[Federal Register Volume 76, Number 45 (Tuesday, March 8, 2011)]
[Proposed Rules]
[Pages 12683-12690]
From the Federal Register Online via the Government Publishing Office [www.gpo.gov]
[FR Doc No: 2011-5177]


-----------------------------------------------------------------------

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.

-----------------------------------------------------------------------

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:
    <bullet> 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.
    <bullet> 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]
BILLING CODE 4310-55-P