permits for 32 covered species, 
including Riverside fairy shrimp, by the County of Orange (County), 
Rancho Mission Viejo, LLC (Rancho Mission Viejo), and the Santa 
Margarita Water District (Water District) in connection with proposed 
residential development and related actions in southern Orange County. 
The Service issued permits based on the plan on January 10, 2007. The 
permit and plan cover a 75 year period.
    The Southern Subregion HCP provides for the conservation of covered 
species, including Riverside shrimp, through the establishment of an 
approximately 30,426 ac (12,313 ha) habitat reserve and 4,456 ac (1,803 
ha) of supplemental open space areas (Service 2007, p. 19), which 
primarily consists of land owned by Rancho Mission Viejo and three pre-
existing County parks (Service 2007, pp. 10, 19). Subunits 2g and 2h 
fall within the boundaries of the habitat reserve of this HCP.

[[Page 31725]]

    The Southern Subregion HCP is expected to provide benefits for the 
conservation of Riverside fairy shrimp through the implementation of 
the following conservation measures: conservation of vernal pools 
within the habitat reserve; minimizing impacts to vernal pools from 
development; maintaining water quality/quantity; controlling non-native 
invasive species; managing livestock grazing; and minimizing human 
access and disturbance. Specifically, any development must be located 
at least 1000 ft. (305 m) away from the vernal pools and be built at a 
lower elevation than the vernal pools to avoid hydrological alterations 
(Service 2007, p. 133). Water quality monitoring will be conducted 
throughout the life of the permit at occupied vernal pools near 
development (Service 2007, p. 133).
    We acknowledged in the Implementing Agreement for the Orange County 
Southern Subregion HCP that the conservation strategy for this HCP 
provides a comprehensive, habitat-based approach to the protection of 
covered species and their habitats by focusing on the lands and aquatic 
resource areas essential for the long-term conservation of the covered 
species (including Riverside fairy shrimp) and by providing for 
appropriate management for those lands (Dudek 2007, p. 64). This 
acknowledgement was made for habitat within Subarea 1, which includes 
all of the habitat reserve lands, including Subunits 2g and 2h of the 
proposed critical habitat.
    The Orange County Southern Subregion HCP currently provides 
conservation for the Riverside fairy shrimp habitat at O'Neill Regional 
Park, Chiquita Ridge, and Radio Tower Road, all within Unit 2, most of 
which is within the boundaries of the HCP. Unit 2g consists of 51 ac 
(21 ha), all of which is private land within the HCP. Unit 2f consists 
of 56 ac (23 ha) that is also private land within the HCP. Portions of 
Subunits 2dA (4 ac (2 ha)), 2dB (75 ac (30 ha)), and 2e (47 ac (19 ha)) 
also fall within the boundaries of the HCP. The land is conserved with 
conservation easements, and funds were designated for the management of 
this area to benefit vernal pool species, including Riverside fairy 
shrimp (Service 2007, pp. 15-17). We are considering exercising our 
delegated discretion to exclude a total of 233 ac (94 ha) of land that 
falls within the jurisdiction of the Orange County Southern Subregion 
HCP (see Table 5 above). We intend to exclude critical habitat from 
areas covered by the Orange County Southern Subregion HCP based on the 
protections outlined above and per the provisions laid out in the IA, 
to the extent consistent with the requirements of 4(b)(2) of the Act. 
We encourage any public comment in relation to our consideration of the 
areas in portions of Subunits 2dA, 2dB, 2e, and subunits 2g and 2h for 
inclusion or exclusion (see Public Comments section above).
Western Riverside County Multiple Species Habitat Conservation Plan 
(Western Riverside County MSHCP)
    The Western Riverside County MSHCP is a regional, multi-
jurisdictional HCP encompassing approximately 1.26 million ac (510,000 
ha) of land in western Riverside County. The Western Riverside County 
MSHCP addresses 146 listed and unlisted ``covered species,'' including 
Riverside fairy shrimp. The Western Riverside County MSHCP is a 
multispecies conservation program designed to minimize and mitigate the 
expected loss of habitat and associated incidental take of covered 
species resulting from covered development activities in the plan area. 
On June 22, 2004, the Service issued a single incidental take permit 
under section 10(a)(1)(B) of the Act to 22 permittees under the Western 
Riverside County MSHCP to be in effect for a period of 75 years 
(Service 2004). Core areas for Riverside fairy shrimp at Skunk Hollow 
and Field Pool (Barry Jones Wetland Mitigation Bank), Lake Elsinore 
Back Basin (Australia pool), and Murrieta (Schleuniger pool) will be 
conserved or will remain within the MSHCP Conservation Area. The Plan 
provides for the survival of the species within the Plan Area by 
ensuring the species is conserved within 90 percent of occupied areas 
with long-term conservation value, and will support recovery by 
enhancing habitat conserved for the species.
    The Western Riverside County MSHCP, when fully implemented, will 
establish approximately 153,000 ac (61,917 ha) of new conservation 
lands (Additional Reserve Lands) to complement the approximate 347,000 
ac (140,426 ha) of preexisting natural and open space areas (Public/
Quasi-Public (PQP) lands) in the plan area. PQP lands include those 
under ownership of public agencies, primarily the U.S. Forest Service 
(USFS) and Bureau of Land Management (BLM), as well as permittee-owned 
or controlled open-space areas managed by the State of California and 
Riverside County. Collectively, the Additional Reserve Lands and PQP 
lands form the overall Western Riverside County MSHCP Conservation 
Area. The configuration of the 153,000 ac (61,916 ha) of Additional 
Reserve Lands (ARL) is not mapped or precisely delineated (``hard-
lined'') in the Western Riverside County MSHCP. Instead, the 
configuration and composition of the ARL are described in text within 
the bounds of the approximately 310,000-ac (125,453-ha) criteria area. 
ARL lands are being acquired and conserved as part of the ongoing 
implementation of the Western Riverside County MSHCP.
    Species-specific conservation objectives are included in the 
Western Riverside County MSHCP for Riverside fairy shrimp. One 
objective is to conserve at least 11,942 ac (4,833 ha) of occupied or 
suitable habitat for the species. In addition, other areas within the 
Criteria Area identified as important for the Riverside fairy shrimp 
will be conserved. This objective is intended to be met through 
implementation of the Protection of Species Associated with Riparian/
Riverine Areas and Vernal Pools policy under the Plan, which states 
that for occupied properties, 90 percent of the area that provides 
long-term conservation value for Riverside fairy shrimp shall be 
conserved. We acknowledged in section 14.10 of the Implementing 
Agreement (IA) for the Western Riverside County MSHCP that the plan 
provides a comprehensive, habitat-based approach to the protection of 
covered species, including Riverside fairy shrimp, by focusing on lands 
essential for the long-term conservation of the covered species and 
appropriate management for those lands (WRCRCA et al. 2003, p. 51).
    Consistent with the terms of the IA we are considering exercising 
our delegated discretion to exclude 865 ac (350 ha) of Riverside fairy 
shrimp habitat on permittee-owned or controlled land in Unit 3 that 
meets the definition of critical habitat for Riverside fairy shrimp 
within the Western Riverside County MSHCP under section 4(b)(2) of the 
Act. The 1993 final listing rule for Riverside fairy shrimp attributed 
the primary threat from present or threatened destruction, modification 
or curtailment of its habitat or to: urban and agricultural 
development, off-road vehicle use, cattle trampling, human trampling, 
road development, military activities, and water management activities 
(58 FR 41387; August 3, 1993). The 1993 final listing rule also 
identified other natural and manmade factors including introduction of 
nonnative plant species, competition with invading species, trash 
dumping, fire, fire suppression activities, and drought (58 FR 41389; 
August 3, 1993) as primary threats to Riverside fairy shrimp. The 
Western Riverside County MSHCP helps to address these threats through a 
regional planning effort, and

[[Page 31726]]

outlines species-specific objectives and criteria for the conservation 
of Riverside fairy shrimp. We intend to exclude critical habitat from 
areas covered by the Western Riverside County MSHCP based on the 
protections outlined above and per the provisions laid out in the IA, 
to the extent consistent with the requirements of 4(b)(2) of the Act. 
We encourage any public comment in relation to our consideration of the 
areas in Unit 3 for inclusion or exclusion (see Public Comments section 
above).
Multiple Habitat Conservation Program (MHCP), in San Diego County--
Carlsbad HMP
    The Multiple Habitat Conservation Program (MHCP) is a 
comprehensive, multi-jurisdictional, planning program designed to 
create, manage, and monitor an ecosystem preserve in northwestern San 
Diego County. The MHCP is also a subregional plan under the State of 
California's Natural Communities Conservation Plan (NCCP) program that 
was developed in cooperation with California Department of Fish and 
Game (CDFG). The MHCP preserve system (i.e., focused planning area or 
FPA) is intended to protect viable populations of native plant and 
animal species and their habitats in perpetuity, while accommodating 
continued economic development and quality of life for residents of 
northern San Diego County. The MHCP includes an approximately 112,000-
ac (45,324-ha) study area within the cities of Carlsbad, Encinitas, 
Escondido, San Marcos, Oceanside, Vista, and Solana Beach. These cities 
will implement their respective portions of the MHCP through subarea 
plans. Only the City of Carlsbad has completed its subarea plan at this 
time, which is called the Carlsbad Habitat Management Plan (Carlsbad 
HMP). The section 10(a)(1)(B) incidental take permit and Implementing 
Agreement for the City of Carlsbad HMP were issued on November 12, 2004 
(Service 2004c). Conservation requirements within the Carlsbad HMP for 
Riverside fairy shrimp include conserving 100 percent of the known 
Riverside fairy shrimp habitat and implementation of the MHCP's narrow 
endemic and no-net-loss of wetlands (including vernal pools) policies 
for any additional vernal pools discovered in MHCP planning area These 
policies require all vernal pools and their watersheds within the MHCP 
study area to be 100 percent conserved, regardless of occupancy by 
Riverside fairy shrimp and regardless of location inside or outside of 
the FPA, unless doing so would remove all economic uses of a property. 
In the event that no project alternative is feasible that avoids all 
impacts on a particular property, the impacts must be minimized and 
mitigated to achieve no net loss of biological functions and values 
(Service 2004, p. 330).
    Unit 4c covers the Poinsettia Commuter Train Station vernal pool 
complex within the Carlsbad HMP, and consists of 9 ac (4 ha); 3 ac (1 
ha) of private property and a 6-ac (2-ha) property owned by the North 
County Transit District. The Poinsettia Commuter Train Station vernal 
pool complex supports the only known occurrence of Riverside fairy 
shrimp within the boundaries of the Carlsbad HMP. The Riverside fairy 
shrimp is a conditionally-covered species under the Carlsbad HMP, and 
the City of Carlsbad will receive full coverage for this species when 
the Poinsettia Commuter Train Station vernal pool complex is managed, 
monitored and protected in perpetuity, as outlined in the biological 
opinion for the Carlsbad HMP (Service 2004, pp. 327-33). While funds 
have been designated through past consultations for managing and 
monitoring of these properties to benefit vernal pool species, 
including Riverside fairy shrimp, a long-term manager has not been 
identified and no one is currently managing or monitoring these 
properties. In addition, the properties are not protected with recorded 
conservation easements.
    We agreed in the Implementing Agreement (IA) for the Carlsbad HMP 
that we would consider the Carlsbad HMP in the preparation of any 
proposed critical habitat designation for a covered species, and 
further acknowledged that the Carlsbad HMP incorporates special 
management actions to manage covered species and their habitats in a 
manner that will provide for the conservation of the covered species, 
including Riverside fairy shrimp (City of Carlsbad et al. 2004, p. 17).
    We are considering exercising our delegated discretion to exclude 
under section 4(b)(2) of the Act a total of 9 ac (4 ha) that meet the 
definition of critical habitat for Riverside fairy shrimp within the 
Carlsbad HMP under the MHCP. We will analyze the benefits of inclusion 
and the benefits of exclusion of the area covered by this subarea plan 
in the final revised critical habitat rule for Riverside fairy shrimp. 
We encourage any public comment in relation to our consideration of the 
areas in Subunit 4c for exclusion (see Public Comments section above).
San Diego Multiple Species Conservation Program (MSCP)--County of San 
Diego Subarea Plan
    Riverside fairy shrimp is covered under the County of San Diego 
Subarea Plan. We are considering exercising our delegated discretion to 
exclude lands covered by this plan (see Table 5 for a list of the areas 
that we are considering for exclusion). Portions of the proposed 
revised critical habitat units for Riverside fairy shrimp may warrant 
exclusion from the designation of critical habitat under section 
4(b)(2) of the Act based on the partnerships, management, and 
protection afforded under this approved and legally operative HCP that 
are redundant with protections provided by critical habitat 
designation. Only lands that fall within HCP boundaries are being 
considered for exclusion. In this proposed rule, we are seeking input 
from the HCP stakeholders and the public as to reasons supporting 
whether or not we should exclude these areas from the final critical 
habitat designation.
    The Multiple Species Conservation Program (MSCP) is a comprehensive 
habitat conservation planning program that encompasses 582,243 ac 
(235,626 ha) within 12 jurisdictions of southwestern San Diego County. 
The MSCP is a subregional plan that identifies the conservation needs 
of 85 federally listed and sensitive species, including the Riverside 
fairy shrimp, and serves as the basis for development of subarea plans 
by each jurisdiction in support of section 10(a)(1)(B) permits. The 
subregional MSCP identifies where mitigation activities should be 
focused, such that upon full implementation of the subarea plans 
approximately 171,920 ac (69,574 ha) of the 582,243-ac (235,626-ha) 
MSCP plan area will be preserved and managed for covered species. The 
MSCP also provides for a regional biological monitoring program, and 
Riverside fairy shrimp is identified as a first priority species for 
field monitoring.
    Consistent with the MSCP, the conservation of Riverside fairy 
shrimp is addressed in the County of San Diego Subarea Plan. The County 
of San Diego Subarea Plan identifies areas that are hard-lined for 
conservation and areas where mitigation activities should be focused to 
assemble its preserve (i.e., Pre-approved Mitigation Area). 
Implementation of the County of San Diego Subarea Plan will result in a 
minimum 98, 379-ac (39,813 ha) preserve area.
    Subunit 5d is within the County of San Diego Subarea Plan and is 
identified as a hard-lined preserve area.

[[Page 31727]]

These hard-lined preserve lands were designated in conjunction with the 
Otay Ranch Specific plan and are to be conveyed to a land manager 
(e.g., County or Federal government) in phases such that 1.18 ac (0.48 
ha) is conserved for every 1 ac (0.40 ha) developed. A natural resource 
management plan has been developed that addresses the preservation, 
enhancement, and management of sensitive natural resources on the 
22,899-ac (9,267ha) Otay Ranch hard-lined preserve area (MSCP 1997, pp. 
3-15).
    In Section 9.17 of the Implementing Agreement (IA) for the Subarea 
Plan we agreed to consider the MSCP and County of San Diego Subarea 
Plan in our preparation of any proposed critical habitat designations 
concerning any covered species, including Riverside fairy shrimp 
(Service et al. 1998, p. 23).
    We are considering exercising our delegated discretion to exclude 
from critical habitat a portion of subunit 5d covered by the County of 
San Diego Subarea Plan under section 4(b)(2) of the Act. This area 
encompasses approximately 23 ac (9 ha) of land.

Peer Review

    In accordance with our joint policy on peer review published in the 
Federal Register on July 1, 1994 (59 FR 34270), we will seek the expert 
opinions of at least three appropriate and independent specialists 
regarding this proposed rule. The purpose of peer review is to ensure 
that our critical habitat designation is based on scientifically sound 
data, assumptions, and analyses. We will invite these peer reviewers to 
comment during the public comment period on our specific assumptions 
and conclusions in this proposed revised designation of critical 
habitat.
    We will consider all comments and information we receive during the 
comment period on this proposed rule during our preparation of a final 
determination. Accordingly, the final decision may differ from this 
proposal.

Public Hearings

    Section 4(b)(5) of the Act provides for one or more public hearings 
on this proposal, if requested. Requests must be received within 45 
days after the date of this proposed rule in the Federal Register. Such 
requests must be sent to the address shown in the FOR FURTHER 
INFORMATION CONTACT section. We will schedule public hearings on this 
proposal, if any are requested, and announce the dates, times, and 
places of those hearings, as well as how to obtain reasonable 
accommodations, in the Federal Register and local newspapers at least 
15 days before the hearing.

Required Determinations

Regulatory Planning and Review--Executive Order 12866

    The Office of Management and Budget (OMB) has determined that this 
rule is not significant under Executive Order 12866 (Regulatory 
Planning and Review). OMB bases its determination upon the following 
four criteria:
    (1) Whether the rule will have an annual effect of $100 million or 
more on the economy or adversely affect an economic sector, 
productivity, jobs, the environment, or other units of the government.
    (2) Whether the rule will create inconsistencies with other Federal 
agencies' actions.
    (3) Whether the rule will materially affect entitlements, grants, 
user fees, loan programs, or the rights and obligations of their 
recipients.
    (4) Whether the rule raises novel legal or policy issues.

Regulatory Flexibility Act (5 U.S.C. 601 et seq.)

    Under the Regulatory Flexibility Act (RFA; 5 U.S.C. 601 et seq.), 
as amended by the Small Business Regulatory Enforcement Fairness Act 
(SBREFA) of 1996 (5 U.S.C. 801 et seq.), whenever an agency must 
publish a notice of rulemaking for any proposed or final rule, it must 
prepare and make available for public comment a regulatory flexibility 
analysis that describes the effect of the rule on small entities (small 
businesses, small organizations, and small government jurisdictions). 
However, no regulatory flexibility analysis is required if the head of 
an agency certifies the rule will not have a significant economic 
impact on a substantial number of small entities. SBREFA amended the 
RFA to require Federal agencies to provide a certification statement of 
factual basis for certifying that the rule will not have a significant 
economic impact on a substantial number of small entities.
    We are preparing a new analysis of the economic impacts of this 
proposed revision to critical habitat for Riverside fairy shrimp. At 
this time, we lack current economic information necessary to provide an 
updated factual basis for the required RFA finding with regard to this 
proposed revision to critical habitat. Therefore, we defer the RFA 
finding until completion of the draft economic analysis prepared under 
section 4(b)(2) of the Act and Executive Order 12866. Upon completion 
of the draft economic analysis, we will announce availability of the 
draft economic analysis of the proposed designation in the Federal 
Register and reopen the public comment period for the proposed 
designation. We will include with this announcement, as appropriate, an 
initial regulatory flexibility analysis or a certification that the 
rule will not have a significant economic impact on a substantial 
number of small entities accompanied by the factual basis for that 
determination. We have concluded that deferring the RFA finding until 
completion of the draft economic analysis is necessary to meet the 
purposes and requirements of the RFA. Deferring the RFA finding in this 
manner will ensure that we make a sufficiently informed determination 
based on adequate economic information and provide the necessary 
opportunity for public comment.

Energy Supply, Distribution, or Use--Executive Order 13211

    Executive Order 13211 (Actions Concerning Regulations That 
Significantly Affect Energy Supply, Distribution, or Use) requires 
agencies to prepare Statements of Energy Effects when undertaking 
certain actions. We do not expect the designation of this proposed 
critical habitat to significantly affect energy supplies, distribution, 
or use. Based on an analysis conducted for the previous designation of 
critical habitat and extrapolated to this designation, along with a 
further analysis of the additional areas included in this revision, we 
determined that this proposed rule to designate revised critical 
habitat for Riverside fairy shrimp is not expected to significantly 
affect energy supplies, distribution, or use. Therefore, this action is 
not a significant energy action, and no Statement of Energy Effects is 
required. However, we will further evaluate this issue as we conduct 
our economic analysis, and review and revise this assessment as 
warranted.

Unfunded Mandates Reform Act (2 U.S.C. 1501 et seq.)

    In accordance with the Unfunded Mandates Reform Act (2 U.S.C. 1501 
et seq.), we make the following findings:
    (1) This rule would not produce a Federal mandate. In general, a 
Federal mandate is a provision in legislation, statute, or regulation 
that would impose an enforceable duty upon State, local, or Tribal 
governments, or the private sector, and includes both ``Federal 
intergovernmental mandates'' and ``Federal private sector mandates.'' 
These terms are defined in 2 U.S.C. 658(5)-(7). ``Federal 
intergovernmental mandate'' includes a regulation that

[[Page 31728]]

``would impose an enforceable duty upon State, local, or tribal 
governments'' with two exceptions. It excludes ``a condition of Federal 
assistance.'' It also excludes ``a duty arising from participation in a 
voluntary Federal program,'' unless the regulation ``relates to a then-
existing Federal program under which $500,000,000 or more is provided 
annually to State, local, and tribal governments under entitlement 
authority,'' if the provision would ``increase the stringency of 
conditions of assistance'' or ``place caps upon, or otherwise decrease, 
the Federal Government's responsibility to provide funding,'' and the 
State, local, or Tribal governments ``lack authority'' to adjust 
accordingly. At the time of enactment, these entitlement programs were: 
Medicaid; Aid to Families with Dependent Children work programs; Child 
Nutrition; Food Stamps; Social Services Block Grants; Vocational 
Rehabilitation State Grants; Foster Care, Adoption Assistance, and 
Independent Living; Family Support Welfare Services; and Child Support 
Enforcement. ``Federal private sector mandate'' includes a regulation 
that ``would impose an enforceable duty upon the private sector, except 
(i) a condition of Federal assistance or (ii) a duty arising from 
participation in a voluntary Federal program.''
    The designation of critical habitat does not impose a legally 
binding duty on non-Federal Government entities or private parties. 
Under the Act, the only regulatory effect is that Federal agencies must 
ensure that their actions do not destroy or adversely modify critical 
habitat under section 7. While non-Federal entities that receive 
Federal funding, assistance, permits, or that otherwise require 
approval or authorization from a Federal agency for an action, may be 
indirectly impacted by the designation of critical habitat, the legally 
binding duty to avoid destruction or adverse modification of critical 
habitat rests squarely on the Federal agency. Furthermore, to the 
extent that non-Federal entities are indirectly impacted because they 
receive Federal assistance or participate in a voluntary Federal aid 
program, the Unfunded Mandates Reform Act would not apply, nor would 
critical habitat shift the costs of the large entitlement programs 
listed above onto State governments.
    (2) We do not expect this rule to significantly or uniquely affect 
small governments. Small governments would be affected only to the 
extent that any programs having Federal funds, permits, or other 
authorized activities must ensure that their actions would not 
adversely affect the critical habitat. Therefore, a Small Government 
Agency Plan is not required. However, as we conduct our economic 
analysis for the rule, we will further evaluate this issue and revise 
this assessment if appropriate.

Takings--Executive Order 12630

    In accordance with Executive Order 12630 (Government Actions and 
Interference with Constitutionally Protected Private Property Rights), 
we have analyzed the potential takings implications of designating 
critical habitat for Riverside fairy shrimp in a takings implications 
assessment. Critical habitat designation does not affect landowner 
actions that do not require Federal funding or permits, nor does it 
preclude development of habitat conservation programs or issuance of 
incidental take permits to permit actions that do require Federal 
funding or permits to go forward. The takings implications assessment 
concludes that this designation of revised critical habitat for 
Riverside fairy shrimp would not pose significant takings implications 
for lands within or affected by the designation.

Federalism--Executive Order 13132

    In accordance with Executive Order 13132 (Federalism), this 
proposed rule does not have significant Federalism effects. A 
Federalism assessment is not required. In keeping with Department of 
the Interior and Department of Commerce policy, we requested 
information from, and coordinated development of, this proposed 
critical habitat designation with appropriate State resource agencies 
in California. The designation of critical habitat in areas currently 
occupied by the Riverside fairy shrimp imposes no additional 
restrictions to those currently in place and, therefore, has little 
incremental impact on State and local governments and their activities. 
The designation may have some benefit to these governments because the 
areas that contain the physical and biological features essential to 
the conservation of the species are more clearly defined, and the 
elements of the features of the habitat essential to the conservation 
of the species are specifically identified. This information does not 
alter where and what federally sponsored activities may occur. However, 
it may assist local governments in long-range planning (rather than 
having them wait for case-by-case section 7 consultations to occur).
    Where State and local governments require approval or authorization 
from a Federal agency for actions that may affect critical habitat, 
consultation under section 7(a)(2) would be required. While non-Federal 
entities that receive Federal funding, assistance, or permits, or that 
otherwise require approval or authorization from a Federal agency for 
an action, may be indirectly impacted by the designation of critical 
habitat, the legally binding duty to avoid destruction or adverse 
modification of critical habitat rests squarely on the Federal agency.

Civil Justice Reform--Executive Order 12988

    In accordance with Executive Order 12988 (Civil Justice Reform), it 
has been determined that the rule does not unduly burden the judicial 
system and meets the requirements of sections 3(a) and 3(b)(2) of the 
Order. We have proposed to revise critical habitat in accordance with 
the provisions of the Act. This proposed rule uses standard property 
descriptions and identifies the elements of the physical and biological 
features essential to the conservation of Riverside fairy shrimp within 
the designated areas to assist the public in understanding the habitat 
needs of the species.

Paperwork Reduction Act of 1995 (44 U.S.C. 3501 et seq.)

    This rule does not contain any new collections of information that 
require approval by OMB under the Paperwork Reduction Act of 1995 (44 
U.S.C. 3501 et seq.). This rule will not impose recordkeeping or 
reporting requirements on State or local governments, individuals, 
businesses, or organizations. An agency may not conduct or sponsor, and 
a person is not required to respond to, a collection of information 
unless it displays a currently valid OMB control number.

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

    It is our position that, outside the jurisdiction of the U.S. Court 
of Appeals for the Tenth Circuit, we do not need to prepare 
environmental analyses pursuant to the National Environmental Policy 
Act (NEPA; 42 U.S.C. 4321 et seq.) in connection with designating 
critical habitat under the Act. We published a notice outlining our 
reasons for this determination in the Federal Register on October 25, 
1983 (48 FR 49244). This position was upheld by the U.S. Court of 
Appeals for the Ninth Circuit (Douglas County v. Babbitt, 48 F.3d 1495 
(9th Cir. 1995), cert. denied 516 U.S. 1042 (1996)).

[[Page 31729]]

Clarity of the Rule

    We are required by Executive Orders 12866 and 12988 and by the 
Presidential Memorandum of June 1, 1998, to write all rules in plain 
language. This means that each rule we publish must:
    (1) Be logically organized;
    (2) Use the active voice to address readers directly;
    (3) Use clear language rather than jargon;
    (4) Be divided into short sections and sentences; and
    (5) Use lists and tables wherever possible.
    If you feel that we have not met these requirements, send us 
comments by one of the methods listed in the ADDRESSES section. To 
better help us revise the rule, your comments should be as specific as 
possible. For example, you should tell us the numbers of the sections 
or paragraphs that are unclearly written, which sections or sentences 
are too long, the sections where you feel lists or tables would be 
useful, etc.

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 
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.
    We determined that there are no tribal lands that were occupied by 
Riverside fairy shrimp at the time of listing that contain the features 
essential to the conservation of the species, and no tribal lands 
unoccupied by Riverside fairy shrimp that are essential for the 
conservation of the species. Therefore, we are not proposing to 
designate critical habitat for Riverside fairy shrimp on tribal lands. 
We will continue to coordinate with tribal governments as applicable 
during the designation process.

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 
Field Supervisor, Carlsbad Fish and Wildlife Office (see FOR FURTHER 
INFORMATION CONTACT).

Authors

    The primary authors of this package are the staff members of the 
Carlsbad Fish and Wildlife Office.

List of Subjects in 50 CFR Part 17

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

Proposed Regulation Promulgation

    Accordingly, we propose to amend part 17, subchapter B of chapter 
I, title 50 of the Code of Federal Regulations, as set forth below:

PART 17--ENDANGERED AND THREATENED WILDLIFE AND PLANTS

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

    Authority:  16 U.S.C. 1361-1407; 16 U.S.C. 1531-1544; 16 U.S.C. 
4201-4245; Pub. L. 99-625, 100 Stat. 3500; unless otherwise noted.

    2. In Sec.  17.95, amend paragraph (h) by revising the entry for 
``Riverside Fairy Shrimp (Streptocephalus woottoni)'' to read as 
follows:


Sec.  17.95  Critical habitat--fish and wildlife.

* * * * *
    (h) Crustaceans.
* * * * *
Riverside Fairy Shrimp (Streptocephalus woottoni)
    (1) Unit descriptions are depicted for Ventura, Orange, Riverside, 
and San Diego Counties, California, on the maps below.
    (2) Within these areas, the primary constituent elements of the 
physical and biological features essential to the conservation of 
Riverside fairy shrimp consist of three components:
    (i) Ephemeral wetland habitat consisting of vernal pools and 
ephemeral habitat that have wet and dry periods appropriate for the 
incubation, maturation, and reproduction of Riverside fairy shrimp in 
all but the driest of years, such that the pools:
    (A) Are inundated (pond) approximately 2 to 8 months during winter 
and spring, typically filled by rain, surface and subsurface flow;
    (B) Generally dry down in the late spring to summer months;
    (C) May not pond every year; and
    (D) Provide the suitable water chemistry characteristics to support 
Riverside fairy shrimp. These characteristics include physiochemical 
factors such as alkalinity, pH, temperature, dissolved solutes, 
dissolved oxygen, which can vary depending on the amount of recent 
precipitation, evaporation, or oxygen saturation; time of day; season; 
and type and depth of soil and subsurface layers. Vernal pool habitat 
typically exhibits a range of conditions but remains within the 
physiological tolerance of the species. The general ranges of 
conditions include but are not limited to:
    (1) Dilute, freshwater pools with low levels of total dissolved 
solids (low ion levels (sodium ion concentrations generally below 70 
mmol/l);
    (2) Low alkalinity levels (lower than 80 to 1,000 milligrams per 
liter (mg/l)), and
    (3) A range of pH levels from neutral to alkaline (typically in 
range of 6.4-7.1).
    (ii) Intermixed wetland and upland habitats that function as the 
local watershed, including topographic features characterized by 
mounds, swales, and low-lying depressions within a matrix of upland 
habitat that result in intermittently flowing surface and subsurface 
water in swales, drainages, and pools described in paragraph (h)(2(i) 
of this entry. Associated watersheds provide water to fill the vernal 
or ephemeral pools in the winter and spring months. Associated 
watersheds vary in size and therefore cannot be generalized, and they 
are affected by factors including surface and underground hydrology, 
the topography of the area surrounding the pool or pools, the 
vegetative coverage, and the soil substrates in the area. Size of 
associated watershed likely varies from a few acres to greater than 100 
ac (40 ha).
    (iii) Soils that support ponding during winter and spring which are 
found in areas characterized in paragraphs (h)(2)(i) and (h)(2)(ii), 
respectively, of this entry, that have a clay component or other 
property that creates an impermeable surface or subsurface layer. Soil 
series with a clay component or an impermeable surface or subsurface 
layer typically slow percolation, increase water run-off (at least 
initially), and contribute to the filling and persistence of ponding of 
ephemeral wetland habitat where Riverside fairy shrimp occur. Soils and 
soil series known to support vernal pool habitat include, but are not 
limited to:
    (A) The Azule, Calleguas, Cropley, and Linne soils series in 
Ventura County;
    (B) The Alo, Balcom, Bosanko, Calleguas, Cieneba, and Myford soils 
series in Orange County;
    (C) The Cajalco, Claypit, Murrieta, Porterville, Ramona, Traver, 
and

[[Page 31730]]

Willows soils series in Riverside County; and
    (D) The Diablo, Huerhuero, Linne, Placentia, Olivenhain, Redding, 
Salinas, and Stockpen soils series in San Diego County.
    (3) Critical habitat does not include manmade structures (such as 
buildings, aqueducts, runways, roads, and other paved areas) and the 
land on which they are located existing within the legal boundaries on 
the effective date of this rule.
    (4) Critical habitat map units. Data layers defining map units were 
created using a base of U.S. Geological Survey 7.5' quadrangle maps. 
Unit descriptions were then mapped using Universal Transverse Mercator 
(UTM) zone 11, North American Datum (NAD) 1983 coordinates.
    (5) Note: Index map of critical habitat units for the Riverside 
fairy shrimp (Streptocephalus woottoni) follows:
BILLING CODE 4310-55-P
[GRAPHIC] [TIFF OMITTED] TP01JN11.000


[[Page 31731]]


    (6) Unit 1: Ventura County, California.
    (i) Subunit 1a: Tierra Rejada Preserve. [Reserved for textual 
description of subunit.]
    (ii) Subunit 1b: South of Tierra Rejada Valley. [Reserved for 
textual description of subunit.]
    (iii) Map of Unit 1, subunits 1a and 1b, follows:
    [GRAPHIC] [TIFF OMITTED] TP01JN11.001
    
    (7) Unit 2: Los Angeles Basin-Orange County Foothills--Orange 
County, California.
    (i) Subunit 2c: (MCAS) El Toro.
    (A) [Reserved for textual description of subunit.]
    (B) Map of Subunit 2c, (MCAS) El Toro, follows:

[[Page 31732]]

[GRAPHIC] [TIFF OMITTED] TP01JN11.002

    (ii) Subunit 2dA: Saddleback Meadows.
    (A) [Reserved for textual description of subunit.]
    (B) Map of Subunit 2dA, Saddleback Meadows, and subunit 2dB, 
O'Neill Regional Park--near Trabuco Canyon, follows:

[[Page 31733]]

[GRAPHIC] [TIFF OMITTED] TP01JN11.003

    (iii) Subunit 2dB: O'Neill Regional park--near Trabuco Canyon.
    (A) [Reserved for textual description of subunit.]
    (B) Map of Subunit 2dB, O'Neill Regional Park--near Trabuco Canyon, 
is provided at paragraph (h)(7)(ii)(b) of this entry.
    (iv) Subunit 2e: O'Neill Regional Park--near Ca[ntilde]ada 
Gobernadora.
    (A) [Reserved for textual description of subunit.]
    (B) Map of Subunit 2e, O'Neill Regional Park--near Ca[ntilde]ada 
Gobernadora, follows:

[[Page 31734]]

[GRAPHIC] [TIFF OMITTED] TP01JN11.004

    (v) Subunit 2f: Chiquita Ridge.
    (A) [Reserved for textual description of subunit.]
    (B) Note: Map of Subunit 2f, Chiquita Ridge, follows:

[[Page 31735]]

[GRAPHIC] [TIFF OMITTED] TP01JN11.005

    (vi) Subunit 2g: Radio Tower Road.
    (A) [Reserved for textual description of subunit.]
    (B) Map of Subunit 2g, Radio Tower Road, follows:

[[Page 31736]]

[GRAPHIC] [TIFF OMITTED] TP01JN11.006

    (vii) Subunit 2h: San Onofre State Beach, State Park-leased land 
(near Christianitos Creek foothills).
    (A) [Reserved for textual description of subunit.]
    (B) Map of Subunit 2h, San Onofre State Beach, State Park-leased 
land (near Christianitos Creek foothills)- near Camp Pendleton, 
follows:

[[Page 31737]]

[GRAPHIC] [TIFF OMITTED] TP01JN11.007

BILLING CODE 4310-55-C
    (viii) Subunit 2i: SCE Viejo Conservation Bank.
    (A) [Reserved for textual description of subunit.]
    (B) Map of Subunit 2i, SCE Viejo Conservation Bank, follows:
BILLING CODE 4310-55-P

[[Page 31738]]

[GRAPHIC] [TIFF OMITTED] TP01JN11.008

    (8) Unit 3: Riverside Inland Valleys--Riverside County, California.
    (i) Subunit 3c: Australia Pool.
    (A) [Reserved for textual description of subunit.]
    (B) Map of Subunit 3c, Australia Pool, follows:

[[Page 31739]]

[GRAPHIC] [TIFF OMITTED] TP01JN11.009

    (ii) Subunit 3d: Scott Road Pool.
    (A) [Reserved for textual description of subunit.]
    (B) Map of Subunit 3d, Scott Road Pool, follows:

[[Page 31740]]

[GRAPHIC] [TIFF OMITTED] TP01JN11.010

    (iii) Subunit 3e: Schleuniger Pool.
    (A) [Reserved for textual description of subunit.]
    (B) Map of Subunit 3e, Schleuniger Pool, follows:

[[Page 31741]]

[GRAPHIC] [TIFF OMITTED] TP01JN11.011

    (iv) Subunit 3f: Skunk Hollow and Field Pool (Barry Jones Wetland 
Mitigation Bank).
    (A) [Reserved for textual description subunit.]
    (B) Map of Subunit 3f, Skunk Hollow and Field Pool, and Subunit 3g, 
Johnson Ranch Created Pools follows:
BILLING CODE 4310-55-C

[[Page 31742]]

[GRAPHIC] [TIFF OMITTED] TP01JN11.012

    (v) Subunit 3g: Johnson Ranch Created Pools.
    (A) [Reserved for textual description of subunit.]
    (B) Map of Subunit 3g, Johnson Ranch Created Pools, is provided at 
paragraph (h)(8)(iv)(B) of this entry.
    (vi) Subunit 3h: Santa Rosa Plateau--Mesa de Colorado.
    (A) [Reserved for textual description of subunit.]
    (B) Map of Subunit 3h, Santa Rosa Plateau--Mesa de Colorado, 
follows:

[[Page 31743]]

[GRAPHIC] [TIFF OMITTED] TP01JN11.013

    (9) Unit 4: San Diego North and Central Coastal Mesas--San Diego 
County, California.
    (i) Poinsettia Lane Commuter Train Station (JJ2). [Reserved for 
textual description of unit.]
    (ii) Map of Unit 4, Poinsettia Lane Commuter Train Station--JJ2, 
follows:

[[Page 31744]]

[GRAPHIC] [TIFF OMITTED] TP01JN11.014

    (10) Unit 5: San Diego Southern Coastal Mesas--San Diego County, 
California. (i) Subunit 5a: Sweetwater (J33).
    (A) [Reserved for textual description of subunit.]
    (B) Map of Subunits 5a, 5b, 5e, 5f, 5g, and 5h follows:

[[Page 31745]]

[GRAPHIC] [TIFF OMITTED] TP01JN11.015

    (ii) Subunit 5b: Arnie's Point (J15).
    (A) [Reserved for textual description of subunit.]
    (B) Map of Subunit 5b, Arnie's Point--J15, is provided at paragraph 
(h)(10)(i)(B) of this entry.
    (iii) Subunit 5c: East Otay Mesa.
    (A) [Reserved for textual description of subunit.]
    (B) Map of Subunit 5c, East Otay Mesa, follows:

[[Page 31746]]

[GRAPHIC] [TIFF OMITTED] TP01JN11.016

    (iv) Subunit 5d: J29-31.
    (A) [Reserved for textual description of subunit.]
    (B) Map of Subunit 5d, J29-31, follows:

[[Page 31747]]

[GRAPHIC] [TIFF OMITTED] TP01JN11.017

    (v) Subunit 5e: J2 N, J4, J5 (Robinhood Ridge).
    (A) [Reserved for textual description of subunit.]
    (B) Map of Subunit 5e, J2 N, J4, J5 (Robinhood Ridge), is provided 
at paragraph (h)(10)(i)(B) of this entry.
    (vi) Subunit 5f: J2 W and J2 S (Hidden Trails, Cal Terraces, and 
Otay Mesa Road).
    (A) [Reserved for textual description of subunit.]
    (B) Map of Subunit 5f, J 2W, and J 2S--Hidden Trails, Cal Terraces, 
and Otay Mesa Road, is provided at paragraph (h)(10)(i)(B) of this 
entry.
    (vii) Subunit 5g: J14.
    (A) [Reserved for textual description of subunit.]
    (B) Map of Subunit 5g, J14, is provided at paragraph (h)(10)(i)(B) 
of this entry.
    (viii) Subunit 5h: (J11 E, J11 W, J12, J16-18 (Goat Mesa)).
    (A) [Reserved for textual description of subunit.]
    (B) Map of Subunit 5h, J11 E, J11 W, J12, J16-18 (Goat Mesa), is 
provided at paragraph (h)(10)(i)(B) of this entry.
* * * * *

    Dated: May 19, 2011.
Eileen Sobeck,
Acting Assistant Secretary for Fish Wildlife and Parks.
[FR Doc. 2011-12947 Filed 5-31-11; 8:45 am]
BILLING CODE 4310-55-C