[Federal Register Volume 76, Number 45 (Tuesday, March 8, 2011)]
[Proposed Rules]
[Pages 12683-12690]
From the Federal Register Online via the Government Printing Office [www.gpo.gov]
[FR Doc No: 2011-5177]
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DEPARTMENT OF THE INTERIOR
Fish and Wildlife Service
50 CFR Part 17
[Docket No. FWS-R2-ES-2011-0011; MO 92210-0-0008]
Endangered and Threatened Wildlife and Plants; 90-Day Finding on
a Petition To List the Texas Kangaroo Rat as Endangered or Threatened
AGENCY: Fish and Wildlife Service, Interior.
ACTION: Notice of petition finding and initiation of status review.
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SUMMARY: We, the U.S. Fish and Wildlife Service (Service), announce a
90-day finding on a petition to list the Texas kangaroo rat, Dipodomys
elator, as endangered or threatened and to designate critical habitat
under the Endangered Species Act of 1973, as amended. Based on our
review, we find that the petition presents substantial scientific or
commercial information indicating that listing the Texas kangaroo rat
may be warranted. Therefore, with the publication of this notice, we
are initiating a status review to determine if listing the Texas
kangaroo rat is warranted. To ensure the status review is
comprehensive, we are requesting scientific and commercial data and
other information regarding this species. Based on the status review,
we will issue a 12-month finding on the petition, which will address
whether the petitioned action is warranted, as provided in section
4(b)(3)(B) of the Act.
DATES: To allow us adequate time to conduct this review, we request
that we receive information on or before May 9, 2011. Please note that
if you are using the Federal eRulemaking Portal (see ADDRESSES section,
below), the deadline for submitting an electronic comment is 11:59 p.m.
Eastern Time on this date. After May 9, 2011, you must submit
information directly to the Arlington Ecological Services Field Office
(see FOR FURTHER INFORMATION CONTACT section below). Please note that
we might not be able to address or incorporate information that we
receive after the above requested date.
ADDRESSES: You may submit information by one of the following methods:
Federal eRulemaking Portal: http://www.regulations.gov. In
the box that reads ``Enter Keyword or ID,'' enter the Docket number for
this finding, which is FWS-R2-ES-2011-0011. Check the box that reads
``Open for Comment/Submission,'' and then click the Search button. You
should then see an icon that reads ``Submit a Comment.'' Please ensure
that you have found the correct rulemaking before submitting your
comment.
U.S. mail or hand-delivery: Public Comments Processing,
Attn: FWS-R2-ES-2011-0011; Division of Policy and Directives
Management; U.S. Fish and Wildlife Service; 4401 N. Fairfax Drive,
Suite 222; Arlington, VA 22203.
We will post all information received on http://www.regulations.gov.
This generally means that we will post any personal information you
provide us (see the Request for Information section below for more
details).
FOR FURTHER INFORMATION CONTACT: Thomas J. Cloud, Jr., Field
Supervisor, Arlington Ecological Services Field Office, 711 Stadium
Drive, Suite 252, Arlington, TX 76011; by telephone (817) 277-1100; or
by facsimile (817) 277-1129. If you use a telecommunications device for
the deaf (TDD), please call the Federal Information Relay Service
(FIRS) at 800-877-8339.
SUPPLEMENTARY INFORMATION:
Request for Information
When we make a finding that a petition presents substantial
information indicating that listing a species may be warranted, we are
required to promptly review the status of the species (status review).
For the status review to be complete and based on the best available
scientific and commercial information, we request information on the
Texas kangaroo rat from governmental agencies, Native American Tribes,
the scientific community, industry, and any other interested parties.
We seek information on:
(1) The species' biology, range, and population trends, including:
(a) Habitat requirements for feeding, breeding, and sheltering;
(b) Genetics and taxonomy;
(c) Historical and current range, including distribution patterns;
(d) Historical and current population levels, and current and
projected trends; and
(e) Past and ongoing conservation measures for the species, its
habitat, or both.
(2) The factors that are the basis for making a listing
determination for a
[[Page 12684]]
species under section 4(a) of the Endangered Species Act of 1973, as
amended (Act) (16 U.S.C. 1531 et seq.), which are:
(a) The present or threatened destruction, modification, or
curtailment of its habitat or range;
(b) Overutilization for commercial, recreational, scientific, or
educational purposes;
(c) Disease or predation;
(d) The inadequacy of existing regulatory mechanisms; or
(e) Other natural or manmade factors affecting its continued
existence.
(3) Current land use or recent trends in north-central Texas as
they pertain to both cultivated crop and cattle ranching.
If, after the status review, we determine that listing the Texas
kangaroo rat is warranted, we will propose critical habitat (see
definition in section 3(5)(A) of the Act) under section 4 of the Act,
to the maximum extent prudent and determinable at the time we propose
to list the species. Therefore, within the geographical range currently
occupied by the Texas kangaroo rat, we request data and information on:
(1) What may constitute ``physical or biological features essential
to the conservation of the species;''
(2) Where such physical or biological features are currently found;
and
(3) Whether any of these features may require special management
considerations or protection.
In addition, we request data and information on ``specific areas
outside the geographical area occupied by the species'' that are
``essential to the conservation of the species.'' Please provide
specific comments and information as to what, if any, critical habitat
you think we should propose for designation if the species is proposed
for listing, and explain why such habitat meets the requirements of
section 4 of the Act.
Please include sufficient information with your submission (such as
scientific journal articles or other publications) to allow us to
verify any scientific or commercial information you include.
Submissions merely stating support for or opposition to the action
under consideration without providing supporting information, although
noted, will not be considered in making a determination. Section
4(b)(1)(A) of the Act directs that determinations as to whether any
species is an endangered or threatened species must be made ``solely on
the basis of the best scientific and commercial data available.''
You may submit your information concerning this status review by
one of the methods listed in the ADDRESSES section. If you submit
information via http://www.regulations.gov, your entire submission--
including any personal identifying information--will be posted on the
Web site. If you submit a hardcopy that includes personal identifying
information, you may request at the top of your document that we
withhold this personal identifying information from public review.
However, we cannot guarantee that we will be able to do so. We will
post all hardcopy submissions on http://www.regulations.gov.
Information and supporting documentation that we received and used
in preparing this finding will be available for you to review at http://www.regulations.gov, or you may make an appointment during normal
business hours at the U.S. Fish and Wildlife Service, Arlington
Ecological Services Field Office (see FOR FURTHER INFORMATION CONTACT).
Background
Section 4(b)(3)(A) of the Act (16 U.S.C. 1533(b)(3)(A)) requires
that we make a finding on whether a petition to list, delist, or
reclassify a species presents substantial scientific or commercial
information indicating that the petitioned action may be warranted. We
are to base this finding on information submitted with the petition,
supporting information submitted with the petition, and information
otherwise available in our files at the time we make the finding. The
following five documents represent information contained within our
files and are cited in this document: Jones and Bogan (1986), Martin
(2002), Shaw (1990), Stangl and Schafer (1990), and Wahl (1987). All
other cited references were supplied as part of the petition. To the
maximum extent practicable, we are to make this finding within 90 days
of our receipt of the petition and publish our notice of the finding
promptly in the Federal Register.
Our standard for substantial scientific or commercial information
within the Code of Federal Regulations (CFR) with regard to a 90-day
finding is ``that amount of information that would lead a reasonable
person to believe that the measure proposed in the petition may be
warranted'' (50 CFR 424.14(b)). If we find that substantial scientific
or commercial information was presented, we are required to promptly
conduct a species status review, which is subsequently summarized in
our 12-month finding.
Petition History
On January 15, 2010, we received a petition dated January 11, 2010,
from WildEarth Guardians of Denver, Colorado, requesting the Texas
kangaroo rat be listed as endangered or threatened and that critical
habitat be designated under the Act. The petition clearly identified
itself as such and included the requisite identification information
for the petitioner, as required by 50 CFR 424.14(a). In a July 19,
2010, letter to the petitioner, we responded that we reviewed the
information presented in the petition and determined that issuing an
emergency regulation temporarily listing the species under section
4(b)(7) of the Act was not warranted. We also stated that due to court
orders and judicially approved settlement agreements for other listing
and critical habitat determinations under the Act that required nearly
all of our listing and critical habitat funding for fiscal year 2010,
we would not be able to further address the petition at that time but
would complete the action when workload and funding allowed. This
finding addresses the petition.
Previous Federal Actions
The Texas kangaroo rat was previously listed as a category 2
candidate species under the Act on December 30, 1982 (47 FR 58454).
Category 2 candidates were taxa for which information in our possession
indicated that proposing to list was possibly appropriate, but for
which substantial data on biological vulnerability and threats were not
available to support a proposed listing rule. On December 5, 1996, we
published a notice of decision that discontinued the practice of
maintaining a category 2 candidate list (61 FR 64481).
Species Information
The Texas kangaroo rat (Dipodomys elator), also referred to as
Loring's kangaroo rat (Davis 1942, pp. 328-329), was first described by
Merriam in 1894 (pp. 109-110). Merriam (1894, pp. 109-110) originally
stated D. elator was similar to the banner-tailed kangaroo rat (D.
spectabilis) based on general external morphology (body structure) and
Phillip's kangaroo rat (D. phillipsii) based on its cranial arch (curve
of the skull). Dalquest and Collier (1964, p. 148) suggested D. elator
most resembles D. ornatus (no common name) with regard to its habits,
appearance, and skull. Best and Schnell (1974, p. 266) also indicated
the Texas kangaroo rat most resembled D. ornatus based on bacular
(penis bone) measurements. Measurements taken from the baculum, a bone
found in the penis of some mammals, varies in shape and size by species
and its characteristics are
[[Page 12685]]
sometimes used to differentiate between similar species. More recent
studies have suggested the Texas kangaroo rat is closely associated
with Phillip's kangaroo rat, although these studies did not include D.
ornatus in their methodology (Hamilton et al. 1987, p. 777; Mantooth et
al. 2000, p. 888). Even though the phylogenetic relationship (genetic
relationship of a group of organisms) between Dipodomys species is not
currently resolved, we accept the characterization of the Texas
kangaroo rat as a species because this status is generally accepted in
the scientific community (Mantooth et al. 2000, p. 885).
The Texas kangaroo rat has an average total length of approximately
290 millimeters (mm) (11.4 inches (in)) (Merriam 1894, p. 109), and has
large hind feet as is typical of members of this genus. It has a
brownish-yellow dorsum (upper surface) and is whitish along its ventral
(belly) surface. The Texas kangaroo rat also has a white-tipped tail
and four toes on its hind feet, distinguishing it from Ord's kangaroo
rat (D. ordii), which has five toes on its hind feet and whose range
overlaps that of the Texas kangaroo rat (Caire et al. 1989, p. 204).
Generally, Texas kangaroo rats inhabit arid areas that are not
prone to flooding (Martin 2002, p. 34); are characterized by short,
sparse grasses (Dalquest and Collier 1964, p. 147; Goetze et al. 2007,
p. 18; Nelson et al. 2009, p. 126); and contain little woody canopy
cover (Goetze et al. 2007, p. 18). Texas kangaroo rats prefer areas
where the soil contains a sufficient clay component to support their
burrows (Bailey 1905, p. 149; Dalquest and Collier 1964, p. 148;
Roberts and Packard 1973, p. 958; Martin and Matocha 1991, p. 355;
Goetze et al. 2007, p. 17), although it is not exclusively restricted
to such soils (Martin and Matocha 1991, p. 355). Their burrows are
often associated with Prosopis spp. (mesquite trees) (Dalquest and
Collier 1964, p. 147; Martin and Matocha 1972, p. 875), although
subsequent research has suggested this association may be
circumstantial (Stangl et al. 1992b, p. 31; Goetze et al. 2007, p. 20;
Nelson et al. 2009, p. 128). For dust bathing, Texas kangaroo rats
require areas of bare ground that may not be available in patches of
dense vegetation (Goetze et al. 2008, pp. 312-313; Nelson et al. 2009,
p. 127). As such, the Texas kangaroo rat appears to opportunistically
burrow in minimally disturbed areas (Stangl et al. 1992b, pp. 25-35;
Goetze et al. 2007, p. 19; Nelson et al. 2009, pp. 128-129).
Texas kangaroo rats primarily feed on grass seeds (Chapman 1972,
pp. 878-879). However, the seeds, leaves, fruits, and flowers of annual
forbs may also be a significant portion of their diet (Chapman 1972,
pp. 878-879). Although they do not tend to construct their burrows in
croplands (Martin and Matocha 1972, p. 874), Texas kangaroo rats may
occasionally enter agricultural fields to gather seeds (Chapman 1972,
p. 879). Similar to other kangaroo rats, the Texas kangaroo rat stores
food items in burrow caches (Chapman 1972, p. 879).
Little is known about this species' reproductive behavior or
physiology (a branch of biology that deals with the functions and
activities of life or of living matter, i.e., organs, tissues, or
cells), although it is known that the species does not hibernate and
evidence suggests it may be capable of breeding throughout the year
(Carter et al. 1985, p. 1).
The first recorded instance of the Texas kangaroo rat was a
specimen collected in 1894 from Clay County, Texas (Merriam 1894, p.
109). In 1905, this species was reported from the Chattanooga vicinity,
Comanche County, Oklahoma (Bailey 1905, pp. 148-149). Since these early
records, additional Texas kangaroo rat sightings have been recorded
from the following counties: Archer, Baylor, Childress, Clay, Cottle,
Foard, Hardeman, Montague, Motley, Wichita, and Wilbarger Counties,
Texas; and Comanche and Cotton Counties, Oklahoma (Dalquest and Collier
1964, pp. 146-147; Packard and Judd 1968, p. 536; Martin and Matocha
1972, pp. 873-876; Cokendolpher et al. 1979, p. 376; Baumgardner 1987,
pp. 285-286; Martin and Matocha 1991, p. 354; Martin 2002, p. 10). A
single, disjunct record was reported from an unverified sighting in
Coryell County, Texas; however, subsequent attempts to confirm its
presence in this region have failed, suggesting the original sighting
was probably false (Martin and Matocha 1972, pp. 874-875; Martin 2002,
p. 10).
The present extent of the Texas kangaroo rat's distribution is
largely unknown, but evidence indicates that the species may inhabit
only half of its former range. Of the 11 Texas counties that once
contained Texas kangaroo rats, it has been suggested that only 5 were
known to support them in 2002: Archer, Childress, Hardeman, Motley, and
Wichita (Martin 2002, p. 10). The petition cites surveys published in
peer-reviewed scientific journals that we deem as reliable information,
and indicates that the species may be extirpated from Oklahoma, having
last been sighted there in 1969 (Baumgardner 1987, pp. 285-286; Moss
and Mehlhop-Cifelli 1990, p. 357; Stangl et al. 1992a, p. 19). However,
more surveys are needed to determine the species' current distribution.
Evaluation of Information for This Finding
Section 4 of the Act (16 U.S.C. 1533) and its implementing
regulations at 50 CFR part 424 set forth the procedures for adding a
species to, or removing a species from, the Federal Lists of Endangered
and Threatened Wildlife and Plants. A species may be determined to be
an endangered or threatened species due to one or more of the five
factors described in section 4(a)(1) of the Act:
(A) The present or threatened destruction, modification, or
curtailment of its habitat or range;
(B) Overutilization for commercial, recreational, scientific, or
educational purposes;
(C) Disease or predation;
(D) The inadequacy of existing regulatory mechanisms; or
(E) Other natural or manmade factors affecting its continued
existence.
In considering what factors might constitute threats, we must look
beyond the exposure of the species to a particular factor to evaluate
whether the species may respond to that factor in a way that causes
actual impacts to the species. If there is exposure to a factor and the
species responds negatively, the factor may be a threat and we attempt
to determine how significant a threat it is. The threat may be
significant if it drives, or contributes to, the risk of extinction of
the species such that the species may warrant listing as endangered or
threatened as those terms are defined by the Act. The identification of
factors that could impact a species negatively may not be sufficient to
compel a finding that substantial information has been presented
suggesting that listing may be warranted. The information should
contain evidence or the reasonable extrapolation that any factor(s) may
be an operative threat that acts on the species to the point that the
species may meet the definition of endangered or threatened under the
Act.
In making this 90-day finding, we evaluated whether information
regarding threats to the Texas kangaroo rat, as presented in the
petition and other information available in our files, is substantial,
thereby indicating that the petitioned action may be warranted. Our
evaluation of this information is presented below.
[[Page 12686]]
A. Present or Threatened Destruction, Modification, or Curtailment of
Its Habitat or Range
Information Provided in the Petition
The petition asserts that present or threatened destruction,
modification, or curtailment of the habitat or range of the Texas
kangaroo rat threatens this species such that listing may be warranted.
It identifies five key components affecting the destruction,
modification, or curtailment of this species' habitat and range:
(1) Conversion of native habitat to cropland;
(2) Loss of historical ecological processes;
(3) Domestic livestock grazing;
(4) Brush control; and
(5) Development and roads.
The petition suggests that crop fields and cultivated land are
uninhabitable by Texas kangaroo rats (WildEarth Guardians 2010, p. 11).
It estimates that greater than 15 percent of the range of the Texas
kangaroo rat is encroached upon by agriculture, with areas in
southwestern Oklahoma being the most impacted (WildEarth Guardians
2010, pp. 11-12); however, the petition did not provide information
regarding current land use trends within this species' range. The
petition also states that human activities have altered the natural
ecological processes within the range of the Texas kangaroo rat and
specifically identifies the extirpation of bison and prairie dogs and
suppression of naturally occurring fires (WildEarth Guardians 2010, pp.
13-16). It claims that these natural factors were historically
responsible for creating and maintaining Texas kangaroo rat habitat,
and that their alteration has negatively impacted the species
(WildEarth Guardians 2010, p. 13). The petition suggests that domestic
livestock grazing has historically been a threat to the Texas kangaroo
rat by promoting the encroachment of weeds and woody shrubs, although
it also suggests alterations in rangeland management techniques may
benefit the species by promoting shortened vegetation and areas of bare
ground (WildEarth Guardians 2010, p. 16). In addition, the petition
suggests that development and roads have encroached on Texas kangaroo
rat habitat (WildEarth Guardians 2010, pp. 16-19), thereby increasing
the risks of predation and direct mortality from vehicle collisions
(WildEarth Guardians 2010, p. 25). However, it did not explicitly
indicate how the encroachment of other urban developments may affect
this species. Lastly, the petition suggests that brush control,
particularly through the use of chemicals, may be responsible for the
degradation of Texas kangaroo rat habitat (WildEarth Guardians 2010, p.
20).
Evaluation of Information Provided in the Petition and Available in
Service Files
The sources cited within the petition provide reliable and accurate
information regarding the potential impacts that the conversion of
native habitat to cropland, the loss of historical ecological
processes, domestic livestock grazing, development and roads, and brush
control may have on the Texas kangaroo rat. However, upon further
examination of the cited materials, we note that the portrayal of this
information within the petition may be misleading, and the information
requires further examination, as it does not adequately address the
potential positive impacts that some of these factors may have on the
Texas kangaroo rat or its habitat. An examination of the materials
cited in the petition and of those contained within our files is
presented below.
One of the primary factors that may be negatively impacting the
Texas kangaroo rat is conversion of native habitat to cropland. The
conversion of native habitat to cropland results in a loss of habitat
because the Texas kangaroo rat does not construct burrows in
agricultural crops (Martin and Matocha 1972, p. 874; Martin 2002, pp.
33-34; Goetze et al. 2007, p. 18; Goetze et al. 2008, p. 313; Nelson et
al. 2009, pp. 119-120). Additionally, in regions with substantial
agricultural development, Texas kangaroo rats can often be found
burrowing along the disturbed shoulder of roads, suggesting the
practice of cultivating crop land to the margins of roads may further
preclude this species from utilizing these areas (Wahl 1987, p. 2;
Martin 2002, pp. 35-36). Further, given their relatively small home
ranges and movement patterns (Roberts and Packard 1973, pp. 958-961;
Stangl and Schafer 1990, p. 6), the fragmentation of suitable habitat
by agricultural cultivation of land may isolate Texas kangaroo rats
from other nearby populations, thereby reducing genetic exchange (Wahl
1987, p. 2). Over time, reduced genetic exchange may cause isolated
populations to die out from the deleterious effects of inbreeding
(Keller and Waller 2002, pp. 230-241). Thus, there appears to be
substantial information indicating that loss of habitat due to
conversion of native rangeland into cropland may be negatively
impacting the species. Based on the above evaluation, we find that the
information provided in the petition, as well as other information
readily available in our files, presents substantial scientific or
commercial information indicating that the loss of burrowing habitat
due to the conversion of rangeland to cropland may pose a threat to the
Texas kangaroo rat such that the petitioned action may be warranted.
The petition also asserts that, in addition to loss of burrowing
habitat, the conversion of native rangeland to cropland results in a
loss of foraging habitat, which has been presumed to be a key factor in
the disappearance of the Texas kangaroo rat from Oklahoma (Moss and
Melhop-Cifelli 1990, p. 357). However, the use of cropland for foraging
is not completely understood. Goetze et al. (2008, p. 313) did not
record any Texas kangaroo rats foraging in, or otherwise utilizing,
adjacent wheat fields, either before or after harvesting. In contrast,
through an analysis of cheek pouch contents, Chapman (1972, pp. 878-
879) indicated Texas kangaroo rats foraged in adjacent oat fields
following harvest. Bailey (1905, p. 149) found a single specimen whose
pouches contained grain from a nearby corn field. Therefore, based on
information in our files, there is evidence that Texas kangaroo rats
will forage in croplands. Thus, the conversion of rangeland to cropland
does not seem to result in a loss of foraging habitat. Based on the
above evaluation, we find that the information provided in the
petition, as well as other information readily available in our files,
does not present substantial scientific or commercial information
indicating that the loss of foraging habitat due to the conversion of
rangeland to cropland may pose a threat to the Texas kangaroo rat such
that the petitioned action may be warranted.
Free-ranging bison, prairie dog colonies, and naturally occurring
fires contributed to creation and maintenance of prairies containing
short vegetation and areas of bare ground, the preferred habitat of the
Texas kangaroo rat (Stangl et al. 1992b, pp. 33-34; Nelson et al. 2009,
p. 128). The propensity of the Texas kangaroo rat to inhabit disturbed
areas may be indicative of the species having evolved in the presence
of these three factors. The petition asserts that removal of bison,
prairie dogs, and naturally occurring fires from the historical range
of the Texas kangaroo had a negative impact on this species. However,
information in our files indicates that Texas kangaroo rats occur in
habitats without bison, prairie dogs colonies, or natural fires
(Dalquest and Collier 1964, pp. 146-147; Packard and
[[Page 12687]]
Judd 1968, p. 536; Martin and Matocha 1972, pp. 873-876; Cokendolpher
et al. 1979, p. 376; Baumgardner 1987, pp. 285-286; Martin and Matocha
1991, p. 354; Martin 2002, p. 10). In addition, given the persistence
of Texas kangaroo rats in areas without bison, prairie dog colonies, or
natural fires, it appears that, while each may help create and maintain
suitable habitat, they are not essential for its survival. In the
absence of these historical processes, heavy cattle grazing and
anthropomorphic disturbances may create suitable Texas kangaroo rat
habitat (Stangl et al. 1992b, p. 34; Martin 2002, p. 35; Goetze et al.
2007, p. 19; Nelson et al. 2009, pp. 120-129). Therefore, information
provided by the petitioner and in our files does not indicate that the
lack of free-ranging bison, prairie dog colonies, and naturally
occurring fires has contributed to loss of habitat for the Texas
kangaroo rat. Based on the above evaluation, we find that the
information provided in the petition, as well as other information
readily available in our files, fails to meet our standard for
substantial scientific or commercial information indicating that the
lack of free-ranging bison, prairie dog colonies, and naturally
occurring fires may pose a threat to the Texas kangaroo rat such that
the petitioned action may be warranted.
Domestic livestock grazing was noted by the petition as a factor
negatively impacting the Texas kangaroo rat by promoting the
encroachment of weeds and woody shrubs. The petitioner cites Hafner
(1998, p. 16) in suggesting that the Texas kangaroo rat is vulnerable
to grazing pressures because grazing presumably degrades grasslands. We
believe this claim lacks substantiation because grazing that produces
areas of short vegetation interspersed with bare ground is conducive to
Texas kangaroo rat inhabitation (Stangl et al. 1992b, p. 32; Martin
2002, p. 34; Nelson et al. 2009, p. 120). On the other hand, ranch
management practices that are designed to maintain dense grass stands
lacking areas of bare ground are not suitable for maintaining Texas
kangaroo rat habitat (Goetze 2001, pp. 1-3; Martin 2002, p. 34; Nelson
et al. 2009, p. 120). Under light to moderate grazing pressure,
localized areas of heavy grazing and soil disturbance can be achieved
through the strategic placement of supplemental feeders and stock tanks
(Stangl et al. 1992b, pp. 32-34).
The petition also claims that cattle grazing can lead to rangeland
encroachment by weeds, woody shrubs, and invasive plants that can be
detrimental to the Texas kangaroo rat (WildEarth Guardians 2010, p.
16). According to information we reviewed, the mere presence of woody
shrubs, weedy species, and nonnative plants does not preclude the
presence of Texas kangaroo rats. In fact, a study of cheek pouch
contents indicated that a wide variety of plants, including several
nonnative species, serve as possible food sources for the Texas
kangaroo rat (Dalquest and Collier 1964, pp. 147-148; Chapman 1972, pp.
878-879; Carter et al. 1985, p. 1), and that woody forbs may collect
wind-blown soil in which this species constructs its burrows (Nelson et
al. 2009, p. 120).
We believe that, besides heavy grazing regimes, burrowing and
forage habitat for Texas kangaroo rats is not negatively impacted by
livestock grazing. Based on the above evaluation, we find that the
information provided in the petition, as well as other information
readily available in our files, fails to meet our standard for
substantial scientific or commercial information indicating that
domestic livestock grazing may pose a threat to the Texas kangaroo rat
such that the petitioned action may be warranted.
The petition suggests that brush control, particularly through the
use of chemicals, is responsible for the degradation of Texas kangaroo
rat habitat (WildEarth Guardians 2010, p. 20). Although not
scientifically assessed, Chapman (1972, p. 879) found that chemically
treated brush control sites showed little evidence of Texas kangaroo
rat inhabitation, and indicated additional studies should be conducted
to quantify the effects of range and agricultural practices on this
species. In contrast, Stangl et al. (1992b, p. 31) found that chemical
brush control actually enhanced Texas kangaroo rat habitat by providing
more bare ground and grassy areas that the species prefers (Goetze et
al. 2007, p. 18). Further, Texas kangaroo rats have also been shown to
preferentially construct burrows on elevated soil mounds, including
those that formed around old brush piles (Nelson et al. 2009, pp. 124,
128). Thus, we find no evidence that brush control, even through the
use of chemicals, is having a detrimental effect on Texas kangaroo rat
habitat. Based on the above evaluation, we find that the information
provided in the petition, as well as other information readily
available in our files, fails to meet our standard for substantial
scientific or commercial information indicating that brush control may
pose a threat to the Texas kangaroo rat such that the petitioned action
may be warranted.
The petition suggests that development and roads have encroached on
Texas kangaroo rat habitat (WildEarth Guardians 2010, pp. 16-19),
thereby increasing the risks of predation and direct mortality from
vehicle collisions (WildEarth Guardians 2010, p. 25). While development
and road construction have increased throughout the historic range of
the Texas kangaroo rat since its description by Merriam in 1894, the
impact of urban expansion on the species' status is unclear. Brock and
Kelt (2004, pp. 638-639) suggest that roads increase the likelihood of
predation of Texas kangaroo rats and facilitate invasion by exotic
plants. Martin (2002, p. 35) found that Texas kangaroo rats extensively
utilize suitable, previously disturbed areas along the edges of
roadsides, including roadside habitats within agricultural areas, where
they may otherwise be precluded. Others have noted that Texas kangaroo
rats (Roberts and Packard 1973, p. 960; Stangl and Schafer 1990, p. 11;
Stangl et al. 1992b, p. 34), and other similar species (Brock and Kelt
2004, pp. 633-639), may preferentially use dirt roads as migration
corridors. Also, it is well established that nighttime road surveys are
an easy and effective way to determine the presence of the Texas
kangaroo rat, suggesting they do not entirely avoid these areas.
Although there are reports of specimens killed by vehicular traffic
(Dalquest and Collier 1964, p. 146; Jones et al. 1988, p. 249),
information we reviewed suggests that this is not having a negative
impact on the overall species' status.
Additionally, Texas kangaroo rats are nocturnal and remarkably
tolerant of human presence (Stangl et al. 2005, p. 140; Goetze et al.
2008, p. 310), suggesting that urban development around otherwise
suitable habitat may not preclude their inhabitance. There is some
indication that Texas kangaroo rats are less active on brightly moonlit
nights and more active during the darkest times of the night (Jones et
al. 1988, p. 253; Stangl and Schafer 1990, p. 4; Martin 2002, p. 31),
suggesting light may negatively affect this species. In contrast,
others have noted this species is tolerant of higher light levels
(Bailey 1905, p. 149; Goetze et al. 2008, p. 314). Based on the above
evaluation, we find that the information provided in the petition, as
well as other information readily available in our files, fails to meet
our standard for substantial scientific or commercial information
indicating that development and roads may pose a threat to the Texas
kangaroo rat such that the petitioned action may be warranted.
In conclusion, the fragmentation of the native landscape by
conversion of
[[Page 12688]]
land to cropland has likely impacted the Texas kangaroo rat by reducing
burrowing habitat. This threat, in conjunction with the species'
limited long-distance mobility, may be impairing the species' ability
to maintain viable populations by genetically isolating them from one
another (Wahl 1987, p. 1). However, the effects of cattle grazing,
encroachment of roads and development, and brush control methods on
Texas kangaroo rat habitat are less certain, and may be beneficial
under certain circumstances. Similarly, it appears that loss of
historical disturbance by bison, prairie dogs, and fire may be offset
by heavy grazing of domestic cattle. We will further analyze potential
threats under Factor A during our status review for this species.
Therefore, we find that the information presented in the petition,
as well as other information readily available in our files, presents
substantial scientific or commercial information to indicate that the
Texas kangaroo rat may warrant listing due to present or threatened
destruction, modification, or curtailment of the species' habitat or
range, primarily due to conversion of native rangeland to agricultural
cropland.
B. Overutilization for Commercial, Recreational, Scientific or
Educational Purposes
Information Provided in the Petition
The petition claims that early scientific overutilization involving
the collection and preservation of Texas kangaroo rat specimens may
have had an impact on its range contraction (WildEarth Guardians 2010,
p. 20). As indicated in the petition, many early scientific studies of
Texas kangaroo rats resulted in preservation of specimens as museum
vouchers (Dalquest and Collier 1964, p. 146; Packard and Judd 1968, pp.
535-536; Martin and Matocha 1972, p. 876; Cokendolpher et al. 1979, p.
376; Hamilton et al. 1987, p. 776).
Evaluation of Information Provided in the Petition and Available in
Service Files
We acknowledge that the historical collection and preservation of
Texas kangaroo rat specimens were lethal means of collection; however,
we have no evidence that collections occurred at a level that impacted
the status of the species. Further, current collection methods have
resulted in fewer deaths. More recent studies have used live-trapping
techniques, although Texas kangaroo rats left overnight in traps are
susceptible to cold nightly temperatures and may die following release
(Stangl and Schafer 1990, p. 9). In conclusion, we acknowledge that
scientific studies have resulted in the death of Texas kangaroo rats,
but neither the petition nor information within our files presents
substantial scientific or commercial information indicating that
collection was, or is, occurring at a level that impacts the overall
status of the species. Therefore, we find the petition does not present
substantial scientific or commercial information to indicate that
overutilization for commercial, recreational, scientific, or
educational purposes may present a threat to the Texas kangaroo rat
such that the petitioned action may be warranted.
C. Disease or Predation
Information Provided in the Petition
The petition did not identify disease or predation as factors
impacting Texas kangaroo rats. In fact, the petition suggests that
there are no records of natural predation acting as a threat to Texas
kangaroo rats. However, the petition identifies several Texas kangaroo
rat parasites, but indicates that disease is not currently known to be
a major mortality factor. The petition also recommends further
investigation of the potential for sylvatic plague to affect the Texas
kangaroo rat (WildEarth Guardians 2010, pp. 20-21).
Evaluation of Information Provided in the Petition and Available in
Service Files
After reviewing the original source material cited with the
petition, we find that the information within the petition is reliable
and accurate regarding Texas kangaroo rat disease and predation.
Information in our files suggests that the potential for infection from
sylvatic plague does exist, but the disease rarely causes mortality in
Texas kangaroo rats (Martin 2002, p. 30). A number of external
parasites (Thomas et al. 1990, pp. 111-114) and an internal parasite
(Pfaffenberger and Best 1989, pp. 76-80) are known to use the Texas
kangaroo rat as a host, but their effects on the survival and
proliferation of this species are not known. Even though the Texas
kangaroo rat is exposed to disease, there is no evidence to indicate
that the species is responding to the factor in a way that causes
actual impacts to the species.
Similarly, there is no evidence indicating predation is having an
impact on the species. Stangl et al. (2005, p. 139) found that the
Texas kangaroo rat was underrepresented in the diet of barn owls, and
attributed this partly to the auditory and locomotion abilities of the
rat, which allowed it to escape predation. Remnants of a similar
species, the Ord's kangaroo rat (Dipodomys ordii), were found in only
4.3 percent of coyote scats in south Texas, suggesting coyotes may not
depend heavily on kangaroo rats as a part of their diet (Martin 2002,
p. 29). In addition, domesticated cats have been found to prey on the
Texas kangaroo rats, but only to a limited extent (Martin 2002, p. 29).
Although available information in the petition and our files suggests
that Texas kangaroo rats are susceptible to predation, the information
we reviewed does not suggest that predation occurs at levels that act
as a significant limiting factor to the species throughout its range.
We reviewed information in our files and the information provided
by the petitioners, and did not find substantial information to
indicate that disease or predation may be outside the natural range of
variation such that either could be considered a threat to the Texas
kangaroo rat. Therefore, we find the petition does not present
substantial scientific or commercial information to indicate that
disease or predation may present a threat to the Texas kangaroo rat
such that the petitioned action may be warranted.
D. Inadequacy of Existing Regulatory Mechanisms
Information Provided in the Petition
The petition claims there are insufficient existing regulatory
mechanisms protecting the Texas kangaroo rat. While this species is
listed as threatened under Texas Parks and Wildlife Code, Chapter 68,
this status does not prevent the destruction or degradation of Texas
kangaroo rat habitat (WildEarth Guardians 2010, p. 21).
Evaluation of Information Provided in the Petition and Available in
Service Files
We find that the information within the petition, although limited,
is reliable and accurate regarding the inadequacies of existing
regulatory mechanisms in protecting the Texas kangaroo rat. As
discussed above under Factor A, Texas kangaroo rats do not inhabit
cultivated cropland; thus, the expansion of cultivated cropland may
fragment existing populations until they are no longer viable (Wahl
1987, p. 1). The ``threatened'' status of the Texas kangaroo rat under
Texas Parks and Wildlife Code does not preclude further land conversion
in areas occupied by the species. Therefore, we find that the
information provided in petition, as
[[Page 12689]]
well as other information readily available in our files, presents
substantial scientific or commercial information indicating the
petitioned action may be warranted due to the inadequacy of existing
regulatory mechanisms.
E. Other Natural or Manmade Factors Affecting the Species' Continued
Existence
Information Provided in the Petition
The petition claims that road construction, extermination programs,
and climate change are, or may become, threats to the continued
existence of the Texas kangaroo rat (WildEarth Guardians 2010, pp. 21-
26). The effects of road construction on this species are evaluated
above under Factor A. The petition suggests that kangaroo rat
extermination programs in the 1920s and 1930s were initiated because
these species were implicated in the ongoing desertification of
rangeland. The petition also provides evidence of climate change trends
(WildEarth Guardians 2010, pp. 21-24) and suggests that the ensuing
ecological changes would make this species' current range more
unsuitable for its inhabitation.
Evaluation of Information Provided in the Petition and Available in
Service Files
After reviewing the original source material cited in the petition,
we find that these sources are reliable and accurate. However, we
believe that the portrayal of this information within the petition
requires further examination as described below.
The petitioner claims that extermination programs may be
threatening the continued existence of the Texas kangaroo rat. Sjoberg
et al. (1984, p. 13) suggested that kangaroo rats, particularly the
banner-tailed kangaroo rat (Dipodomys spectabilis), whose mound system
is extensive, were treated by various methods to remove them from
rangelands. However, the Texas kangaroo rat does not make extensive
mounds, and its exceptionally small burrow entrances occupy very little
of the landscape (Bailey 1905, p. 149; Carter et al. 1985, p. 1; Martin
2002, p. 3). This species also has minimal economic impact on
agriculture (Martin 2002, p. 3). Therefore, it is unlikely the Texas
kangaroo rat was historically subjected to extensive eradication
efforts, and there is no evidence presented by the petitioner or
readily available in our files indicating that the Texas kangaroo rat
was impacted by eradication efforts aimed at other species. In
addition, the Texas kangaroo rat is currently protected as a nongame
species under Texas Parks and Wildlife Code, Chapter 68, making such
eradication efforts illegal. Therefore, we found no evidence that
extermination programs are negatively impacting the Texas kangaroo rat.
Also, the petition asserts that climate change trends will make the
current range more unsuitable for the Texas kangaroo rat to inhabit
(WildEarth Guardians 2010, pp. 21-24). The petitioner presents
information that plant and animal communities are expected to shift
toward the poles or increase in altitude with increasing global
temperatures and drought conditions (Parmesan et al. 2000, p. 443;
Cameron and Scheel 2001, p. 676; Root and Schneider 2002, pp. 22-23;
Karl et al. 2009, pp. 72, 132). However, the petition does not provide
substantial information indicating how pole-ward shifts in plant and
animal communities would negatively impact the Texas kangaroo rat. We
believe that increasing global temperatures and drought conditions will
likely have little impact on kangaroo rats because they are
physiologically and behaviorally well adapted to warm, arid landscapes
(Sjoberg et al. 1984, p. 12). In addition, Texas kangaroo rats do not
appear to be particularly dependent on any single type of vegetation
for survival, and are capable of adapting to changing vegetation as is
evident from their behavior of gathering nonnative plant seeds
(Dalquest and Collier 1964, pp. 147-148; Chapman 1972, pp. 878-879). As
such, the information we reviewed does not indicate that climate
change-induced, pole-ward shifts in plant and animal communities would
result in the Texas kangaroo rat's current range becoming unsuitable
for the species to inhabit.
The petition further claims that climate change models show a loss
of Texas kangaroo rat habitat. Cameron and Scheel (2001, p. 664)
predicted that between 48 and 80 percent of suitable Texas kangaroo rat
habitat would be lost under two different climate change models. These
losses were estimated from a 2001 baseline of approximately 103,400
square kilometers (km\2\) (39,923 square miles (mi\2\)) of suitable
Texas kangaroo rat habitat, and following correction for vegetation
preferences (Cameron and Scheel 2001, p. 664). However, the combined
acreage of the 11 Texas counties from which the Texas kangaroo rat has
been recorded is approximately 24,500 km\2\ (9,460 mi\2\), a value much
closer to their pre-corrected habitat estimate of 21,200 km\2\ (Cameron
and Scheel 2001, p. 655). This suggests that the model may have
overestimated current suitable habitat. In addition, the study found
vegetation preference significantly affected habitat suitability for
this species while soil preferences were not significant (Cameron and
Scheel 2001, p. 655). In contrast, Shaw (1990, p. 16) found Texas
kangaroo rat distributions to vary significantly with soil type.
Furthermore, Cameron and Scheel (2001, p. 659) did not assess habitat
outside of Texas. If animals are generally predicted to move pole-ward
as a result of climate change, the Texas kangaroo rat may partially
relocate to Oklahoma, which was not included as part of the Cameron and
Scheel (2001) study. Even though Cameron and Scheel (2001, p. 664)
predicted theoretically severe implications for climate change on the
Texas kangaroo rat based on their models, we could find no evidence to
substantiate their claims. Additional analysis is needed to determine
the effect of these impacts on the Texas kangaroo rat. We will further
analyze the potential impacts of climate change on the species during
our status review.
Therefore, we find the petition does not present substantial
scientific or commercial information indicating that other natural or
manmade factors may affect the continued existence of the Texas
kangaroo rat such that the petitioned action may by warranted.
Finding
On the basis of our determination under section 4(b)(3)(A) of the
Act, we find that the petition presents substantial scientific or
commercial information indicating that listing the Texas kangaroo rat
throughout its entire range may be warranted. This finding is based on
potential threats posed under Factor A, The Present or Threatened
Destruction, Modification, or Curtailment of Its Habitat or Range, and
Factor D, The Inadequacy of Existing Regulatory Mechanisms.
Specifically, we find that the loss of burrowing habitat and genetic
isolation of populations due to the conversion of native rangeland to
agricultural cropland, and the inadequacy of existing regulatory
mechanisms to protect against such land conversion, may pose a threat
to the Texas kangaroo rat throughout all or a significant portion of
its range, such that the petitioned action may be warranted. The
information provided under Factors B, C, and E was not substantial.
Because we have found that the petition presents substantial
information indicating that listing the Texas kangaroo rat may be
warranted,
[[Page 12690]]
we are initiating a status review to determine whether listing the
Texas kangaroo rat under the Act is warranted.
The ``substantial information'' standard for a 90-day finding
differs from the Act's ``best scientific and commercial data'' standard
that applies to a status review to determine whether a petitioned
action is warranted. A 90-day finding does not constitute a status
review under the Act. In a 12-month finding, we will determine whether
a petitioned action is warranted after we have completed a thorough
status review of the species, which is conducted following a
substantial 90-day finding. Because the Act's standards for 90-day and
12-month findings are different, as described above, a substantial 90-
day finding does not mean that the 12-month finding will result in a
warranted finding.
References Cited
A complete list of references cited is available on the Internet at
http://www.regulations.gov and upon request from the Arlington
Ecological Services Field Office (see FOR FURTHER INFORMATION CONTACT).
Author
The primary author of this notice is a staff member of the
Arlington Ecological Services Field Office (see FOR FURTHER INFORMATION
CONTACT).
Authority
The authority for this action is the Endangered Species Act of
1973, as amended (16 U.S.C. 1531 et seq.).
Dated: February 16, 2011.
Rowan W. Gould,
Acting Director, U.S. Fish and Wildlife Service.
[FR Doc. 2011-5177 Filed 3-7-11; 8:45 am]
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