[Federal Register Volume 76, Number 194 (Thursday, October 6, 2011)]
[Proposed Rules]
[Pages 62214-62258]
From the Federal Register Online via the Government Publishing Office [www.gpo.gov]
[FR Doc No: 2011-25473]



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Vol. 76

Thursday,

No. 194

October 6, 2011

Part III





Department of the Interior





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Fish and Wildlife Service





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50 CFR Part 17





Endangered and Threatened Wildlife and Plants; 12-Month Finding on a 
Petition To List the Mohave Ground Squirrel as Endangered or 
Threatened; Proposed Rule

  Federal Register / Vol. 76 , No. 194 / Thursday, October 6, 2011 / 
Proposed Rules  

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DEPARTMENT OF THE INTERIOR

Fish and Wildlife Service

50 CFR Part 17

[Docket No. FWS-R8-ES-2010-0006; 92210-1111-0000-B2]


Endangered and Threatened Wildlife and Plants; 12-Month Finding 
on a Petition To List the Mohave Ground Squirrel as Endangered or 
Threatened

AGENCY: Fish and Wildlife Service, Interior.

ACTION: Notice of 12-month petition finding.

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SUMMARY: We, the U.S. Fish and Wildlife Service (Service), announce a 
12-month finding on a petition to list the Mohave ground squirrel 
(Spermophilus mohavensis) as endangered or threatened under the 
Endangered Species Act of 1973, as amended (Act). After review of the 
best available scientific and commercial information, we find that 
listing the Mohave ground squirrel is not warranted at this time. 
However, we ask the public to continue to submit to us any new 
information that becomes available concerning the threats to the Mohave 
ground squirrel or its habitat at any time.

DATES: The finding announced in this document was made on October 6, 
2011.

ADDRESSES: This finding is available on the Internet at http://www.regulations.gov at Docket Number FWS-R8-ES-2010-0006 and at http://www.fws.gov/ventura/. Supporting documentation we used in preparing 
this finding is available for public inspection, by appointment, during 
normal business hours at the U.S. Fish and Wildlife Service, Ventura 
Fish and Wildlife Office, 2493 Portola Road, Suite B, Ventura, CA 
93003. Please submit any new information, materials, comments, or 
questions concerning this finding to the above address.

FOR FURTHER INFORMATION CONTACT: Michael McCrary, Listing and Recovery 
Program Coordinator, U.S. Fish and Wildlife Service, Ventura Fish and 
Wildlife Office (see ADDRESSES); by telephone at 805-644-1766; or by 
facsimile at 805-644-3958. If you use a telecommunications device for 
the deaf (TDD), call the Federal Information Relay Service (FIRS) at 
800-877-8339.

SUPPLEMENTARY INFORMATION:

Background

    Section 4(b)(3)(B) of the Act (16 U.S.C. 1531 et seq.) requires 
that, for any petition to revise the Federal Lists of Endangered and 
Threatened Wildlife and Plants that contains substantial scientific or 
commercial information that listing may be warranted, we make a finding 
within 12 months of the date of receipt of the petition. In this 
finding, we determine whether the petitioned action is: (a) Not 
warranted, (b) warranted, or (c) warranted, but the immediate proposal 
of a regulation implementing the petitioned action is precluded by 
other pending proposals to determine whether species are endangered or 
threatened, and expeditious progress is being made to add or remove 
qualified species from the Federal Lists of Endangered and Threatened 
Wildlife and Plants. Section 4(b)(3)(C) of the Act requires that we 
treat a petition for which the requested action is found to be 
warranted but precluded as though resubmitted on the date of such 
finding, that is, requiring a subsequent finding to be made within 12 
months. We must publish these 12-month findings in the Federal 
Register.

Previous Federal Actions

    On December 13, 1993, the Service received a petition dated 
December 6, 1993, from Dr. Glenn R. Stewart of California Polytechnic 
State University, Pomona, California, requesting the Service list the 
Mohave ground squirrel as a threatened species. At that time, the 
species was a category 2 candidate (November 15, 1994; 59 FR 58982), 
and was first included in this category on September 18, 1985. Category 
2 included taxa for which information in the Service's possession 
indicated that listing the species as endangered or threatened was 
possibly appropriate, but for which sufficient data on biological 
vulnerability and threats were not available to support a proposed 
listing rule. On September 7, 1995, we published our 90-day petition 
finding, which determined that the 1993 petition did not present 
substantial information indicating that the petitioned action may be 
warranted (60 FR 46569).
    On September 5, 2005, we received a petition, dated August 30, 
2005, from the Defenders of Wildlife and Dr. Glenn R. Stewart to list 
the Mohave ground squirrel as an endangered species in accordance with 
section 4 of the Act. It also requested that critical habitat be 
designated concurrent with the listing of the Mohave ground squirrel. 
The petition clearly identified itself as such and included the 
requisite identification information for the petitioners, as required 
in 50 CFR 424.14(a).
    On April 27, 2010, the Service made its 90-day finding (75 FR 
22063), concluding that the petition presented substantial scientific 
or commercial information to indicate that listing the Mohave ground 
squirrel may be warranted, announced the initiation of a status review 
of this species, and solicited comments and information to be provided 
in connection with the status review by June 28, 2010. This notice 
constitutes our 12-month finding regarding the petition to list the 
Mohave ground squirrel.

Species Information

Species Description
    The Mohave ground squirrel is a medium-sized squirrel. Total 
length, including the tail, is about 9 inches (in) (23 centimeters 
(cm)), tail length is about 2.5 in (6.4 cm), and weight is about 3.5 
ounces (104 grams). The upper body is grayish brown, pinkish gray, 
cinnamon gray, and pinkish cinnamon, without stripes or fleckings. The 
underparts of the body and the tail are silvery white and the tail is 
bushy (Grinnell and Dixon 1918, p. 667). The skin is darkly pigmented 
and dorsal hair tips are multi-banded. The Mohave ground squirrel has a 
winter and summer pelage (coat). In summer the pelage is coarser and 
shorter, the sides of the face paler, and the underbelly whiter than 
the winter pelage. The two sexes appear to be alike in color and 
measurements (Grinnell and Dixon 1918, p. 667).
    Two other species of small ground squirrels occur within the range 
of the Mohave ground squirrel, the antelope ground squirrel 
(Ammospermophilus leucurus) and the round-tailed ground squirrel 
(Xerospermophilus tereticaudus). The three species are different in 
appearance. Although similar in size to the Mohave ground squirrel, the 
antelope ground squirrel is grayish brown in color, with a white side 
stripe and a black band on the underside of the tail near the tip 
(Ingles 1965, pp. 169-171). The round-tailed ground squirrel has a 
unicolored tail that is cylindrical or round and not bushy, and a 
larger body than the Mohave ground squirrel (Ingles 1965, p. 171). 
However, its skull is significantly smaller than that of the Mohave 
ground squirrel in 18 of 20 cranial characteristics (Best 1995, p. 
508). Mohave and antelope ground squirrels occur sympatrically 
(occupying the same or overlapping geographic areas without 
interbreeding) in the same habitat (Aardahl and Roush 1985, p. 20), 
while round-tailed ground squirrels overlap only along the eastern edge 
of the Mohave ground squirrel's range (see ``Nomenclature and 
Taxonomy'' section below).

[[Page 62215]]

Nomenclature and Taxonomy
    The scientific name of the Mohave ground squirrel was changed from 
Spermophilus mohavensis to Xerospermophilus mohavensis with the 
publication of a review of the available research on morphological, 
genetic, cytogenetic, ecological, and behavioral attributes in the 
genus Spermophilus (Helgen et al. 2009, p. 273).
    The Mohave ground squirrel is a distinct, full species with no 
recognized subspecies. It was discovered in 1886 by Frank Stephens 
(Grinnell and Dixon 1918, p. 667) and described by Merriam (1889, p. 
15). The type specimen is from near Rabbit Springs, San Bernardino 
County, California, about 15 miles (mi) (24.1 kilometers (km)) east of 
Hesperia (Grinnell and Dixon 1918, p. 667).
    The closest relative of the Mohave ground squirrel is the round-
tailed ground squirrel (Bell et al. 2009, p. 5; Helgen et al. 2009, p. 
293). Until 1977, the ranges of these two species were thought to be 
adjacent to each other but not overlapping (Hall and Kelson 1959, p. 
358). However, Wessman (1977, p. 10) determined that the eastern edge 
of the geographic range of the Mohave ground squirrel overlapped the 
western edge of the round-tailed ground squirrel (Wessman 1977, pp. 12-
13). He identified several areas of contact between the two species and 
identified one area near Helendale, San Bernardino County, California, 
as a possible zone of hybridization between the species. He observed 
morphological characteristics of both species exhibited in a few of the 
squirrels captured there (e.g., long, narrow tail with white on the 
underside) (Wessman 1977, p. 13). However, in 2009, Bell et al. (p. 11) 
found no evidence of mitochondrial DNA introgression between the Mohave 
ground squirrel and the round-tailed ground squirrel, including the 
three individuals identified as backcross individuals based on allozyme 
(form of an enzyme that differs in amino acid sequence) and karyotypic 
(the shape, type, number, and order of a species' chromosomes) data 
from Hafner and Yates (1983). We are not aware of any information that 
would indicate hybridization occurs with the sympatric antelope ground 
squirrel.
Range and Distribution
    The Mohave ground squirrel is endemic to the western part of the 
Mojave Desert, in portions of Inyo, Kern, Los Angeles, and San 
Bernardino Counties, California. It has one of the smallest ranges of 
any species of ground squirrel in North America (Hoyt 1972, p. 3). We 
define range as the geographical area within which a species may be 
found.
    Aspects of the Mohave ground squirrel's biology and behavior make 
individuals of the species difficult to observe, trap, and count, which 
in part explains why the range of the species has increased over time 
(see below). Mohave ground squirrels are only active and above ground 
for part of the year (generally February through August) and therefore 
can only be trapped and observed during this time. They spend much of 
the year underground and in a state of dormancy (see ``Active Season 
and Dormancy'' section). The length of the active season and movements 
of Mohave ground squirrels may also be affected by rainfall amounts. 
The number of individuals in an area appears to decline during dry 
years, and movements and home range size shrink (Harris and Leitner 
2004, p. 521). Thus, if traps are set during a dry year, the reduced 
movements of Mohave ground squirrels and reduced densities or local 
extirpations make it less likely that the traps are located when and 
where they will capture Mohave ground squirrels. Conversely, if traps 
are set during a wet year when home ranges are larger, the Mohave 
ground squirrel may avoid the baited traps because of the increased 
availability of forage.
    Because most surveys for the Mohave ground squirrel have been only 
1 year in duration, this limited survey duration makes it difficult to 
assess population trend for a species whose numbers, movements, and 
``trapability'' can fluctuate greatly among years (Brooks and Matchett 
2002, p. 171). These factors in combination have made it difficult to 
determine the boundaries of the species' range, its distribution within 
the range, and population trends (see ``Abundance and Trends'' 
section). This has been further complicated because the vast majority 
of the information currently available on the distribution and 
abundance of Mohave ground squirrels is based on the California 
Department of Fish and Game (CDFG) survey protocol, which has been 
known to not detect squirrels when other methods have shown them to be 
present (see ``Abundance and Trend'' section below).
    In 1938, Howell (1938, p. 184) published a map of the range of the 
Mohave ground squirrel that included the western Antelope Valley to an 
area 15 mi (25.2 km) west of Barstow. In 1977, Wessman surveyed for the 
Mohave ground squirrel along much of its eastern boundary and found the 
species' range extended 1,152,000 ac (466,200 ha) farther east and 
south than previously reported (Wessman 1977, p. 4).
    For this 12-month finding, the Service is defining the range of the 
Mohave ground squirrel as about 5,319,000 acres (ac) (2,152,532 
hectares (ha)) (Service calculations) (see Map 1). The range is bounded 
on the south and west by the San Bernardino, San Gabriel, Tehachapi, 
and Sierra Nevada mountain ranges, although the species occurs in 
canyons in the eastern foothills of the Sierra Nevada up to 5,600 feet 
(ft) (1,706 meters (m)) (Gustafson 1993, pp. 56-57; Laabs 1998, p. 1). 
The range is bounded on the north and east by Owens Lake and the Mojave 
River/Lucerne Valley, respectively (Leitner 2008, p. 18). Howell (1938, 
p. 184) and Aardahl and Roush (1985, p. 3) included the Antelope Valley 
west of Palmdale and Lancaster in the range of the Mohave ground 
squirrel (see Map 1).
    The range map in the petition did not include the western Antelope 
Valley because there are no definite records of the species in that 
area. However, for several reasons, we included the western Antelope 
Valley in our range of the Mohave ground squirrel. First, older reports 
and scientific papers on the Mohave ground squirrel included this area 
in the range of the species (e.g., Howell 1938, p. 184; Aardahl and 
Roush 1985, p. 3). Second, although portions of this area are now used 
for agriculture and livestock grazing, suitable habitat still remains 
and may be connected to currently occupied habitat to the east. Third, 
early museum collections of the Mohave ground squirrel did not record 
precise locality data and often used the closest town for reference 
such as ``near Palmdale.'' Frequently, the closest town was several 
miles away and the locality information vague. Fourth, recent visual 
observations of Mohave ground squirrels occurred southwest of Mojave 
(see Map 1) (Leitner 2008, p. 7). Thus, there is some indication that 
the Mohave ground squirrel may have occurred, and may continue to 
occur, in the western portion of the Antelope Valley. Although areas of 
natural habitat within the range of the Mohave ground squirrel have 
been lost or degraded from human activity (see Factor A), the boundary 
of the current range is larger than reported by Howell in 1938.
    The range of the Mohave ground squirrel may be larger than defined 
by the Service, as there have been recent sightings beyond the area 
defined by the Service as the range of the Mohave ground squirrel. 
Although the Mohave ground squirrel has previously been reported at 
elevations up to 5,600 ft (1,706 m) in the canyons in the eastern 
foothills of the Sierra Nevada that open

[[Page 62216]]

to the Mojave Desert (Gustafson 1993, pp. 56-57; Laabs 1998, p. 1), a 
biologist recently reported a Mohave ground squirrel about 10 mi (16.1 
km) south of Weldon (see Map 1) in an interior valley in the Tehachapi 
Mountains (California Natural Diversity Database 2007). Another 
biologist sighted a Mohave ground squirrel in the Panamint Valley, 
which is about 5 mi (8 km) outside the northeastern edge of the range 
(see Map 1) (Threloff 2007 in litt., p.1), whereas Aardahl
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and Roush were unsuccessful in capturing a squirrel here in 1985 
(Gustafson 1993, p. 56). We are not using these two sightings in our 
range calculations because they are anecdotal and fall outside the 
areas previously published about the range of the Mohave ground 
squirrel. Although we have not included these two sightings, they 
indicate that the range of the Mohave ground squirrel may actually be 
larger than previously indicated on range maps or currently defined by 
the Service.
    Within its range, the Mohave ground squirrel has a patchy 
distribution (Hoyt 1972, p. 7), likely caused by differences in 
rainfall, terrain (Zembal and Gall 1980, p. 348), elevation, 
temperature (Gustafson 1993, pp. 56-57), and soils and vegetation 
(Harris and Leitner 2005, p. 189). The habitat requirements of the 
Mohave ground squirrel for feeding, breeding, and sheltering are not 
uniformly spaced throughout its range.
    Leitner (2008, pp. i-A2) collected and analyzed 1,236 unpublished 
observations, field studies, and surveys from 1998 to 2007, including 
both positive and negative findings of trapping efforts using the CDFG 
survey protocol. These surveys were usually performed in association 
with proposed development, because the Mohave ground squirrel is listed 
as threatened under the California Endangered Species Act (CESA) (see 
Factor D, ``State Laws and Regulations''). The survey effort has been 
heavily weighted to the southernmost portion of the species' range 
(Leitner 2008, p. 5), where most of the development in the range of the 
Mohave ground squirrel has occurred and is occurring (see Factor A, 
``Urban and Rural Development''). Approximately 67 percent of the 
surveys were conducted south of State Route 58 (SR-58) (see Map 1), and 
almost half of all surveys were in two areas in the southernmost part 
of the range of the Mohave ground squirrel: The Lancaster-Palmdale area 
and the Adelanto area. Almost all recorded observations of Mohave 
ground squirrels from 1998 to 2007 have been from Edwards Air Force 
Base (EAFB), which is south of SR-58 (see Map 1), or from the central 
and northern portion of the squirrel's range; only a few were observed 
in the southern end of the squirrel's range. However, much of the range 
of the Mohave ground squirrel has not been surveyed (Leitner 2008, p. 
9).
    Leitner (2008, p. 10) identified four areas that he labels as 
``core'' areas for the Mohave ground squirrel. ``Core'' areas have the 
following criteria:
    (1) The species has been present for a substantial period;
    (2) The species is currently found at multiple locations; and
    (3) There is a substantial number of adults representing a viable 
reproductive population.
    Four areas that meet the above criteria are: (1) Coso Range-
Olancha; (2) Little Dixie Wash; (3) EAFB; and (4) Coolgardie Mesa-
Superior Valley (see Map 2). Leitner (2008, p. 1) also described four 
other population areas with multiple recent records of the species, 
although these areas are not known to have Mohave ground squirrels 
present for a substantial period: Pilot Knob, the Desert Tortoise 
Natural Area-Fremont Valley, Boron-Kramer Junction, and Poison Canyon 
(Leitner 2008, p. 34). Together these eight important population areas 
comprise about 606,000 ac (245,240 ha), or 11.4 percent of the species' 
range.
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    Leitner has emphasized the importance of protecting and maintaining 
connectivity between these eight areas for the conservation of the 
Mohave ground squirrel (2008, p. 12). It should be noted, however, that 
these areas have been identified using the data available from limited 
surveys for the Mohave ground squirrel. Much of the range has not been 
surveyed (Leitner 2008, p. 9); therefore, unsurveyed areas may support 
additional important population areas for the Mohave ground squirrel. 
As an example of a recent discovery of an important population area, 
the Poison Canyon area was discovered during a 2006 survey for a 
proposed drainage improvement project

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along a State highway (Sapphos 2006, p. 3-1).
Abundance and Trends
    Data on population abundance and trend for the Mohave ground 
squirrel are limited (Leitner 2008, p. 8). The behavioral 
characteristics of the Mohave ground squirrel make it difficult to 
determine its presence or abundance as it spends much of the year 
underground (see ``Active Season and Dormancy'' section below). Based 
on his observations, Burt (1936, p. 222) estimated the density of 
Mohave ground squirrels in the southern part of their range at 15 to 20 
animals per square mi (5 to 8 animals per square km). Most subsequent 
studies cannot be readily compared with Burt (1936) because they did 
not estimate density of animals (i.e., they either reported the number 
of animals trapped or compared numbers trapped to individual trapping 
efforts (Hoyt 1972, p. 6; Recht 1977, p. 4; Wessman 1977, p. 4; Leitner 
1980, pp. IV-26; Aardahl and Roush 1985, pp. 11-13; Scarry et al. 1996, 
pp. 12-17; Leitner 2001, pp. 13-18, 30-32).
    The only location we are aware of where a population of Mohave 
ground squirrels has been studied in detail for several years is in the 
Coso Region in the northern portion of the species' range (Leitner 
2005, p. 3). Trapping surveys for the Mohave ground squirrel at this 
location were conducted from 1989 to 1996 and from 2001 to 2005. 
However, the estimated population density was only reported for 1990 
and for the period from 1992 to 1996 because of limited sample size in 
other years (Leitner and Leitner 1998, pp. A-3, A-6, A-8, A-9, A-12, A-
15, A-18, and A-22). The number of Mohave ground squirrels that were 
captured varied from year to year, ranging from 10 squirrels trapped in 
2003 to 78 in 1994 (Leitner 2005, p. 3). The number of adult Mohave 
ground squirrels trapped was higher per year during the period 1990-
1996 than during the period 2001-2004 (Leitner 2005, p. 3).
    Researchers have suggested that trends in protocol survey data over 
time could be used to evaluate the status of the species. Brooks and 
Matchett (2002) analyzed the data from 19 reported studies on the 
Mohave ground squirrel in 1918 and during the period 1970-2001. They 
suggested that the Mohave ground squirrel may be undergoing a long-term 
decline as indicated by the decreased trapping success since the mid-
1980s (Brooks and Matchett 2002, p. 176). One possible reason for 
decline is that Mohave ground squirrel populations appear to be 
sensitive to both seasonal and annual rainfall patterns; for example, 
in dry years, reproduction the following spring may be unsuccessful, 
and population numbers and the area occupied by the species may 
decrease (Leitner and Leitner 1998, pp. 29-31; Harris and Leitner 2005, 
p. 520).
    Gustafson (1993, p. 22) reported that prolonged periods of drought 
may result in the loss of Mohave ground squirrels in local areas, 
because no young may be born for one up to several years, and adult 
survivability is reduced by poor habitat conditions to the point where 
the population dies out. In general, the population dynamics of the 
Mohave ground squirrel appear to follow a contraction and expansion 
pattern, i.e., there are local extirpations of squirrel populations 
following drought years and recolonization of these areas with 
consecutive wet years (Harris and Leitner 2005, p. 189). During the 
last few decades, more consecutive years in the western Mojave Desert 
have been dry versus wet (Brooks and Matchett 2002, p. 175), suggesting 
a trend weighted toward extirpations rather than recolonizations. 
However, Brooks and Matchett (2002, p. 176) suggest that factors other 
than, or in addition to, rainfall amount and timing seem to be 
affecting Mohave ground squirrel abundance, such as trapping 
characteristics, trapping protocols, weather conditions, or site 
(habitat) characteristics.
    Leitner (2001, pp. 30-31) conducted a similar comparison of 
trapping results at 11 sites in 1980, 1999, and 2000, and at 19 sites 
in 2004 (Leitner 2005, p. 5). The first study showed a positive 
correlation between rainfall and trapping success prior to 1991, but no 
correlation after that. Both studies reported that trapping success has 
declined and concluded that this indicated a possible decline in the 
distribution and abundance of the Mohave ground squirrel during this 
period, despite periods of above-normal precipitation (Leitner 2001, p. 
32; Brooks and Matchett 2002, p. 176).
    However, the survey protocol is subject to potential inaccuracies, 
such as yielding false negative results or undersampling the population 
(see also Factor D, ``State Laws and Regulations'' section). Mohave 
ground squirrels are difficult to trap (Hoyt 1972, p. 7), and they have 
been observed approaching traps but not entering them (Leitner 2009, 
pers. comm.). For example, in 2009, only one Mohave ground squirrel was 
trapped during two surveys conducted in the Fort Irwin western 
expansion area (Delaney and Leitner 2009, p. 9). However, the detection 
rate for a video detection system, which was used at the same time as 
the trapping was conducted, was much higher; the video system recorded 
nine Mohave ground squirrels compared to the one that was trapped 
(Delaney 2009, pp. 13-14).
Food Habits
    The diet of the Mohave ground squirrel consists of leaves (Recht 
1977, p. 75), flowers, fruits, and seeds (Leitner and Leitner 1992, p. 
12; Gustafson 1993, pp. 77-83) from a variety of plants; they also feed 
on fungi (Burt 1936, p. 223) and arthropods (caterpillars) when 
available (Zembal and Gall 1980, p. 345). When available in spring, 
new, tender, green vegetation makes up nearly all of the diet of the 
Mohave ground squirrel (Best 1995, p. 6). The Mohave ground squirrel is 
also known to eat alfalfa (Best 1995, p. 5).
    The Mohave ground squirrel forages on the ground, in the branches 
of shrubs, and, where present, in Yucca brevifolia (Joshua trees) 
(Johnson no date, p. 1). It caches food in its burrow for future use 
(Johnson no date, p. 1). It obtains water from its diet, but will drink 
water if available (Johnson no date, p. 1).
    Recht (1977, p. 80) categorized the foraging strategy of the Mohave 
ground squirrel as a facultative specialist. Because the availability 
of food resources fluctuates seasonally and annually in the Mojave 
Desert, the Mohave ground squirrel specializes in certain food species 
for short periods, but changes the foods it consumes as their 
availability changes. For example, in March 1994, the diet of the 
Mohave ground squirrel in the northern part of its range was 90 percent 
shrubs, 10 percent forbs (i.e., any herbaceous plant that is not grass 
or grasslike), and less than 1 percent nonnative annual grasses 
(Schismus and Bromus) (Leitner et al. 1995, p. 45). By April, the 
Mohave ground squirrel's diet had changed to 60 percent shrubs, 35 to 
40 percent forbs, and 2 percent grasses (Leitner et al. 1995, p. 48).
    The quantity, variety, and nutritional quality of plant food 
sources available ultimately depend on the amount of rainfall from the 
preceding fall and winter (Aardahl and Roush 1985, p. 22). During 
drought years, there are few-to-no herbaceous native annual forbs 
available, and Mohave ground squirrels must then depend on shrub 
foliage for water and nutrition (Leitner and Leitner 1998, p. 20).
    This foraging strategy provides efficiency and flexibility to 
maximize nutritional and water intake in a changing desert habitat 
(Recht 1977, p. 80). These abilities are needed, as the Mohave ground 
squirrel must increase

[[Page 62220]]

its body weight in spring and early summer to sustain itself during the 
dormant period of mid-summer through winter (Leitner and Leitner 1998, 
p. 33).
Reproduction
    Female Mohave ground squirrels can breed at 1 year of age if 
environmental conditions are favorable (Leitner and Leitner 1998, p. 
28), while males do not breed until 2 years of age or older (Leitner 
and Leitner 1998, p. 36).
    The Mohave ground squirrel mating season occurs from mid-February 
to mid-March (Harris and Leitner 2004, p. 1). Mohave ground squirrel 
males typically emerge from dormancy in February, up to 2 weeks before 
females (Recht pers. comm., as cited in Gustafson 1993, p. 83). Male 
Mohave ground squirrels defend a territory, which females enter for 
mating (Recht pers. comm., as cited in Gustafson 1993, pp. 83-84). 
Three to four females mate and remain in the male's territory for a day 
or so, before returning to their respective home ranges. After a 
gestation period of 29 to 30 days, the young are born in the female's 
burrow (natal burrow) from March to May, with a peak in April. Average 
litter size is about six (Burt 1936, p. 224; Recht pers. comm., as 
cited by Leitner et al. 1991, p. 63) and ranges from four to nine (Best 
1995, p. 3). Parental care continues through mid-May, with juveniles 
emerging above ground at 10 days to 2 weeks of age (Gustafson 1993, p. 
84). By early May, the juveniles are active above ground and can be 
captured in live traps.
    Reproductive success appears to be strongly influenced by rainfall. 
In dry years, the Mohave ground squirrel's survival strategy appears to 
be to forego reproductive activity and concentrate on gaining weight 
and fat reserves in the spring and early summer to better survive the 
dormant period (Leitner and Leitner 1998, p. 32). For example, Mohave 
ground squirrels in the Coso Range failed to reproduce successfully in 
1989, 1990, and 1994, which correlated with low fall and winter 
precipitation and a low standing crop of annual forbs. In each of the 3 
years, precipitation during the period when it normally occurs in the 
region (September 1 to March 31) was lower than the long-term average 
for the same period (average of 3.3 in (8.5 cm) versus the average of 5 
in (12.7 cm), respectively) (Leitner and Leitner 1998, pp. 18-19, 21, 
and 29). In years when reproduction does occur, females of all age 
classes (including yearlings) produce young (Leitner and Leitner 1998, 
p. 28).
Mortality and Predation
    Mohave ground squirrels can live up to 5 years or longer (Leitner 
and Leitner 1998, p. 28). Mortality for juveniles is high during the 
first year and is disproportionately higher for males than females. As 
a result, the juvenile population contains significantly more females 
than males, and the adult female-to-male ratio averages about 2.6:1, 
but was reported to be as high as 7:1 in one population (Leitner and 
Leitner 1998, p. 36).
    Information on the causes of mortality in the Mohave ground 
squirrel is limited. We are not aware of any information on diseases in 
the species. Although not based on direct observation, predators are 
believed to include coyote (Canis latrans), American badger (Taxidea 
taxus), golden eagle (Aquila chrysaetos), red-tailed hawk (Buteo 
jamaicensis), prairie falcon (Falco mexicanus), common raven (Corvus 
corax), and rattlesnake (Crotalus sp.) (Boarman 1993, p. 2; Gustafson 
1993, p. 88; Harris, pers. comm., as cited in Defenders of Wildlife and 
Stewart 2005, p. 15).
    Mortality may also be caused by extended periods of low amounts of 
winter rainfall, which results in reduced availability of forage and 
water and increases the species' vulnerability to malnutrition, 
disease, and starvation. Gustafson (1993, p. 22) indicated that 
prolonged periods of drought result in the extirpation of Mohave ground 
squirrels in local areas as adult survival is reduced by poor forage 
conditions.
Active Season and Dormancy
    The Mohave ground squirrel lives in burrows which it digs 
(Gustafson 1993, p. ix), and remains in burrows in a state of dormancy 
throughout much of the year. For the Mohave ground squirrel, dormancy 
is a physiological state that includes a reduced frequency of 
breathing, or apnea, reduced oxygen consumption, reduced body 
temperature (Bartholomew and Hudson 1960, pp. 195-197), and a reduced 
heart rate (Ingles 1965, p. 177). Mohave ground squirrels may be active 
from February to August (Bartholomew and Hudson 1960, p. 194), with 
dormancy usually beginning in July or August; emergence dates vary with 
elevation (Johnson no date, p. 1). In years when reproduction occurs, 
most adults are active through June, but all have entered dormancy by 
the end of July; in years with no reproduction, adults may enter 
dormancy as early as the end of April. In contrast, juvenile Mohave 
ground squirrels begin to forage outside their natal burrows by mid-May 
and do not enter dormancy until July at the earliest and as late as the 
end of August (Leitner and Leitner 1998, pp. 32, 38).
    The period when dormancy begins varies annually. Dormancy does not 
appear to be an adaptation to avoid low temperatures; rather it appears 
to be an adaptation to seasonally restricted food and water 
(Bartholomew and Hudson 1960, p. 202). The initiation of dormancy 
appears to correspond to either the absence of available green 
vegetation or its abundance (Aardahl and Roush 1985, pp. 20-21). For 
the latter, the Mohave ground squirrel enters dormancy earlier as food 
abundance allows the animal to meet energy needs to sustain it through 
dormancy earlier (Harris and Leitner 2004, p. 521).
    The principal source of energy for the Mohave ground squirrel 
during dormancy is stored body fat, although food is stored in burrows 
and may be consumed during the dormant period (Ingles 1965, p. 177; 
Recht 1977, p. 85; Johnson no date, p. 1). During more severe drought 
years, Mohave ground squirrels may enter dormancy with relatively low 
body weight, which likely affects survivorship of Mohave ground 
squirrels, especially juveniles, to the following spring (Leitner and 
Leitner 1998, p. 32).
Home Range and Movements
    In general, juvenile Mohave ground squirrels have larger home 
ranges (at least twice as large) than adults, and adult males have 
larger home ranges than females (Aardahl and Roush 1985, p. 11; Best 
1995, p. 6). Mohave ground squirrels are territorial and, throughout 
much of their active period, there is little overlap between home 
ranges (Recht 1977, p. 20). Best (1995, p. 6) observed that home ranges 
are separate until late June, with little evidence of territorial 
behavior. The home ranges are not static and may shift during the 
active season, and from year to year, in response to changes in food 
quality and quantity (Best 1995, p. 6; Harris and Leitner 2004, p. 
520). Home ranges of juveniles form a cluster around the home range of 
an adult (Best 1995, p. 6), and adults exclude juveniles from those 
portions of the habitat with the densest vegetation (Best 1995, p. 6). 
Adult Mohave ground squirrels gain weight twice as fast as most 
juveniles, likely due to differences in resource quality between adult 
and juvenile home ranges (Recht 1977, p. 82).
    Home range size varies with the reproductive period and rainfall 
levels and food availability (Harris and Leitner 2004, p. 1). During 
the mating season, the median male home range is much

[[Page 62221]]

larger than the female home range, 16.6 ac (6.73 ha) compared to 1.8 ac 
(0.74 ha) (Harris and Leitner 2004, pp. 521-522). The females' home 
ranges are non-overlapping and noncontiguous, and each individual 
exhibits a high degree of site fidelity (Harris and Leitner 2004, p. 
522). During the post-mating period, male home range size varies from 
3.7 to 26.7 ac (1.5 to 10.8 ha), while female home range size varies 
from 0.72 to 4.69 ac (0.29 to 1.90 ha) (Harris and Leitner 2004, pp. 
517, 521). Female post-mating home range size is larger than the mating 
season home range (Harris and Leitner 2004, p. 520).
    An evaluation of different sequential survey results indicated that 
juvenile Mohave ground squirrels moved farther than adults (Aardahl and 
Roush 1985, p. 11), and long-distance movements were greater in males 
than in females. Among juveniles, the greatest long-distance movements 
between two sites for males (n = 15) was a mean of 4,987 ft (1,520 m) 
(range 360-20,440 ft (110-6,230 m)), and for females (n = 21) 1,657 ft 
(505 m) (range 344-12,670 ft (105-3,862 m)) (Harris and Leitner 2005, 
p. 188).
    Both adult male and female Mohave ground squirrels vocalize during 
their active season, and have multiple types of calls (Delaney 2009, 
pp. 15-17). The purpose of these calls is unknown but may be linked to 
identifying home ranges.
Habitat Requirements
    The Mohave ground squirrel occurs in a wide variety of habitats in 
the western Mojave Desert (Wessman, as cited in Aardahl and Roush 1985, 
p. 22). They include Mojave creosote bush scrub, Mojave mixed woody 
scrub, desert saltbush scrub, blackbrush scrub, Mojave desert wash 
scrub, Joshua-tree woodland, and shadescale scrub (Gustafson 1993, pp. 
ix, 81; Bureau of Land Management (BLM) 1998, p. 1); Mojave creosote 
bush scrub is the preferred habitat of the Mohave ground squirrel 
(Aardahl and Roush 1985, pp. 22, 23). The Mohave ground squirrel has 
also been found in some areas used for agriculture (Gustafson 1993, pp. 
ix, 81; BLM 1998, p. 1).
    Habitat features considered most suitable for the Mohave ground 
squirrel include areas with relatively flat topography, often located 
in large alluvial-filled valleys, containing fine-to-medium-textured 
soil with little or no rocks, and with the presence of a variety of 
native shrubs, including Larrea tridentata (creosote bush), Ambrosia 
dumosa (white bursage), and Atriplex spp. (saltbush) (Aardahl and Roush 
1985, p. 9).
    Soil characteristics are important, as the Mohave ground squirrel 
constructs burrows to escape temperature and humidity extremes and 
predators, and to give birth (Aardahl and Roush 1985, p. 23). The 
species is absent from very rocky areas and playas (i.e., a sandy, 
salty, or mud-caked flat floor of a desert drainage basin that is 
periodically covered with water) (Wessman 1977, pp. 7-9; Zembal and 
Gall 1980, p. 348). Rainfall must be adequate as it affects the quality 
and quantity of forage (Gustafson 1993, p. 57). Plant species diversity 
and the availability of native annual forbs are important to population 
stability and reproduction (Aardahl and Roush 1985, p. 22). The 
presence of a variety of shrubs that provide a reliable food source 
during drought years may be critical for a population to persist 
(Charis 2005, pp. 3-75).
    The Mohave ground squirrel is considered to be absent, or nearly 
so, from dry lakebeds, lava flows, and steep, rocky slopes, although 
juveniles may disperse through such areas (Leitner, pers. comm., as 
cited in Laabs 1998, p. 3). Harris and Leitner (2005, p. 193) found 
that Mohave ground squirrels travelled through habitats considered 
marginal for permanent occupancy (e.g., contained rocky or gravelly 
soils, and elevation changes of hundreds of feet) but did not cross a 
playa barren of vegetation. Long-distance movement by juveniles through 
marginal areas may be critical for connecting local populations and 
recolonizing sites after local, drought-related extirpations (Harris 
and Leitner 2005, p. 1).

Summary of Information Pertaining to the Five Factors

    Section 4 of the Act (16 U.S.C. 1533) and implementing regulations 
(50 CFR part 424) set forth procedures for adding species to, removing 
species from, or reclassifying species on the Federal Lists of 
Endangered and Threatened Wildlife and Plants. Under section 4(a)(1) of 
the Act, a species may be determined to be endangered or threatened 
based on any of the following five factors:
    (A) The present or threatened destruction, modification, or 
curtailment of its habitat or range;
    (B) Overutilization for commercial, recreational, scientific, or 
educational purposes;
    (C) Disease or predation;
    (D) The inadequacy of existing regulatory mechanisms; or
    (E) Other natural or manmade factors affecting its continued 
existence.
    In making this 12-month finding, information pertaining to the 
Mohave ground squirrel in relation to the five factors provided in 
section 4(a)(1) of the Act is discussed below.
    In making our 12-month finding on a petition to list the Mohave 
ground squirrel, we considered and evaluated the best available 
scientific and commercial information. To ensure that this finding is 
based on the latest scientific information, we contacted species 
experts; land managers within the range of the Mohave ground squirrel; 
the CDFG; and others with expertise on the species, its habitat, and 
threats occurring, or likely to occur, within the range of the species. 
We conducted a search of the available published literature on the 
Mohave ground squirrel and collected unpublished reports on the species 
from resource agencies and others. Unpublished reports included 
regional field studies by State and Federal agencies and conservation 
groups, results of presence/absence surveys conducted prior to proposed 
development, and incidental observations reported by field biologists. 
In addition, we accessed information in the California Natural 
Diversity Database. This information, information provided by the 
public, and additional information and data in our files provided the 
basis for the status review for the Mohave ground squirrel. In making 
our 12-month finding, we considered and evaluated all scientific and 
commercial information in our files, including information received 
during the public comment period that ended June 28, 2010. The analysis 
of potential threats to the Mohave ground squirrel discussed below 
includes those identified in the petition and those identified in the 
information sources listed above.
    In considering what factors might constitute threats to a species, 
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, during the status review, we attempt to determine how significant 
a threat it is. The threat is significant if it drives or contributes 
to the risk of extinction of the species such that the species warrants 
listing as endangered or threatened as those terms are defined in the 
Act. However, the identification of factors that could impact a species 
negatively may not be sufficient to compel a finding that the species 
warrants listing. The information must

[[Page 62222]]

include evidence sufficient to suggest that the potential threat has 
the capacity (i.e., it should be of sufficient magnitude and extent) to 
affect the species' status such that it meets the definition of 
endangered or threatened under the Act.

Factor A: The Present or Threatened Destruction, Modification, or 
Curtailment of the Species' Habitat or Range

    The following potential threats that may affect the habitat or 
range of the Mohave ground squirrel are discussed in this section: (1) 
Urban and rural development, (2) off-highway vehicle (OHV) recreational 
use, (3) transportation infrastructure, (4) military operations, (5) 
energy development, (6) livestock grazing, (7) agriculture, (8) mining, 
and (9) climate change. Climate change is discussed under Factor A 
because, although climate change may affect Mohave ground squirrels 
directly by creating physiological stress, the primary impact of 
climate change on the species is expected to be through changes to the 
availability and distribution of Mohave ground squirrel habitat. In 
addition, commercial filming occurs on private and Bureau of Land 
Management (BLM) lands in the western Mojave Desert. The activities for 
creating motion pictures, television shows, and commercials may require 
travelling on unpaved roads and trails or cross-country use. However, 
in our review of the best available scientific and commercial 
information, we did not find information that indicates these filming 
activities have occurred, are presently occurring, or are likely to 
occur in the future within Mohave ground squirrel habitat, and 
therefore, we have determined that they are not a threat to the 
species.
Urban and Rural Development
    The present and projected future growth of urban areas in the 
western Mojave Desert could adversely affect the Mohave ground 
squirrel. About 136,900 ac (55,426 ha), or 2.6 percent of the 5,319,000 
ac (2,152,532 ha) range of the Mohave ground squirrel (see Background 
section), has been lost to urban and rural development (Defenders of 
Wildlife and Stewart 2005, pp. 19, 38). Loss of Mohave ground squirrel 
habitat has occurred from the construction of residential homes, 
commercial and industrial complexes, shopping malls, golf courses, 
airports and associated commercial and industrial development, roads, 
landfills, wastewater treatment facilities, prisons, flood management 
structures, and other facilities.
    Most urban and rural development has occurred in valleys, flats, 
and gently sloping areas, which are the same types of areas most often 
used by Mohave ground squirrels. The greatest losses of Mohave ground 
squirrel habitat have occurred in, and adjacent to, cities including 
Palmdale, Lancaster, Victorville, Adelanto, Hesperia, Apple Valley, 
Barstow, and Ridgecrest, California (see Map 1). Smaller areas have 
also been lost at the towns of Hinkley, Boron, North Edwards, 
California City, Mojave, Rosamond, Inyokern, and Littlerock, and the 
unincorporated communities of Pearblossom, Phelan, and Pinyon Hills, 
California (see Map 1).
    Most of this urban development has occurred in the southernmost 
portion of the Mohave ground squirrel's range on private land, 
generally south of SR-58 (see Map 1). More than 62 percent of the 
private land within the range of the Mohave ground squirrel is south of 
SR-58. The three cities with the largest developed areas within the 
range of the squirrel (i.e., Lancaster, Palmdale, and Victorville) 
occur in this area, as do several of the smaller towns listed above 
(see Map 1). Some of this area has also been converted to agriculture 
(see ``Agriculture'' section below), and there are areas that do not 
contain suitable habitat for the squirrel (e.g., dry lake beds). We 
estimate the portion of the range of the Mohave ground squirrel south 
of SR-58 to be 1,690,797 ac (684,244 ha), or about 31.8 percent of the 
range of the Mohave ground squirrel (see Background section for our 
range analysis). Urbanization in this area is mainly concentrated along 
the southern edge of the squirrel's range, and much of the area south 
of SR-58 is undeveloped.
    Trapping results in the southern portion of the Mohave ground 
squirrel's range have generally been negative, especially in areas that 
are most heavily developed (Leitner 2008, p. 5). Mohave ground 
squirrels are currently known to occur in several areas south of SR-58, 
including one of the largest concentrations of squirrels on EAFB (see 
below). Recent records of the Mohave ground squirrel south of SR-58 and 
outside EAFB include two in the Victor Valley-Lucerne Valley area 
(Jones pers. comm., as cited in Defenders of Wildlife and Stewart 2005, 
p. 8), four records near Adelanto (Leitner 2008, p. 7), three records 
west and south of Barstow (Leitner 2008, pp. 7-8), and two records 
southwest of the town of Mojave (Leitner 2008, pp. 7-8).
    The fact that trapping results south of SR-58 have generally been 
negative does not necessarily mean that the Mohave ground squirrel is 
absent from the area or the area does not provide habitat for the 
species (Leitner 2008, p. 9). Negative trapping results can occur for 
various reasons, including trap location, time of trapping, and food 
availability (Brooks and Matchett 2002, p. 172; Leitner 2008, p. 9) 
(see ``Range and Distribution'' section and Factor D, ``State Laws and 
Regulations,'' for further discussion of the survey protocol).
    As discussed in the Background section, trapping surveys south of 
SR-58 have most often been conducted in areas where the squirrel has 
already been extirpated due to extensive urbanization, such as the 
Palmdale-Lancaster area in the southwestern portion of the range 
(Leitner 2008, p. 3). More importantly, large areas south of SR-58 have 
either never been surveyed or have been surveyed only 1-2 times 
(Leitner 2008, pp. 5, 9, 25). In addition, the trapping protocol that 
was used may not be the most effective method to determine the presence 
or absence of Mohave ground squirrels. Some scientists have identified 
potential problems with the protocol that raise questions about the 
accuracy of the current survey technique (Brooks and Matchett 2002, p. 
172) (see Factor D, ``State Laws and Regulations,'' for further 
discussion of the survey protocol).
    Federal lands comprise 28.5 percent of the area south of SR-58 (9.3 
percent of the total range of the Mohave ground squirrel). One of the 
more important concentrations of Mohave ground squirrels south of SR-58 
is on EAFB. The 307,435 ac (124,468 ha) EAFB encompasses about 18 
percent of the area south of SR-58 (5.8 percent of the range of the 
Mohave ground squirrel) and contains one of the eight important 
population areas for the Mohave ground squirrel (Leitner 2008, p. 10; 
se Map 2 and Background section). EAFB is used primarily for testing 
and evaluating aircraft, and the impacts to Mohave ground squirrel 
habitat from urban and rural development are primarily confined to the 
small cantonment areas (see ``Military Operations'' section below for 
details).
    In addition to the Federal lands on EAFB, there are more than 
175,000 ac (70,820 ha) of Federal land managed by the BLM south of SR-
58, all of which is not subject to the direct impacts of urbanization. 
These BLM lands include the southern part of the Fremont-Kramer Desert 
Wildlife Management Area (DWMA), which is managed for Mohave ground 
squirrel habitat. Urban and rural development will not occur on these 
lands (however, see ``Off-Highway

[[Page 62223]]

Vehicle Recreational Use,'' ``Military Operations,'' and ``Energy 
Development'' sections below for a discussion on other activities that 
may affect these areas managed by EAFB and the BLM).
    We expect that further urbanization of privately owned lands south 
of SR-58 will occur in the future. The population of the western Mojave 
Desert is projected to grow from 795,000 (in 2000) to more than 1.5 
million people by 2035 (BLM et al. 2005, p. 244). Most incorporated 
cities and communities in the western Mojave Desert have general or 
community plans that describe their growth and development for the next 
20 years or more. We estimate that about 475,000 ac (192,226 ha), or 
about 8.9 percent of the entire range of the Mohave ground squirrel, is 
incorporated. The majority (about 70 percent) of the incorporated land 
south of SR-58 occurs within the cities of Palmdale, Lancaster, 
Victorville, Apple Valley, Hesperia, Adelanto, and Barstow. Although 
these areas are already extensively urbanized, not all of the 
incorporated lands south of SR-58 are developed, and future growth is 
expected to occur in these areas. Under a worst-case scenario, all 
areas within the incorporated boundaries could be developed in the 
future.
    We did not find any information on major proposed urban 
developments or new communities being planned in the unincorporated and 
rural lands south of SR-58, although the existing unincorporated 
communities will likely continue to grow. However, we expect that 
future development will most likely occur in areas that are already 
incorporated because of proximity to existing infrastructure. Although 
we cannot predict with any certainty what areas will be developed or 
when they may be developed in the next 20-30 years, even if all 
incorporated lands south of SR-58 were developed, more than 475,000 ac 
(161,875 ha) would likely remain under Federal ownership south of SR-
58. Much of this land is in the Fremont-Kramer DWMA, which the BLM 
designated for management of Mohave ground squirrel habitat, and 
includes the important population area for the Mohave ground squirrel 
at EAFB (Leitner 2008, p. 10) (see Map 2). Except for possibly minor 
additions to the cantonment areas of EAFB, the Federal land south of 
SR-58 is not subject to urban and rural development.
    About 3,648,830 ac (1,476,635 ha) or 68.6 percent of the range of 
the Mohave ground squirrel is north of SR-58. This area comprises the 
central and northern portions of the range of the Mohave ground 
squirrel. Most of this land has not experienced urban development; 
rather, urbanization is limited and concentrated mainly around 
Ridgecrest and California City. About 144,000 ac (58,275 ha), or 3.9 
percent of the Mohave ground squirrel's range north of SR-58, is 
incorporated, almost all of which (90 percent) is within California 
City (BLM et al. 2005, chapter 3, p. 2). California City was 
incorporated in 1965, and although it is the third largest city in 
California in area, the population has grown to only about 14,120 in 
the 46 years since it was incorporated. Additionally, most of the 
incorporated area remains undeveloped. Given the slow growth rate of 
California City, we believe that much of the land within its 
incorporated boundaries will likely remain undeveloped.
    Federal lands managed by the BLM and Department of Defense (DOD) 
make up about 80 percent (2,109,326 ac (853,617 ha)) of the range of 
the Mohave ground squirrel north of SR-58 (39.7 percent of the entire 
range). The BLM manages 438,364 ac (177, 400 ha), while the DOD manages 
1,670,962 ac (676,217 ha). Most of the 1,110,443-ac (449,382-ha) China 
Lake Naval Air Weapons Station (NAWS) and the 33,359-ac (13,500-ha) 
Goldstone Deep Space Communications Complex (Goldstone Complex), 
managed by the National Aeronautical and Space Administration (NASA), 
experience little habitat disturbance. Seven of the eight Mohave ground 
squirrel important population areas are located north of SR-58, occur 
mostly or entirely on Federal land (see Map 2), and are not subject to 
urban development on Federal land. We do not expect any urbanization to 
occur on BLM land. Because of their missions, we anticipate minimal 
future urban development on the military bases; any development will 
likely be limited to the cantonment areas (see ``Military Operations'' 
section).
    In summary, we recognize that some Mohave ground squirrel habitat 
has been lost to development within the range of the squirrel. 
Currently, about 2.6 percent of the range of the Mohave ground squirrel 
has been lost to development, and we expect that more of the range will 
be lost in the future, most likely adjacent to existing urban areas. A 
worst-case scenario would be that all incorporated land (about 8.9 
percent (475,000 ac (192,226 ha)) within the range of the squirrel is 
developed. Although unlikely because of the expected slow growth of 
California City, even if this were to occur, 62 percent (3,300,000 ac 
(1,335,468 ha)) of the squirrel's range is federally owned, very little 
of which is subject to urban development. We estimate that about 57 
percent of the Federal lands (EAFB, NAWS, Goldstone Complex, DWMAs, and 
Mohave Ground Squirrel Conservation Areas (MGSCA)) are managed, at 
least in part, for Mohave ground squirrel habitat (see Map 2, Table 1, 
and Factor D, ``Federal Laws and Regulations''). The eight important 
population areas for the Mohave ground squirrel occur mostly or 
entirely within Federal lands managed in part for the Mohave ground 
squirrel, and are therefore not threatened with urban development. In 
addition, Leitner (2008, p. 9) has stated that additional populations 
of the Mohave ground squirrel may well exist because much of the range 
of the squirrel has never been surveyed or has only been surveyed 1-2 
times, which may not be sufficient to determine the presence of the 
squirrel (Leitner 2008, p. 25). We conclude, based on this assessment, 
that urban and rural development does not currently pose a threat to 
the Mohave ground squirrel in relation to the present or threatened 
destruction, modification, or curtailment of its habitat or range, nor 
do we anticipate it posing a threat in the future.

  Table 1--Federal Lands Managed for the Mohave Ground Squirrel or Its Habitat, and the Percent of the Species'
                                                    Range \1\
----------------------------------------------------------------------------------------------------------------
                                                                   Percent of Mohave ground squirrel range
                                                           -----------------------------------------------------
                                                                                State/private      Total area
      Management areas for the Mohave ground squirrel            Federal        ownership \2\        within
                                                                ownership          within        management area
                                                                               management area      boundary
----------------------------------------------------------------------------------------------------------------
Mohave Ground Squirrel Conservation Area \3\..............              16.7               7.9              24.6
Department of Defense--Limited Use/Protected..............              27.0                 0              27.0

[[Page 62224]]

 
Bureau of Land Management ACECs \4\ (Fremont-Kramer Desert              13.6               8.5              22.1
 Wildlife Management Area, Superior-Cronese Desert
 Wildlife Management Area, Desert Tortoise Research
 Natural Area) \3\........................................
                                                           -----------------------------------------------------
    Total.................................................              57.3              16.4              73.7
----------------------------------------------------------------------------------------------------------------
\1\ Species' range is 5,319,000 ac (2,152,532 ha) as calculated by the Service.
\2\ State/private ownership is not specifically managed for the Mohave ground squirrel.
\3\ Land ownership within designated boundary includes Federal, State, and privately-owned lands.
\4\ Area of Critical Environmental Concern.

Off-Highway Vehicle Recreational Use
    Off-highway vehicle (OHV) use is any use that includes driving a 
motorized vehicle off a paved road, including driving cross country and 
on existing dirt roads. OHV use has the potential to adversely affect 
the Mohave ground squirrel by crushing individuals (see Factor E, 
``Direct Mortality'') and their burrows (Bury et al. 1977, p. 16), 
damaging or destroying native vegetation, and compacting soils. Burrows 
are essential to the survival of the Mohave ground squirrel, as they 
provide protection from predation and the temperature extremes of the 
desert, are likely used to store food, and provide a safe location for 
reproduction and rearing young. Impacts to vegetation increase the 
exposure of the Mohave ground squirrel to predators, decrease available 
shade for thermoregulation, and increase soil temperature extremes, 
which adversely affect plant germination, growth (Boarman 2002, p. 47), 
and food availability. Compacted soils reduce the infiltration rate of 
rain, which means there is less water available for plants and seed 
germination (Boarman 2002, p. 46), reduce the root growth of 
established plants, and make it harder for seedlings to survive (Lovich 
and Bainbridge 1999, p. 316). With soil compaction, soil erosion from 
wind and water increases, nitrogen fixation is reduced, less organic 
material is available for plant growth, and seedling establishment is 
reduced (Lovich and Bainbridge 1999, pp. 315-316; Boarman 2002, pp. 45-
46).
    OHVs also transport nonnative annual seeds and plant parts from 
other locations. Their roads, trails, and tracks act as dispersal 
corridors for invasive annual plant species (Lovich and Bainbridge 
1999, p. 313). These nonnative species suppress the growth of native 
annual forbs (Brooks 2000, p. 105), which are a source of food and 
water for the Mohave ground squirrel. Many native annual plants have a 
higher percentage of water and protein than nonnative plants (Oftedal 
et al. 2002, p. 344); however, we have no information on the Mohave 
ground squirrel's nutritional needs and their use of nonnative plants.
    Other potential impacts of OHV use include: Noise, which can cause 
hearing loss in rodents (Lovich and Bainbridge 1999, p. 316) and may 
interfere with the Mohave ground squirrel's ability to detect predators 
and establish and maintain territories (Bury et al. 1977, p. 16); 
littering and dumping of garbage (BLM 2003, p. 31), which can attract 
Mohave ground squirrel predators (see Factor C, ``Predation''); and 
increased fire sources (BLM 2003, p. 32), such as campfires and 
cigarettes, which can result in fires that destroy Mohave ground 
squirrel habitat.
    In the western Mojave Desert, the BLM manages its lands for OHV 
recreation. The BLM has designated four open areas (i.e., OHV 
management areas) within the range of the Mohave ground squirrel as 
open to all OHV use, including cross-country use (BLM et al. 2005, 
chapter 3, pp. 242-243). The four OHV management areas within the range 
of the Mohave ground squirrel are: (1) Dove Springs (3,840 ac (1,554 
ha)); (2) El Mirage (25,600 acres (10,360 ha)); (3) Jawbone Canyon 
(3,827 ac (9,642 ha)); and (4) Spangler Hills (62,080 acres (25,123 
ha)) (BLM et al. 2005, chapter 3, pp. 243, 244; Service GIS data) (see 
Map 2). These four areas comprise 95,347 ac (38,586 ha) (BLM 2003, p. 
31), or 1.8 percent of the range of the Mohave ground squirrel. Outside 
of these four areas, the BLM restricts OHV use to specific existing 
roads and trails, and cross-country use is prohibited (BLM et al. 2005, 
chapter 3, pp. 264-273). We are not aware of any plans on the part of 
the BLM to designate new OHV management areas in the future.
    The impacts from OHV use to the Mohave ground squirrel and its 
habitat vary depending on the type of OHV activity, the designated land 
use, and the level of enforcement. The impacts to the Mohave ground 
squirrel and its habitat are greatest in open areas and high-OHV-use 
areas (e.g., staging areas for OHV events, camping areas), and less in 
areas where activities are confined to existing roads and trails.
    Cross-country OHV use is restricted to the four management areas; 
however, the occurrence of off-route OHV use tends to extend or spill 
over into areas immediately adjacent to the management areas. Although 
the impacts to Mohave ground squirrels likely diminish with distance 
from the management areas, the BLM estimates that these ``spill-over'' 
zones, some of which are on private land, encompass an additional 
150,239 ac (60,800 ha) (BLM et al. 2005, chapter 3, pp. 131, 132), or 
2.8 percent of the range of the Mohave ground squirrel. This area, 
combined with the four designated OHV management areas, constitutes 
about 4.6 percent of the range of the Mohave ground squirrel.
    The BLM has documented other areas not associated with the 
designated management areas where OHV use of designated routes is more 
frequent. The BLM estimates that these high-use areas include about 
107,520 ac (43,512 ha), or 2 percent of the range of the Mohave ground 
squirrel (BLM et al. 2005, chapter 3, p. 133). When combined with the 
management areas and spill-over zones, about 6.6 percent of the 
squirrel's range is intensively used for OHV recreation. One of the 
more extensive high-use areas is the Rand Mountains area. To reduce OHV 
impacts in part of the Rand Mountains area, the BLM expanded the 
Western Rand Mountain

[[Page 62225]]

Area of Critical Environmental Concern (ACEC) from 17,877 ac (7,235 ha) 
to 32,050 ac (12,970 ha), and closed the ACEC to OHV use except for 129 
mi (208 km) of designated open routes, a 90-percent reduction in miles 
of open routes (BLM et al. 2005, chapter 3, p. 8). This resulted in a 
reduction of more than 14,000 acres (5,666 ha) of the high-use area in 
the Rand Mountains.
    Although we are not aware of any estimates, the intensive and 
widespread OHV activity that occurs within the management and high-use 
areas has likely resulted in extensive loss and degradation of 
potential habitat for the squirrel. However, the status of the Mohave 
ground squirrel within these areas is not well known. Mohave ground 
squirrels have been trapped in the Dove Springs OHV Area, but not the 
Spangler Hills OHV Area (Leitner 2010, in litt.). Leitner suggests that 
the negative trapping results at the Spangler Hills OHV Area may be 
from an inadequate trapping effort in this large area. Thus, we cannot 
confirm that the Mohave ground squirrel occurs or does not occur at the 
Spangler Hills OHV Area. We are not aware of any information on the 
status of the Mohave ground squirrel in the other two management areas 
or the high-use areas.
    In addition to the management areas and high-use areas, there are 
numerous single unpaved roads and trails within the range of the Mohave 
ground squirrel that are used by OHVs, including utility corridors. The 
potential direct and indirect impacts of roads are described above; 
however, road density and OHV use of these roads are much lower than in 
management areas. This lower use likely means potential impacts to the 
Mohave ground squirrel are less than in management and high-use areas.
    We were unable to find information on the total number of miles of 
unpaved roads within the range of the Mohave ground squirrel. Based on 
a 2001-2002 inventory, the BLM estimated that 5,054 linear mi (8,134 
km) of roads (including paved roads, unpaved roads, and trails) occur 
on BLM land in the western Mojave Desert. However, subsequent to that 
inventory, the BLM permanently closed 2,260 mi (3,637 km), or 45 
percent of the roads and trails (BLM 2003, pp. 4-9). Most closures 
occurred in the DWMAs in Mohave ground squirrel habitat (BLM 2003, p. 
396). DWMAs are ACECs where the BLM can limit or exclude surface 
disturbance, including use of roads and trails (see Factor D). In 
addition, the West Mojave (WEMO) Plan commits the BLM to an aggressive 
program of closed route rehabilitation (BLM et al. 2005, chapter 4, p. 
7). The WEMO Plan is the BLM's resource management plan for the western 
Mojave Desert and amends the California Desert Conservation Area (CDCA) 
Plan. It also implements the Rand Mountains Fremont Valley Management 
Plan that reduces the number of open routes in the Rand Mountains by 90 
percent (BLM et al. 2005, chapter 3, p. 8).
    The BLM has implemented minimization measures to ensure that the 
different types of OHV uses occur within the appropriate designated 
management areas, roads, and trails, and thereby avoid the loss of 
additional Mohave ground squirrel habitat. These measures also allow 
for the eventual restoration of the habitat in areas where the roads 
and trails have been closed to OHV use (although restoration time from 
these impacts is believed to take several decades (Bury et al. 1977, p. 
16; Lovich and Bainbridge 1999, p. 316)). These measures include 
signing closed routes, obscuring closed routes with vertical mulching, 
increasing public education, installing fencing and barriers, and 
increasing law enforcement (BLM et al. 2005, chapter 2, pp. 156-157, 
163). In 2011, BLM is signing open routes, implementing a monitoring 
plan to determine compliance with route closures and whether any new 
illegal routes are being created, and implementing additional 
enforcement capability for the route network in the WEMO Plan area 
(U.S. District Court 2011, pp. 13-15). By 2014, the BLM will be 
preparing a revised OHV route network that complies with the Federal 
Land Policy and Management Act's (FLPMA) requirement to minimize damage 
to public resources and harassment and disruption of wildlife and 
habitat (U.S. District Court 2011, pp. 2, 13). These measures should 
reduce the impacts from OHV use on BLM land near management areas and 
on designated roads and trails in the range of the Mohave ground 
squirrel. However, the BLM's management actions for OHV use only apply 
to lands that they manage; they do not apply to State or private lands.
    Part or all of 14 designated Wilderness areas (BLM et al. 2005, 
chapter 3, p. 9) are in the range of the Mohave ground squirrel. Under 
the Wilderness Act of 1964, roads, new structures, commercial 
activities, and use of motorized vehicles or equipment are prohibited 
within designated wilderness areas (BLM et al. 2005, chapter 3, p. 9). 
The acreage of wilderness area within the range of the Mohave ground 
squirrel and therefore closed to vehicle access and other forms of 
surface disturbance is about 253,000 ac (102,386 ha), or 4.6 percent of 
the range of the Mohave ground squirrel. Although portions of the 
wilderness areas include steep slopes and rocky substrates that would 
not provide suitable habitat for the Mohave ground squirrel, most of 
the wilderness areas are within the elevational range of the Mohave 
ground squirrel (BLM et al. 2005, chapter 3, p. 138) and provide 
connectivity among squirrel habitat.
    DOD lands are closed to public access, and only persons with 
business on the military installations may enter. Because of the 
research, development, testing, and evaluation missions of EAFB and 
NAWS (see ``Military Operations'' below), vehicle access is restricted 
almost entirely to existing roads in those areas (EAFB 2008a, p. 102). 
However, EAFB has designated a 10,387 ac (4,203 ha) OHV recreation area 
on the base for use by base personnel (EAFB 2008a, p. 104), and Fort 
Irwin has an 82 ac (33 ha) OHV recreation area (Department of the Army 
2003, p. 1). Although these activities may impact the Mohave ground 
squirrel and its habitat, the two areas comprise only 0.2 percent of 
the squirrel's range.
    There are no State Vehicular Recreation Areas (SVRAs) in the range 
of the Mohave ground squirrel. SVRAs are operated and managed by the 
Off-Highway Motor Vehicle Recreation Division of California State Parks 
and provide trails, tracks, and other OHV recreational opportunities; 
interpretive and educational activities and publications promoting safe 
and responsible OHV recreation; public safety, including law 
enforcement and first aid; and resource management designed to sustain 
OHV opportunities and protect and enhance wildlife habitat, erosion 
control, revegetation, etc. (California State Parks 2011, unpublished 
information).
    OHV recreation also occurs on private lands. Unauthorized OHV use 
on private lands includes illegal trespass, off-trail riding, illegal 
operation of non-street legal vehicles, and vandalism (Ciani 2011, p. 
1). The Kern County Sheriff's Department is proposing to reduce 
unauthorized OHV use on private lands by expanding and enhancing 
current safety and enforcement efforts (Ciani 2011, p. 1). However, 
there is no information quantifying the degree or extent of the areas 
impacted by this unauthorized use, either in Kern County or anywhere 
else in the range of the Mohave ground squirrel. Additionally, although 
some authorized OHV activity may occur on private lands, we are unaware 
of any information on the degree or extent of

[[Page 62226]]

impacts for authorized OHV activity on private lands.
    OHV recreational use is likely to continue to increase in the 
future. The State's population is projected to grow from 34 million in 
2000 to 46 million by 2020 (BLM et al. 2005, chapter 3, p. 244). The 
demand for OHV recreational opportunities is increasing, along with 
California's growing population (BLM et al. 2005, p. 244). However, the 
BLM has reduced the number of roads and trails available for OHV use 
and has not indicated that it has plans to designate additional OHV 
management or high-use areas in the range of the Mohave ground 
squirrel, and the expected increase in OHV use will mainly be limited 
to existing management or high-use areas.
    In summary, OHV use is a popular recreational activity within 
portions of the range of the Mohave ground squirrel. Potential impacts 
of OHV use vary from none in wilderness areas, to substantial in 
management or high-use areas, depending on the type and intensity of 
OHV activity, the designated land use, and the level of enforcement. 
About 6.6 percent of the range of the Mohave ground squirrel, including 
BLM, DOD, and private lands, is classified as management areas, 
spillover zones, or high-use areas. Although Mohave ground squirrels 
have been reported in one of the four management areas, we have no 
information that indicates that the impacts from OHV use in these areas 
constitute a barrier to their movement. We presume the management areas 
are extensively degraded and provide little value to supporting 
populations of Mohave ground squirrels now or in the future; however, 
these areas occur in less than 7 percent of the range of the Mohave 
ground squirrel. Additionally, we have no information indicating that 
additional management areas will be designated for OHV use in the 
future.
    In addition, the BLM has:
    (1) No plans to designate additional high-use areas or roads and 
trails for the next few decades,
    (2) Closed 45 percent of the roads and trails in the DWMAs and 90 
percent in the western Rand Mountains, and
    (3) Implemented actions to restore habitat in these areas (BLM et 
al. 2005 chapter 2, p. 167) and monitor compliance (such as increasing 
enforcement and minimizing damage to public resources and harassment/
disruption of wildlife and habitat).
    Areas of lesser use, such as existing unpaved roads and trails, can 
result in the loss of habitat, and vehicle activity can crush Mohave 
ground squirrels and their burrows; however, the significance of such 
losses is undocumented for the Mohave ground squirrel. Although miles 
of roads and trails exist, the habitat loss is essentially a narrow, 
linear band, the impacts of which are minor compared to that of a 
management or high-use area. Unpaved roads and trails do not result in 
the total fragmentation of habitat as they are not barriers to Mohave 
ground squirrel movement (Leitner 2010, in litt.).
    OHV use of unpaved roads and trails also occurs on private land, 
and most of this use is probably not authorized by the land owner. 
However, we found no information on the extent of this type of OHV use 
on private lands. At least one county in the range of the Mohave ground 
squirrel has identified unauthorized OHV activities on private land as 
a natural resource and public safety problem and is seeking ways to 
reduce these activities through enforcement (Kern County Sheriff 2011, 
unpublished information).
    Using the best available information, we have determined that OHV 
use is not a significant threat to the Mohave ground squirrel. We found 
no information that the transport and expansion of nonnative vegetation 
or potential impacts of noise and other indirect impacts are adversely 
affecting the Mohave ground squirrel. The impact of OHV use to the 
habitat of the squirrel mainly occurs in management, spill-over, and 
high-use areas, which comprise less than 7 percent of the range of the 
Mohave ground squirrel. Recreational OHV use is of minimal concern on 
DOD land due to restrictions, and because only 0.2 percent of the 
species' range overlaps with DOD recreational use areas. The BLM has 
closed a substantial number of roads and trails in the squirrel's range 
and is implementing measures to monitor and enforce these closures and 
to restore habitat in the closed areas. The BLM has no plans to 
establish additional areas for OHV use in the range of the Mohave 
ground squirrel. Therefore, we find that OHV recreational use on BLM 
land is not a significant threat to the Mohave ground squirrel. 
Although we do not have an exact estimate, less than 2 percent of the 
high-use area is on private land, and one county is pursuing 
enforcement options to address this unauthorized OHV use and its 
impacts on natural resources. In the future, we expect that OHV use 
will likely increase but will be limited to existing management areas 
and designated roads and trails. Therefore, based on our evaluation of 
the best available scientific and commercial data, we conclude that OHV 
recreational use does not currently pose a significant threat to the 
Mohave ground squirrel in relation to the destruction, modification, or 
curtailment of habitat or range, nor do we anticipate OHV recreational 
use posing a threat in the future.
Transportation Infrastructure
    Transportation infrastructure is a network of paved highways and 
roads. Although we were unable to find studies on the effects of 
transportation infrastructure on the Mohave ground squirrel, research 
on other animals has found that the presence of roads in an area may 
have a positive, negative, or no effect on animal abundance (Fahrig and 
Rytwinski 2009, p. 21).
    Potential positive effects of roads include greater availability of 
forage plants adjacent to the roadway caused by precipitation runoff 
from the roadway and fewer predators near roadways because of the 
negative effects of roadways on larger mammals (Garland and Bradley 
1984, p. 47; Fahrig and Rytwinski 2009, p. 21). Potential negative 
impacts from construction and operation may include mortality (see 
Factor E, ``Direct Mortality''), barriers to movement and fragmentation 
(see Factor E, ``Fragmentation''), and habitat loss and degradation 
(Gustafson 1993, pp. 23, 26; BLM 2003, p. 30; Leitner, pers. comm., as 
cited in Defenders of Wildlife and Stewart 2005, p. 22).
    Mohave ground squirrels may be crushed by vehicles, and the 
presence of trash and other animals that are run over by vehicles 
(``road kill'') may attract common ravens and other predators to the 
road and nearby areas, thereby increasing the likelihood that Mohave 
ground squirrels adjacent to these sites would be vulnerable to 
predation (see Factor C, ``Predation''). Some studies showed that roads 
produce an ecological ``road-effect zone,'' a zone over which 
significant ecological effects extend outward from a road (Forman and 
Deblinger 2000, p. 37). Besides road kill and loss of habitat, indirect 
effects of roads in the road-effect zone may include traffic noise, 
which many species avoid, and barriers to movements within a 
population, with potential demographic and genetic consequences (see 
Factor E, ``Fragmentation'').
    Roads alter habitat upslope and downslope by causing hydrologic and 
erosion effects (Foreman and Alexander 1998, p. 217), and promote the 
invasion of nonnative annual plant species (Brooks 2007, p. 154). Thus, 
the road-effect zone may interrupt horizontal ecological flows (e.g., 
animal movements, hydrology), alter landscape spatial patterns (i.e., 
the number, size, and arrangement of ecological pattern

[[Page 62227]]

and ecological function and process), and change species distribution 
and abundance (Forman and Alexander 1998, p. 1). The interruption of 
hydrologic flows may have both positive and negative impacts on the 
habitat of the Mohave ground squirrel. The interruption may provide 
more water to upslope habitat, thereby increasing the amount and 
availability of forage. Conversely, the interruption may impede or 
prevent surface flow from reaching downslope areas, thereby decreasing 
the amount and availability of forage.
    One major highway is planned within the range of the Mohave ground 
squirrel, the High Desert Transportation Corridor. This 63-mi (101.4-
km) long east-west corridor would connect SR-14 in Palmdale with US-395 
(Adelanto) and I-15 (Victorville), and would terminate on the southeast 
side of Apple Valley at SR-18 (see Map 1) (San Bernardino County 2011, 
unpublished information). The corridor would contain a highway with 
all, or portions, composed of freeway/expressway/tollway, and it may 
contain a high-speed rail line (Caltrans 2010a, p. 1). We estimate this 
project would result in the loss of 7,634 ac (3,089 ha), or 0.14 
percent of the range of the Mohave ground squirrel.
    The new highway would be located in the southern portion of the 
range of the Mohave ground squirrel, and south of the important 
population area on EAFB. The highway is planned to include areas 
currently developed for urban and rural use and agriculture, and thus, 
the loss of Mohave ground squirrel habitat would likely be less than 
the footprint of the proposed corridor. The project proponent may be 
required to mitigate for the loss of Mohave ground squirrel habitat as 
part of the permitting process under CESA (Jones 2011, in litt.) (see 
Factor D, ``State Laws and Regulations'') and the WEMO Plan (see Factor 
D, Bureau of Land Management).
    Although the new highway will likely have some effect on the 
habitat of the Mohave ground squirrel beyond what will be removed 
during road construction, we are not aware of any study on the extent 
of a potential road-effect zone or whether such a zone will have a 
positive or negative impact on Mohave ground squirrel populations, or 
how any impacts might change with variables, such as road width, 
traffic rates, and location. The extent of the road-effect zone varies, 
depending on the species being affected, location, habitat, road width, 
traffic density, and other factors. For example, the road-effect zone 
along one road in Massachusetts that passes through an area with many 
swamps and ponds varied from greater than 328 ft (100 m) to greater 
than 3,280 ft (1,000 m), and averaged 1,968 ft (600 m) (Forman and 
Deblinger 2000, p. 1). However, working in the high desert of 
southwestern Utah, which is similar to the environment in the west 
Mojave Desert, Bissonette and Rosa (2009, p. 27) found no clear road-
effect zone for small mammals.
    Although they did not conduct their study in desert areas, Adams 
and Geis (1983, p. 1) found instances where population abundance of 
some small mammal species was greater near roads because of their use 
of the adjacent habitat created or enhanced by the roadway (e.g., water 
collection, increased vegetation). In a creosote bush community in 
southern Nevada, Garland and Bradley (1984, p. 47) found the effects of 
roads on small mammals may differ in deserts when compared with mesic 
habitats. Roadsides receive runoff from pavement, which supports lush 
vegetation compared to adjacent habitat. They also found that round-
tailed ground squirrels, a close relative of the Mohave ground 
squirrel, were more common near roadways (Garland and Bradley 1984, p. 
54). In a review of the literature on the effects of roads on wildlife, 
Fahrig and Rytwinski (2009, p. 3) found that small mammals generally 
showed either a slightly positive effect from roads or no effect.
    With so little known about the effects of roads on the Mohave 
ground squirrel and so many variations in the road-effect zone reported 
in the scientific literature, we employ a worst-case approach to our 
assessment of the impact of the new highway, in which we assume that 
there will be a road-effect zone associated with the new highway and 
that the impacts would be so severe as to eliminate all Mohave ground 
squirrel habitat within the zone. If such a zone were twice or even 
three times the width of the proposed highway, then at most the zone 
would result in the loss of an additional 22,902 ac (9,268 ha) of 
habitat, or an additional 0.43 percent of the range of the squirrel.
    In total, construction of the proposed highway could result in the 
loss of less than 0.6 percent of the range of the Mohave ground 
squirrel, which includes potential impacts associated with a road-
effect zone. However, the actual loss of habitat will likely be less 
because some areas have already been developed and mitigation will 
likely be required for the loss of habitat under the WEMO Plan and CESA 
(see Factor D, Bureau of Land Management and ``State Laws and 
Regulations''). Within the DWMA, the mitigation ratio is 5:1 (see 
``Energy Development'' section below).
    In addition to the proposed highway, two existing highways within 
the range of the squirrel are planned to be modified. Areas of US-395 
may be realigned and portions of SR-58 and US-395 would be widened 
within the range of the Mohave ground squirrel (Caltrans District 8 
website, 2010b, unpublished information). For US-395, the proposed 
widening and realignment projects extend from the southern terminus at 
I-15 north to Kramer Junction (see Map 1). The US-395 projects occur 
within the southern portion of the range of the Mohave ground squirrel, 
well outside any of the important population areas for the squirrel. 
Some of the areas where the road will be widened have already been 
developed (e.g., Adelanto, Victorville, Kramer Junction, etc.) and 
would therefore not result in any additional loss of habitat. However, 
a portion is located in the Fremont-Kramer DWMA, which is managed for 
the Mohave ground squirrel (see Map 2). We estimate the proposed 
highway widening would directly impact an additional 1,600 ac (647 ha), 
or 0.03 percent of the range of the Mohave ground squirrel including 
the areas that have already been developed. If a road-effect zone 
exists for the Mohave ground squirrel, under a worst-case scenario, up 
to an additional 4,800 ac (1,942 ha) of habitat could be lost, or an 
additional 0.09 percent of the range of the squirrel.
    For SR-58, the proposed widening projects extend from near Boron 
east to 7.5 mi (12.1 km) east of Kramer Junction (see Map 1). The 
project would occur in the southern portion of the range of the Mohave 
ground squirrel, well outside any important squirrel population area. 
Most of the proposed highway widening is located in the Fremont-Kramer 
DWMA (see Map 2); however, in the Kramer Junction area, impacts to the 
Mohave ground squirrel have already occurred from existing urban and 
rural development. The proposed highway widening is estimated to 
directly impact an additional 273 ac (110 ha), or less than 0.01 
percent of the range of the Mohave ground squirrel, which includes the 
areas that have already been developed. Again, under a worst-case 
scenario, up to an additional 819 ac (331 ha) could be lost within the 
road-effect zone.
    In total, road widening would result in the loss of about 7,492 ac 
(3,032 ha), or about 0.14 percent of the range of the Mohave ground 
squirrel, which includes potential impacts associated with a road-
effect zone. However, the actual loss of habitat will likely be less 
because some areas have already been developed and mitigation will 
likely be

[[Page 62228]]

required for the loss of habitat under the WEMO Plan and CESA (see 
Factor D, Bureau of Land Management and ``State Laws and 
Regulations''); within the DWMA, the mitigation ratio is 5:1 (see 
``Energy Development'' section below).
    In summary, there are a few major highways and numerous roads 
within the range of the Mohave ground squirrel. There are plans to 
build a new east-west highway across the southern portion of the range 
of the Mohave ground squirrel and widen two existing highways, none of 
which will affect any of the important squirrel population areas. 
Combined, these projects would result in the direct loss of about 9,507 
ac (3,738 ha) of habitat, or about 0.18 percent of the range of the 
squirrel. The actual amount would be less because some areas have 
already been developed and no additional habitat would be lost, and 
mitigation for loss of habitat would be required.
    We acknowledge that roads may affect habitat beyond that lost 
during construction. This road-effect zone can have varying degrees of 
both positive and negative impacts on a species and its habitat, and 
the zone can extend various distances from the road depending on 
factors, such as the species being affected, location, habitat, road 
width, and traffic density. For squirrels and other small mammals, the 
road-effect zone tends to be neutral to slightly positive (Fahrig and 
Rytwinski 2009, p. 13). Although we do not have any information that 
such a zone exists for the Mohave ground squirrel or whether the 
impacts within the zone would be positive or negative, based on a 
worst-case scenario, an additional 28,521 ac (11,542 ha) of habitat or 
about 0.54 percent of the range of the squirrel could be lost. 
Therefore, based on a review of the best available scientific and 
commercial data, we find that transportation infrastructure projects 
likely to occur in the future could affect at most 0.74 percent of the 
range of the Mohave ground squirrel, and therefore do not pose a 
significant threat to the Mohave ground squirrel in relation to the 
destruction, modification, or curtailment of habitat or range. Note 
that other impacts that may be associated with roads, including 
mortality and habitat fragmentation, are discussed under Factor E.
Military Operations
    The DOD manages about one-third of the range of the Mohave ground 
squirrel. Within the species' range, there are three major military 
bases--Fort Irwin and the National Training Center (NTC), EAFB, and 
NAWS.
    Fort Irwin has three major management units; the National Training 
Center (NTC), the Goldstone Deep Space Communications Complex, and the 
Leach Lake Bombing Range. Fort Irwin's primary mission is training 
ground forces for combat, including the use of tanks, other tracked 
vehicles, and wheeled vehicles. Impacts from the training of ground 
forces and associated use of wheeled and tracked vehicles would be 
similar to impacts in OHV management areas (see ``Off-Highway Vehicle 
Recreational Use'' section above). In addition, Fort Irwin has a small 
cantonment area, which contains offices, housing, shops, restaurants, 
utilities, and other facilities. The impacts to the Mohave ground 
squirrel from the cantonment area would be similar to those described 
above under ``Urban and Rural Development,'' but on a very small scale. 
The Army has a proposal for both solar (14,000 ac (5,666 ha)) and wind 
(49 ac (20 ha)) (Department of the Army 2009, p. 33) energy projects 
within the boundaries of Fort Irwin (which also potentially includes 
the Goldstone Complex).
    The NTC is about 642,558 ac (260,035 ha), with approximately 
435,978 ac (176,435 ha) within the range of the Mohave ground squirrel. 
Located on the eastern edge of the range of the Mohave ground squirrel, 
we estimate that 8.2 percent of the range of the species is within the 
NTC boundary, which includes a recent expansion of Fort Irwin's 
southwestern boundary of 75,300 ac (29,745 ha) into an area that is 
within the range of the Mohave ground squirrel (see Factor D, 
Department of Defense, for additional discussion on the expansion 
area). Ground forces training is usually located on the flats and lower 
slopes of the NTC, which are the preferred habitat of the Mohave ground 
squirrel.
    Prior to 1977, the Mohave ground squirrel was not known to occur on 
Fort Irwin. From 1977 to the early 1990s, Fort Irwin conducted surveys 
and found Mohave ground squirrels 40 mi (64 km) farther east than 
previously documented occurrences (Wessman 1977, pp. 11, 12). Krzysik 
(1994, p. 29) documented the impacts of ground forces training on the 
habitat of the Mohave ground squirrel, which included extensive losses 
of shrub cover, soil layers, and cryptobiotic soil crusts. Cryptobiotic 
soil crusts are collections of symbiotic bacteria, algae, fungi, and 
lichen that live on or slightly below the soil's surface and create a 
semipermeable soil surface or crust. They reduce soil erosion, promote 
and control water infiltration, regulate soil temperatures, catch and 
convert atmospheric nitrogen, accumulate organic matter, and facilitate 
native seedling establishment and growth (Boarman 2002, pp. 46 and 47), 
and thus aid in the maintenance of high-quality forage and habitat for 
the squirrel.
    In the future, the 75,300 ac (29,745 ha) expansion area, some of 
which is likely Mohave ground squirrel habitat, will be used for ground 
forces training; impacts to the expansion area are expected to be the 
same as areas currently used for ground forces training. However, the 
entire area within the NTC is not used for ground forces training, as 
some of the terrain is not suitable for training and some areas are set 
aside as buffer zones to shield the training activities from civilian 
uses on lands adjacent to the base's boundary. Human access to the NTC 
is restricted, which precludes the use of the land for other forms of 
surface disturbance (e.g., OHV recreational use, urban and rural 
development, mining). Thus, while some areas are intensively used for 
ground forces training, others are not and remain undisturbed. 
Therefore, the estimated 8.2 percent of the range of the Mohave ground 
squirrel that is within the NTC is an overestimate of the portion of 
the species' range impacted by military training activities. In 
addition, Fort Irwin and the NTC have implemented mitigation measures 
for the Mohave ground squirrel to offset the impacts from the expansion 
area (see Factor D, Department of Defense). The location of the NTC 
does not appear to have an adverse effect on the movement of the Mohave 
ground squirrel between the Coolgardie Mesa and the EAFB important 
population areas (Bell 2006, pp. 43, 72) (see Map 2 and Significant 
Portion of the Range Analysis).
    The 33,359-ac (13,500-ha) Goldstone Deep Space Communications 
Complex, which is operated by the National Aeronautics and Space 
Administration (NASA) for tracking and communication for space 
missions, is off limits to Army training activities, although a tank 
trail constructed in 1985 bisects most of the Complex. Little or no OHV 
use occurs within the Goldstone Complex, because there is no public 
access; personal staff vehicles are confined to paved and dirt 
maintenance roads, and military vehicles are restricted to the tank 
trail. Therefore, the Mohave ground squirrels within the Goldstone 
Complex are essentially protected from military training activities. 
This is 0.6 percent of the range of the Mohave ground squirrel.
    The 91,182 ac (36,900 ha) Leach Lake Bombing Range is managed by 
the Air Force for live-bomb practice, and is off

[[Page 62229]]

limits for ground use because of the high risk of unexploded ordnance. 
This area is 1.7 percent of the range of the Mohave ground squirrel; 
however, only a small portion of it is used for bombing practice. The 
remainder is managed as a buffer from human development in case a bomb 
misses its intended target. Although there are likely patches of Mohave 
ground squirrel habitat in the Bombing Range, their size, spatial 
arrangement, and degree of habitat quality are unknown because there is 
no ground access.
    The 307,435 ac (124,468 ha) EAFB (see Map 1) is primarily used to 
test and evaluate aircraft. Additional activities include conducting 
and supporting tests of aerospace vehicles, evaluating flight and 
recovery of research vehicles, participating in developmental test and 
evaluation programs for the DOD and other government agencies, and 
operating the Air Force Test Pilot School (EAFB 2008b, pp. iii, 19). 
Because the emphasis at EAFB is training and testing in the air, the 
impacts to Mohave ground squirrel habitat are minimal and localized. 
Large areas of the base remain undeveloped and accommodate testing 
activities and buffers for these activities. These undisturbed and 
``off-limits'' areas allow EAFB to conserve natural resources and 
minimize impacts to Mohave ground squirrel habitat.
    Between 1993 and 2007, about 652 ac (264 ha) (about 0.2 percent of 
the base) of permanent land disturbance (e.g., urban development within 
the cantonment area) occurred at EAFB. EAFB recently announced plans to 
construct more than 3,000 ac (1,214 ha) of solar panels in the 
northwestern portion of the base to be energy self-sufficient; however, 
there is no timeframe for this project. Although this project would 
result in the loss of more Mohave ground squirrel habitat than has 
occurred in the past at EAFB (EAFB 2008b, p. iv), it is less than 0.06 
percent of the range of the Mohave ground squirrel and has been sited 
to avoid: (1) The EAFB important population area; (2) areas with 
recorded occurrences of Mohave ground squirrels on EAFB; and (3) areas 
with likely connectivity to the south, east, and north where other 
important populations of Mohave ground squirrel are present (see Map 
2). OHV use is strictly confined to designated areas on the base (see 
``Off-Highway Vehicle Recreational Use'' section), while other 
activities that may affect Mohave ground squirrel habitat (e.g., 
livestock grazing and agriculture) are not allowed (EAFB 2008a, p. 73). 
The southeast portion of the base is designated critical habitat for 
the federally threatened desert tortoise, and the east boundary abuts 
the Fremont-Kramer DWMA, providing connectivity to this and other areas 
managed for the Mohave ground squirrel (see Factor D, Bureau of Land 
Management, and Factor E, ``Fragmentation''). The Air Force has an 
active program on EAFB to minimize ground disturbing activities in 
desert tortoise habitat, which also benefits the Mohave ground squirrel 
(EAFB 2008a, p. 74).
    The Air Force has conducted Mohave ground squirrel presence/absence 
surveys on EAFB since 1988, concentrating on 60 study plots distributed 
throughout the base that were established to monitor long-term trends 
of habitat quality and species diversity (EAFB 2008a, p. 74). Annual 
trapping studies have occurred since the mid-1990s based on funding 
availability (EAFB 2008a, p. 73). Mohave ground squirrels have been 
trapped in all years when trapping was conducted; these results 
indicate that the Mohave ground squirrel is relatively widespread on 
the base except for the northwest portion. Most observations have 
occurred in the east and south portions of EAFB (EAFB 2008a, p. 75). 
Although densities are not available with the methodology used on EAFB, 
one of the Mohave ground squirrel important population areas was 
designated here because the area meets the three criteria for a 
``core'' area (Leitner 2008, p. 12) (see Map 2).
    The 1,110,443 ac (440,695 ha) NAWS is located in the northern 
portion of the range of the Mohave ground squirrel (NAWS 2002, p. 6). 
The primary function of NAWS is to research, develop, test, and 
evaluate weapons systems for Navy, Air Force, Army, Joint Service, 
commercial, and foreign military weapons systems. NAWS also develops 
and tests airborne electronic warfare systems and performs aircraft 
weapons integration (NAWS 2002, p. 1). The Mohave ground squirrel has 
been studied for several years at the Coso Range in the northwest area 
of NAWS (see ``Abundance and Trend'' section) and has been documented 
at other locations throughout the base.
    Impacts to the Mohave ground squirrel and its habitat on NAWS are 
similar to those described for EAFB in both type and magnitude. Similar 
to EAFB, large areas of NAWS remain undeveloped to accommodate aerial 
testing activities and to serve as buffers for testing activities. For 
example, NAWS tests unmanned aerial vehicles for which they need large 
areas of open space to fly these vehicles and test their control 
capabilities and buffers to ensure the safety of civilians outside the 
base. These large undisturbed and ``off-limits'' areas allow NAWS to 
conserve natural resources, including Mohave ground squirrel habitat, 
on much of the base.
    Cattle grazing under BLM grazing leases no longer occurs on the 
base (BLM et al. 2005, chapter 4, p. 98). Feral burros and wild horses 
occur on NAWS. Impacts from burros and horses include loss of annual 
and woody perennial vegetation used by Mohave ground squirrels for 
forage, loss of cover from predators and thermal shade, and soil 
compaction from trailing (NAWS 2002, p. B-97) (see ``Grazing'' section 
below). However, NAWS and the BLM have an extensive burro removal 
program that has substantially reduced the impact of burros (BLM et al. 
2005, chapter 2, p. 81).
    In summary, Mohave ground squirrel habitat has been lost to 
military operations primarily from ground forces training. The largest 
area of loss is in the NTC, including the expansion area, with about 
8.2 percent of the range of the Mohave ground squirrel within the NTC 
boundary. However, the NTC is on the eastern edge of the range of the 
Mohave ground squirrel (see Factor E, ``Fragmentation''), and not all 
of the area within the NTC is impacted by ground forces training. Other 
locations on DOD land, such as the Goldstone Complex and much of EAFB 
and NAWS (more than 1,745,000 ac (706,180 ha)), are undeveloped and 
receive little-to-no surface impacts from military operations. Because 
of military security and the need for large areas of open space to test 
aircraft and weapon systems and buffer areas around the test areas, 
these areas become de facto conservation areas for Mohave ground 
squirrel habitat.
    We found no information that the DOD is proposing to change its 
mission in the future and no information on proposals that would impact 
additional lands within military boundaries. The DOD manages about one 
third of the range of the Mohave ground squirrel. Although about 9 
percent of the range of the squirrel is used for training and testing 
to meet the military's mission, we estimate that 27 percent of the 
range is managed under limited use or de facto habitat conservation for 
the Mohave ground squirrel (see Table 1). Therefore, after reviewing 
the best available scientific and commercial information, we conclude 
that military operations do not currently pose a significant threat to 
the Mohave ground squirrel in relation to the destruction, 
modification, or curtailment of habitat or range of the species, nor do 
we anticipate military operations posing a threat in the future.

[[Page 62230]]

Energy Development
    Energy development includes two components, the power plant where 
energy production or generation occurs, and the transmission line that 
transports the energy to users. In the western Mojave Desert, power 
plants currently generate energy using both non-renewable sources 
(e.g., natural gas, etc.) and renewable sources (e.g., solar, wind, and 
geothermal) with several proposals to generate additional energy using 
renewable sources.
Power Generation
    A total of 22 non-renewable and renewable energy power plants have 
been constructed within or near the range of the Mohave ground 
squirrel, including solar, wind, and geothermal facilities. These 
facilities are located in or near cities and communities in the range 
of the Mohave ground squirrel, including Little Lake, Tehachapi, 
Mojave, Cantil, Argus, Trona, Boron, Hinkley, Hesperia, Victorville, 
Oro Grande, Barstow, Daggett, and Newberry Springs (California Energy 
Commission (CEC) 2011 Web site). These non-renewable and renewable 
power plants produce energy by using water, geothermal, natural gas, 
biomass, wind, solar thermal, and coal, and they have ancillary 
facilities that require ongoing maintenance (such as pipelines, 
transmission lines, and roads). Impacts from the construction and 
operation of these existing facilities to the Mohave ground squirrel 
are similar to those described below for new renewable energy projects.
    In addition, several applications have been submitted to Federal, 
State, and local agencies for the construction and operation of new 
renewable energy projects (e.g., solar, wind, and geothermal) and 
associated transmission lines, and for the expansion of existing 
renewable energy projects in the range of the Mohave ground squirrel.
    Various Federal and State directives foster the increase in 
proposed renewable energy projects. The Energy Policy Act of 2005 
requires the Department of the Interior to approve at least 10,000 
megawatts (MW) of renewable energy on public lands by 2015. The 
American Recovery and Reinvestment Act of 2009 provides monetary 
incentives for utility-level renewable energy development that occurs 
through December 2011. Executive Order 13514 declares the reduction of 
greenhouse gases as a priority for Federal agencies, and Executive 
Order 13212 requires Federal agencies to expedite review of energy 
project applications. In addition, the Governor of California's 
Executive Order S-14-08 requires California electric utilities to 
obtain 33 percent of their power from renewable energy by 2020. These 
laws and directives mean that renewable energy projects will likely be 
located in the Mojave Desert in the future and possibly in the range of 
the Mohave ground squirrel.
    The Department of the Interior has and continues to receive 
applications for utility-scale renewable energy projects on public 
lands, primarily in the western United States. As of November 2010 
(Miller 2010, in litt.), the BLM had received 23 applications for solar 
and wind renewable energy projects in the CDCA, of which part or all of 
each project would be located in the range of the Mohave ground 
squirrel. These applications that are entirely or partly within the 
squirrel's range encompass an estimated 204,200 ac (82,637 ha) of BLM 
land. However, this is only a rough approximation, because at this 
point in the application process we cannot determine with any accuracy 
what areas fall inside or outside the range of the squirrel. Some 
proposed projects are located on both BLM and private land, but the 
amount on private land is not available at this time, and the location, 
size, and status of many of these proposed energy projects changes 
frequently. In addition, it is not likely that all of these proposed 
projects will be permitted (see discussion below under Solar Projects).
    In addition to those applications on BLM-managed lands, several 
applications for solar and wind energy and transmission projects have 
been submitted to other agencies that manage lands in the Mojave Desert 
or that are privately owned. These include the DOD, Department of 
Energy, CEC, California Public Utilities Commission, and County 
planning agencies. At least a portion of many of these projects may 
fall within the range of the Mohave ground squirrel.
    In response to the Federal and State initiatives to encourage 
renewable energy development and the several applications for permits 
for renewable energy projects, the Renewable Energy Action Team (REAT) 
was formed. Its members include the CEC, CDFG, BLM, Service, California 
Public Utilities Commission, California Independent System Operators, 
National Park Service, U.S. Environmental Protection Agency, and DOD. 
The REAT is developing the Desert Renewable Energy Conservation Plan 
(DRECP), which was mandated by California Executive Order S-14-08. This 
plan is a joint State Natural Communities Conservation Plan (NCCP) and 
Federal planning effort that will identify and provide measures 
necessary to conserve and manage natural biological diversity within 
the plan area while allowing compatible and appropriate economic 
development, growth, and other human uses (California Fish and Game 
Code section 2805(g)). This includes mitigation measures that will 
offset impacts to sensitive species that are addressed in the DRECP, 
including the Mohave ground squirrel.

Solar Projects

    Solar energy projects require a large, clear area for placing and 
maintaining photovoltaic panels or mirrors to produce energy and 
ancillary structures, including distribution lines to transport the 
generated energy to a high-voltage transmission line and provide power 
to the administration and operation facilities at the site; pipelines 
to supply water for administration and operation facilities and for the 
production of energy (e.g., washing mirrors and panels, generating 
steam to produce energy); and roads to access the project site, 
distribution line route, and pipeline route(s). Some of these ancillary 
structures are tens of miles long. In addition, some projects are 
obligated to provide energy on cloudy days. Therefore, a backup energy 
system may be constructed within the project site that uses non-
renewable energy sources, such as natural gas or propane, to produce 
energy, which may require the construction of a pipeline to deliver the 
hydrocarbon fuel to the project site.
    Solar energy projects are likely the most destructive renewable 
energy projects to Mohave ground squirrel habitat. Based on the past 
construction and operation of both solar thermal and photovoltaic solar 
energy projects in the Mojave Desert, the footprint of the project site 
is usually a large area, most of which is cleared and maintained free 
of vegetation, and the right-of-way for the transmission line and 
pipeline(s) includes a maintained access road for operation and 
maintenance. Solar energy projects are usually located on level or 
slightly sloping ground, which is characteristic Mohave ground squirrel 
habitat.
    Adverse effects to the Mohave ground squirrel from construction and 
operation of solar plants include crushing animals and their burrows; 
loss of habitat for foraging, cover, and reproduction; increased levels 
of vehicle traffic that potentially result in the increased mortality 
of squirrels and increased predation; introduction of nonnative plants, 
especially along pipelines, transmission lines, and access roads; and 
altering habitat upslope and

[[Page 62231]]

downslope, causing hydrologic and erosion effects.
    There are two existing solar thermal power plants in the range of 
the Mohave ground squirrel, one near Kramer Junction and the second 
near Harper Dry Lake. These two facilities, both of which are located 
on private land, use solar trough or mirror technology, with backup 
natural gas as an energy source to produce power at night and on cloudy 
days. They cover an estimated 3,600 ac (1,457 ha), or 0.07 percent of 
the range of the Mohave ground squirrel, plus additional area for 
transmission lines, pipelines, and access roads. We are unaware of any 
information documenting impacts of these facilities on the Mohave 
ground squirrel population.
    It is difficult to quantify the impacts of proposed solar energy 
projects on the habitat of the Mohave ground squirrel because of the 
uncertainty about their potential number, size, location, and 
jurisdiction. The DOD has proposed the development of 14,000 ac (5,666 
ha) for solar energy production on Fort Irwin and 3,000 ac (1,214 ha) 
on EAFB. Although the average size of a solar project proposed on BLM 
land is about 7,000 ac (2,832 ha), the combined size of the three 
applications BLM has received that fall within the range of the Mohave 
ground squirrel was originally 9,686 ac (3,920 ha) (Miller 2010 in 
litt.). However, one of the three, the 3,883 ac (1,571 ha) Solar 
Millennium project, was recently cancelled after 2 years of 
environmental planning. It should be noted, however, that the 
cancellation of this project does not preclude another project 
proponent from submitting an application for solar development at the 
same site. The sizes of the two remaining projects are substantially 
different (5,325 ac (2,155 ha) versus 478 ac (193 ha)), which adds to 
the uncertainty about potential impacts on Mohave ground squirrel 
habitat. Ultimately, solar energy development on BLM land is likely to 
be limited within the range of the Mohave ground squirrel. Currently, 
none of the proposed solar energy projects are located in any of the 
eight important population areas for the Mohave ground squirrel.
    The BLM is developing programmatic-level guidance for the 
development of solar energy projects and recently released a draft 
programmatic Environmental Impact Statement (EIS) for solar energy (BLM 
and DOE 2010). This draft EIS proposes four solar energy zones (SEZs) 
on 677,400 ac (27,414 ha) in the California desert. These SEZs are 
areas where the BLM would either make processing utility-scale solar 
energy project applications located in SEZs a priority or restrict 
solar energy project development to SEZs. None of the four proposed 
SEZs is in the range of the Mohave ground squirrel, and the EIS 
includes language and a map showing that BLM lands that are ACECs, 
DWMAs, or Mohave ground squirrel habitat are excluded from solar 
development. However, within the range of the Mohave ground squirrel, 
the map identifies scattered tracts of BLM land near the edge of EAFB 
and Victorville that have been identified as available for solar energy 
development (BLM and DOE 2010, p. 2). We note that this is a draft 
document, and the final document may be similar or different from the 
current EIS. Based on the currently available information, none of the 
proposed solar energy projects, the SEZs, or the scattered tracts of 
BLM land are within any of the important population areas for the 
Mohave ground squirrel.
    Under the current WEMO Plan, which may extend to 2035, solar 
development within the range of the Mohave ground squirrel will also be 
restricted because the BLM has a maximum cumulative limit of 1 percent 
new surface disturbance of any kind for the MGSCA. One large solar 
project within the MGSCA would meet or exceed this 1-percent cap on any 
kind of surface disturbance. Although the 1-percent cap also applies to 
DWMAs, solar energy projects on BLM land in DWMAs are not likely to 
occur because of their designation as ACECs (see Factor D, Bureau of 
Land Management). The WEMO Plan also requires a mitigation ratio of 5:1 
for lands within the DWMAs and the MGSCA for habitat lost from ground 
disturbance (BLM et al. 2005, chapter 2, p. 204). The mitigation 
generally involves acquisition of non-Federal land to add to the DWMAs 
and MGSCA, but mitigation measures other than habitat acquisition may 
be implemented to meet the 5:1 mitigation ratio. Outside of these 
areas, the mitigation ratio is 1:1 (BLM et al. 2005, chapter 2, p. 204, 
LaPre 2010). Once the DRECP is completed, the WEMO Plan would likely be 
amended to adopt this plan. The current delineation for the DWMAs and 
MGSCA are not likely to change with implementation of the DRECP.
    BLM does not have jurisdiction over the permitting, development, 
and operation of solar energy projects on private land within the range 
of the Mohave ground squirrel and, therefore, does not have information 
on the number, size, and location of these projects. A project on 
private land may require approval from a County agency only, or from 
the County and the CEC. The applications received by these agencies are 
not always available to the public because of potential competition 
between energy developers, and as with BLM land, the number, size, and 
location of proposed solar energy projects changes frequently. However, 
we are aware of 21 proposed projects on private land within the range 
of the Mohave ground squirrel, which combined total 16,772 ac (6,787 
ha), or about 0.3 percent of the range of the Mohave ground squirrel. 
Many of these projects are proposed for areas that were previously 
cleared and used for agriculture. None of these projects are located in 
any of the important population areas for the Mohave ground squirrel.
    In summary, the impacts from construction and operation of a solar 
project in the range of the Mohave ground squirrel are similar to those 
described in the ``Urban and Rural Development'' section and are 
primarily loss of habitat. Two solar energy projects occur in the range 
of the Mohave ground squirrel, which combined are less than 0.1 percent 
of the range of the Mohave ground squirrel. The solar projects proposed 
on DOD land could comprise about 0.3 percent of the range of the 
squirrel. Three projects have been proposed on BLM land within the 
range of the squirrel, one of which was recently cancelled. The 
remaining two proposed projects make up about 0.1 percent of the range 
of the squirrel. Given the limitations for future development in the 
MGSCA and DWMAs, the BLM's current proposed position to either limit 
utility-scale solar energy development to SEZs or make projects located 
in SEZs a priority for processing over other projects, we expect that 
few solar projects will be approved and constructed on BLM land within 
the range of the Mohave ground squirrel within the foreseeable future.
    We are aware of 21 proposed solar projects on private land, which 
combined are about 0.3 percent of the range of the Mohave ground 
squirrel. However, the locations for many of these projects primarily 
occur on lands previously cleared for agriculture. The combined total 
of existing and proposed solar projects make up no more than 0.81 
percent of the range of the Mohave ground squirrel. It is unlikely that 
all of the proposed projects will be built, and none of them are 
located in any of the important population areas for the Mohave ground 
squirrel. Therefore, based on the best available scientific and 
commercial information, we

[[Page 62232]]

conclude that solar energy development is not currently a significant 
threat to the Mohave ground squirrel in relation to the present or 
threatened destruction, modification, or curtailment of its habitat or 
range, nor do we anticipate it posing a threat in the future.

Wind Projects

    At wind energy project sites, wind turbine towers are scattered 
among hundreds or thousands of acres. The entire project site is not 
cleared of vegetation, rather an area at the base of each tower and the 
roads that provide access to the towers are cleared. Thus, the project 
area is crisscrossed with cleared areas, which are used during 
operation and maintenance. In addition to the roads, ancillary 
facilities include meteorological towers, a substation and an 
electrical collection system of buried electrical cables conveying 
electricity from the wind turbines to a substation, an operation and 
maintenance building, an electrical transmission line and associated 
tower structures to transmit the generated power to an existing high-
voltage transmission line, and a ``switching station'' that connects 
the electrical components associated from the wind turbines to the 
high-voltage transmission line. Additionally, water and sewer lines are 
needed for an operations and maintenance building.
    Adverse effects to the Mohave ground squirrel from construction and 
operation of wind energy projects include crushing animals and their 
burrows; loss of habitat for foraging, cover, and reproduction; 
increased levels of vehicle traffic that potentially result in the 
increased mortality of squirrels and increased predation; introduction 
of nonnative plants, especially along pipelines, transmission lines, 
and roads; and alteration of habitat upslope and downslope causing 
hydrologic and erosion effects. Although wind energy projects are 
usually similar in size or larger than solar energy projects, averaging 
about 8,725 ac (3,530 ha), they do not result in the elimination of all 
habitat within their perimeter as solar energy projects do. Habitat 
remains between the turbine pads and access roads. In addition, unlike 
solar projects, wind energy projects are frequently located on 
ridgelines, slopes, or in passes and would not likely be in areas with 
habitat characteristics preferred by Mohave ground squirrels. However, 
we have no information on how Mohave ground squirrel populations have 
been affected by currently operating wind energy projects or how they 
would be affected by the construction and operation of proposed wind 
energy projects.
    Small patches of wind resources that are considered economically 
feasible to develop occur within the range of the Mohave ground 
squirrel (LM 2005, Appendix B, pp. 31-32), and some wind development is 
likely to occur. However, most of the large, commercially important 
wind fields in the Mojave Desert are to the west and south of the 
squirrel's range. So far, wind energy projects have been constructed on 
non-Federal land along the western edge of the Mohave ground squirrel's 
range in Kern County. Existing projects encompass about 4,900 ac (1,983 
ha) or about 0.01 percent of the range of the Mohave ground squirrel 
(Waln 2011, p. 1). Wind turbines in this area have been placed mainly 
on hilltops and ridgelines, which are not generally suitable habitat 
for the Mohave ground squirrel.
    It is difficult to quantify the impacts of proposed wind energy 
projects on the habitat of the Mohave ground squirrel. Applications 
have been submitted and withdrawn, and the size and location of the 
projects have changed after submission. It should be noted, however, 
that even if a project is cancelled, it does not prevent another 
project proponent from submitting an application for wind development 
at the same site. Recently the demand for energy sources from wind has 
been dampened by a reduction in the price of newly-found sources of 
natural gas and concerns over the future of renewable energy subsidies 
from Congress (Ball 2011, p. 2). As with solar energy projects, there 
is no single entity that is responsible for overseeing the development 
and operation of all wind energy projects in the Mojave Desert or 
within the range of the Mohave ground squirrel.
    There is uncertainty in the development of future wind energy 
projects in the range of the Mohave ground squirrel. For example, only 
one wind project has been proposed on DOD land, a 49 ac (20 ha) project 
on Fort Irwin. In 2010, the BLM reported receiving 20 applications for 
wind energy projects totaling about 194,000 ac (78,509 ha) (Miller 
2010, in litt.), although not all proposals occur within the range of 
the Mohave ground squirrel. The average project size is about 9,700 ac 
(3,925 ha), but sizes range from 160 ac (65 ha) to 45,385 ac (18,367 
ha) (Miller 2010, in litt.). In contrast, in 2011 the BLM's list of 
wind energy applications (BLM 2011a, pp. 1, 3, and 4) did not include 
eight projects from the 2010 list. This change from 2010 was a 
reduction of about 86,000 ac (34,803 ha).
    The total acreage of currently proposed wind energy projects that 
potentially occur in the range of the Mohave ground squirrel is about 
107,347 ac (43,442 ha), or about 2 percent of the range of the species. 
In addition, the actual number of acres that fall within the range of 
the Mohave ground squirrel is likely to be far less because at this 
early stage in the proposal process the boundaries of each project are 
very generalized, and some of the current proposals overlap and some 
are partly outside the squirrel's range. In fact, requests for permits 
submitted to the BLM far exceed the 72,300 ac (29,259 ha) of 
economically developable wind resources that the BLM estimates occur on 
the lands they manage in the entire State of California (BLM 205, pp. 
2-5). Most of the currently proposed wind energy projects on BLM land 
are located along the west and southeast edges of the range of the 
Mohave ground squirrel, and most are located on ridgetops and 
hillsides, which are not considered suitable habitat for the Mohave 
ground squirrel.
    The BLM's wind energy program established policies, Best Management 
Practices (BMPs), and an Instructional Memorandum (IM 2009-043, 
December 19, 2008) to address the administration of wind energy 
development activities and identify minimum requirements for mitigation 
measures. These programmatic policies and BMPs would be applicable to 
all wind energy development projects on BLM lands. Site-specific and 
species-specific concerns, and the development of additional mitigation 
measures, would be addressed in project-level reviews, including 
National Environmental Policy Act (NEPA) analyses, as required (BLM 
2005, Volume 1, Chapter ES, p. 4) (see Factor D below for a discussion 
of NEPA). For example, the BLM recommends establishing a policy by 
which right-of-way grants will not be issued for lands where wind 
energy development would be incompatible with specific resource values 
(BLM 2005, Volume 1, Chapter 2, pp. 6-7), such as those found within 
ACECs. Additional areas of land may be excluded from wind energy 
development on the basis of findings of resource impacts that cannot be 
mitigated and/or conflict with existing and planned multiple use 
activities or land use plans (BLM 2005, Volume 1, Chapter 2, p. 7). 
Other BLM policies include incorporating management goals and 
objectives specific to habitat conservation for species of concern (BLM 
2005, Volume 1, Chapter 2, p. 9), such as the Mohave ground squirrel.

[[Page 62233]]

    Under the current WEMO Plan, which may extend to 2035, wind 
development within the range of the Mohave ground squirrel will also be 
restricted because the BLM has a maximum cumulative limit of 1 percent 
new surface disturbance of any kind for the MGSCA and 1 percent for 
each of the two DWMAs. One large wind project within the MGSCA would 
meet or exceed this 1-percent cap on any kind of surface disturbance. 
The WEMO Plan also requires a mitigation ratio of 5:1 for lands within 
the DWMAs and the MGSCA for habitat lost from ground disturbance (BLM 
et al. 2005, chapter 2, p. 204). The mitigation generally involves 
acquisition of non-Federal land to add to the DWMAs and MGSCA, but 
mitigation measures other than habitat acquisition may be implemented 
to meet the 5:1 mitigation ratio. Outside of these areas, the 
mitigation ratio is 1:1 (BLM et al. 2005, chapter 2, p. 204; LaPre 
2010, in litt.). Although compensation is required, there is no 
requirement that the lands acquired will be enhanced or excluded from 
future development projects, but they are subject to the 1-percent 
development cap. Once the DRECP is completed, the WEMO Plan would 
likely be amended to adopt this plan. The current delineations for the 
DWMAs and MGSCA are not likely to change with implementation of the 
DRECP.
    Although patches of economically developable wind resources occur 
on private land throughout the range of the Mohave ground squirrel, 
most of the proposed and approved projects are along the western edge 
of the Mohave ground squirrel's range in Kern County. The Kern County 
Planning and Community Development Department listed 16 wind projects 
as either approved for construction or as deemed complete to begin the 
approval process (Kern County Planning 2011, pp. 1-2). Thirteen of 
these projects are located partly or entirely within the range of the 
Mohave ground squirrel. Their area is estimated to be 47,000 ac (19,020 
ha), or about 0.9 percent of the range of the Mohave ground squirrel.
    In summary, existing wind energy projects occur in the range of the 
Mohave ground squirrel and additional projects have been proposed and 
approved. Most wind energy projects are or will be located on ridgetops 
and hillsides, which are not considered suitable habitat for the Mohave 
ground squirrel for feeding, breeding, or shelter. None of the existing 
or proposed wind energy projects are located in any of the important 
population areas for the Mohave ground squirrel.
    The impacts from construction and operation of a wind energy 
project in the range of the Mohave ground squirrel would likely be 
similar to those described under the ``Off-Highway Vehicle Recreational 
Use'' section but with low vehicle use due to restricted access, the 
impacts would be reduced.
    Current operational wind energy projects are on non-Federal lands 
on the western edge of the range of the Mohave ground squirrel and 
encompass about 0.01 percent of the species' range. Plans for wind 
energy development on DOD land are limited to 49 ac (20 ha) on Fort 
Irwin. On BLM land, development of wind energy projects in the MGSCA 
would be limited and none is likely to occur in the DWMAs in the future 
as the BLM has imposed restrictions on future development in these 
areas. Although likely an overestimate, if we assume that all proposed 
wind energy projects on BLM land are entirely within the range of the 
Mohave ground squirrel, would be constructed, and would result in the 
total loss of habitat within the project boundaries, 107,347 ac (43,442 
ha), or 2 percent of the range of the Mohave ground squirrel, would be 
lost. On non-Federal land, about 47,000 ac (19,020 ha), or 0.9 percent 
of the range of the Mohave ground squirrel, have proposed or recently 
approved wind energy projects. The combined total of existing, 
proposed, and approved wind projects make up at most about 3 percent of 
the range of the Mohave ground squirrel; however, this is an 
overestimate as the projects would not result in a total loss of Mohave 
ground squirrel habitat.
    Therefore, based on the best available scientific and commercial 
information, we conclude that wind energy development does not 
currently pose a threat to the Mohave ground squirrel in relation to 
the present or threatened destruction, modification, or curtailment of 
its habitat or range, nor do we anticipate it posing a threat in the 
future, because:
    (1) Large areas of economically developable wind resources do not 
occur within the range of the Mohave ground squirrel;
    (2) The number and size of proposed or approved development on DOD 
land is limited;
    (3) There are limitations on the areal extent of development in the 
MGSCA and DWMAs; and
    (4) Typical construction and operation of wind energy projects does 
not result in the total loss of habitat within the project site.

Geothermal Projects

    A typical geothermal project has one or more power plants, a series 
of wells scattered throughout an area, pipelines delivering water to 
the wells and heated water to the power plant(s), a substation, 
transmission lines to a high-voltage transmission line, administrative 
offices, water and sewer lines, and ponds. Geothermal projects are not 
limited to a particular type of terrain as are wind turbines; they may 
or may not be located in areas with suitable habitat for Mohave ground 
squirrels. However, ancillary facilities such as transmission lines, 
pipelines, and access roads, would likely occur in Mohave ground 
squirrel habitat.
    Adverse effects to the Mohave ground squirrel from construction and 
operation of geothermal energy projects include crushing animals and 
their burrows; loss of habitat used for foraging, cover, and 
reproduction; increased levels of vehicle traffic that potentially 
result in the increased mortality of squirrels and increased predation; 
introduction of nonnative plants, especially along pipelines, 
transmission lines, and roads; and altering habitat upslope and 
downslope causing hydrologic and erosion effects. Similar to wind 
energy projects, the overall size of geothermal projects may be large, 
but the entire project area is not cleared of vegetation, which leaves 
patches of habitat within the project area. Habitat patches would 
remain between the wells, pipelines, transmission poles/towers, and 
access roads.
    Unlike solar and wind energy projects, geothermal energy projects 
are restricted to very specific areas where geothermal energy is 
sufficient and near the surface. There are only two locations in the 
range of the Mohave ground squirrel with actual and potential 
geothermal resources (Known Geothermal Resource Areas (KGRA)). One, the 
Coso Hot Springs KGRA, is on both NAWS (NAWS 2002, p. 47) and BLM land 
in the northern portion of the range of the Mohave ground squirrel; the 
second, the Randsburg KGRA, is mostly or entirely on BLM land near 
Randsburg in the central portion of the range of the squirrel (BLM et 
al. 2005, Appendix P-2, p. 3; California Department of Conservation 
2002, p. 1). The single existing geothermal power plant, the Coso 
geothermal plant, is located in the Coso Hot Springs KGRA and consists 
of 106,000 ac (42,897 ha), or 2.0 percent of the range of the Mohave 
ground squirrel. Completed in 1987, it has 4 power plants and more than 
120 wells producing 270 MW of energy (NAWS 2002, p. 48). Within the 
Coso Hot Springs KGRA, the BLM recently approved a 55 ac (22.3 ha) (BLM 
2008, p. 13) project that includes

[[Page 62234]]

a groundwater extraction and pipeline delivery system for injection 
into the existing geothermal project. The addition of the 9-mile-long 
(14.5-km-long) pipeline and access right-of-way would expand the 
existing energy output by pumping an additional 4,800 ac-feet 
(5,920,713 cubic meters) of ground water per year, extending the life 
of the power plants.
    Although a geothermal energy project has been constructed in the 
range of the Mohave ground squirrel, we have no information on how 
Mohave ground squirrel populations have been affected by the currently 
operating project and can therefore only speculate how the Mohave 
ground squirrel would be affected by the construction and operation of 
proposed geothermal energy projects. Mohave ground squirrels at the 
existing project in the northwest portion of the species' range have 
been studied, but the purpose of the study was to gather data on the 
effects of excluding livestock grazing and provide data on the biology 
of the Mohave ground squirrel (Leitner and Leitner 1998, p. i), and not 
the impacts of geothermal development on the squirrel. Only one of the 
important population areas for the Mohave ground squirrel, the Coso 
Range--Olancha area, is near the Coso geothermal power plant. Although 
the power plant is on the southern edge of this important population 
area for the Mohave ground squirrel, it has not been reported as having 
been affected by construction and operation of the geothermal plant.
    The BLM issued a decision on the final programmatic Environmental 
Impact Statement (EIS) for geothermal development in December 2008 (BLM 
and USFS 2008). In its Record of Decision, the BLM determined that 
issuing a geothermal lease does not cause any effect on a species, as 
there is no guarantee that any development will ever take place on such 
a lease (BLM 2008c pp. 1-22). If development does take place, prior to 
the development the BLM would examine individual projects and phases 
(exploration, development, and operation) to determine the appropriate 
level of environmental analysis needed to comply with NEPA (BLM and 
USFS 2008, pp. 2-23) and address the impacts to the Mohave ground 
squirrel at that time. In addition, the BLM would apply stipulations on 
any lease where a special status species, such as the Mohave ground 
squirrel, is known or strongly suspected to occur. These stipulations 
include modifications to existing exploration and development proposals 
or modifications to lease terms (BLM 2008c pp. 1-23). The BLM has 
developed BMPs for geothermal projects which include requiring the 
operator or lessee to identify important, sensitive, or unique habitats 
and biota in the project vicinity, and siting and designing the project 
to avoid (if possible), minimize, or mitigate potential impacts on 
these resources (BLM and USFS 2008, p. D-6), such as the Mohave ground 
squirrel. During each stage from exploration to utilization, the BLM 
retains the authority to approve, deny, or approve with conditions such 
as protective measures (BLM 2008c, pp. 1-24). In the CDCA, geothermal 
leasing is designated for all lands, with the exception of wilderness 
areas (BLM 2008c, pp. 2-3; BLM 1999, p. 15). We are not aware of any 
proposed geothermal projects on private lands in the range of the 
Mohave ground squirrel.
    On September 11, 2009, the BLM issued a notice of intent to prepare 
an EIS for the exploration, development, and use of up to an additional 
22,060 ac (8,927 ha), or 0.4 percent of the range of the Mohave ground 
squirrel in the northern resource area (74 FR 175 46786-46787). Within 
this 22,060 ac (8,927 ha) area, the BLM has received three applications 
for new geothermal development on 4,460 ac (1,805 ha), or 0.08 percent 
of the range of the Mohave ground squirrel. The BLM has received no 
applications for geothermal energy development near Randsburg.
    Once the DRECP is completed, the WEMO Plan would likely be amended 
to adopt this plan. The current delineations for the DWMAs and MGSCA 
are not likely to change with implementation of the DRECP.
    In summary, there are limited locations for geothermal energy 
projects within the range of the Mohave ground squirrel. Currently, 
there is only one operating geothermal energy project in the range of 
the squirrel, and its impacts on the Mohave ground squirrel and its 
habitat have not been studied. Although an important population area 
for the Mohave ground squirrel is nearby the existing project, the 
Mohave ground squirrel has not been reported as having been affected by 
construction and operation of the geothermal plant. Additional 
geothermal energy projects have been proposed in the vicinity of the 
existing plant, and, when added to the existing project, would impact 
about 2.1 percent of the range of the Mohave ground squirrel. However, 
the impacts would likely not affect the entire area, as not all of the 
habitat within these geothermal energy areas is removed during 
construction and operation; not all of the habitat within the project 
sites is likely to be suitable for the Mohave ground squirrel; and the 
BLM is required to implement best management practices to avoid (if 
possible), minimize, or mitigate potential impacts to species of 
concern, such as the Mohave ground squirrel. Therefore, we conclude 
that the construction and operation of geothermal energy projects are 
not currently a threat to the Mohave ground squirrel, nor do we 
anticipate geothermal energy projects posing a threat in the future.
Utility Corridors
    The development of renewable energy projects in the western Mojave 
Desert will require construction of new transmission lines and the 
upgrading of existing transmission lines to carry the increased 
electrical energy production. Pipelines are also needed to carry water 
to some solar and geothermal energy plants for daily operational needs 
and natural gas or propane to some solar energy plants for energy 
production on cloudy days.
    Utility corridors may impact the Mohave ground squirrel and its 
habitat in various ways. Construction activities result in direct 
impacts by crushing Mohave ground squirrels and their burrows, and 
collapsing burrows, which destroy the shelter the species needs to 
escape temperature extremes and predators and to rear young. 
Construction activities also unearth, injure, or kill other animals 
that attract Mohave ground squirrel predators, such as the common 
raven. The construction and use of unpaved roads along transmission 
lines and pipelines affect Mohave ground squirrel habitat in the same 
manner as roads created and used by OHVs (see ``Off-Highway Vehicle 
Recreation Use'' section); OHVs would also use the utility corridors. 
The physical structures (e.g., towers and pads, access roads) cause 
loss of habitat and facilitate predation of the Mohave ground squirrel 
by providing nesting, roosting, and perching habitat for common ravens 
and birds of prey (Boarman and Heinrich 1999, pp. 23-24). Because of 
ongoing operation and maintenance, the recovery or restoration of these 
areas of lost habitat is limited (Lovich and Bainbridge 199, p. 313).
    Because we have no reliable information on the number, size, and 
location of potential renewable energy projects in the range of the 
Mohave ground squirrel, we have no reliable information of the number, 
size, and location of their associated utility lines. However, utility 
corridors in the range of the Mohave ground squirrel already exist, 
having been designated by the BLM. In the range of the Mohave ground 
squirrel, these corridors generally run

[[Page 62235]]

closely parallel to major highways, including I-15, US-395, SR-58, and 
SR-178 (Inyokern to Ridgecrest and Trona). Corridors that are not 
associated with highways, or that are only occasionally associated with 
highways, include ones along the Mojave River, another along the 
southern boundary of Fort Irwin, two north-south corridors in the 
western Antelope Valley, and one east-west corridor near SRs-138 and 18 
(Palmdale to Victorville) (BLM 2011b, p. 1). The purpose for 
designating the corridors is to provide a coordinated and consolidated 
delivery system network that meets the needs of the public and 
minimizes the proliferation of rights-of-way, construction, and loss of 
habitat through the western Mojave Desert (BLM et al. 2005, Chapter 3, 
p. 275). The BLM requires all new linear utilities exceeding certain 
thresholds to be placed within these designated corridors (BLM et al. 
2005, chapter 3, pp. 274-275).
    It is difficult to quantify the impacts of proposed transmission 
lines and pipelines (``lines'') on the habitat of the Mohave ground 
squirrel. First, the number, length, and location of new lines are 
dependent on the size, number, and location of new solar, wind, and 
geothermal development. Applications for these have been submitted and 
withdrawn, and the size and location of some of the projects may have 
changed after they were submitted. The cost of constructing new lines 
is a significant part of the overall cost of an energy project, and 
therefore, most power suppliers locate their power generation source 
close to an existing utility corridor to reduce costs. Regardless, many 
miles of new lines and associated access roads will likely be 
constructed in the range of the Mohave ground squirrel, a portion of 
which will be outside of existing utility corridors.
    Another important factor in determining the overall impact of new 
lines on the Mohave ground squirrel and its habitat is that the BLM 
requires mitigation for the Mohave ground squirrel from direct impacts 
of projects, such as energy development, and utility construction and 
maintenance. The WEMO Plan requires a mitigation ratio of 5:1 for lands 
within the DWMAs and the MGSCA for habitat lost from ground disturbance 
(BLM et al. 2005, chapter 2, p. 204). The mitigation generally involves 
acquisition of non-Federal land to add to the DWMAs and MGSCA, but 
mitigation measures other than habitat acquisition may be implemented 
to meet the 5:1 mitigation ratio. Outside of these areas, the 
compensation requirement is at a rate of 1:1 (BLM et al. 2005, chapter 
2, p. 204, LaPre 2010, in litt.). Although compensation is required, 
there is no requirement that the lands acquired will be enhanced or 
excluded from future development projects, but any acquired lands are 
subject to the 1-percent development cap. Thus, habitat acquisition may 
result in securing blocks of habitat for the Mohave ground squirrel, 
but it will also result in a net loss of total available acres of 
habitat. In addition, the CDFG may require mitigation for the loss of 
Mohave ground squirrel habitat as part of the permitting process under 
CESA (see Factor D, ``State Laws and Regulations'').
    In summary, the construction and operation of utility corridors may 
impact the Mohave ground squirrel through increased animal mortality 
and the loss and degradation of habitat used for feeding, breeding, and 
sheltering. Utility corridors have been designated to minimize the 
proliferation of rights-of-way through the western Mojave Desert and 
range of the Mohave ground squirrel. Many are located along existing 
highways, which confines the locations and impacts of linear structures 
and minimizes new impacts to Mohave ground squirrel habitat. Where 
these rights-of-way cross BLM land, any permitted surface disturbance 
would be limited to a 1 percent development cap in the MGSCA and the 
DWMAs and the mitigation rate would be 5:1. Outside these special 
management areas, the mitigation rate would be 1:1. Thus, habitat for 
the Mohave ground squirrel would likely be lost, but this loss would be 
confined mainly to the utility corridors and other areas of habitat 
would be acquired through mitigation that could benefit the Mohave 
ground squirrel.
Summary of Energy Development
    In summary, 22 non-renewable and renewable energy projects have 
been constructed within the range of the Mohave ground squirrel. No new 
non-renewable projects have been proposed; however, many more renewable 
energy projects have been proposed. Existing solar, wind, and 
geothermal projects encompass about 2.2 percent of the range of the 
Mohave ground squirrel. However, at the present time, there is a great 
deal of uncertainty as to the number, size, and location of future 
energy development and its potential impact on the Mohave ground 
squirrel. This uncertainty is caused by a number of factors, including 
overlapping proposed projects, the cost of supplying renewable energy 
compared to other energy sources, and whether or not the December 2011 
construction deadline for funding under the American Recovery and 
Reinvestment Act of 2009 will be extended.
    Although we are not aware of any studies on the impact of renewable 
energy development on the Mohave ground squirrel, at least some loss of 
habitat will occur, with the potential amount and suitability of the 
habitat lost dependent in part on the type of energy development. Solar 
energy development may occur anywhere there is flat or gently sloping 
land, which is where Mohave ground squirrel habitat usually occurs, and 
is likely the most destructive type of renewable energy to Mohave 
ground squirrel habitat because most of the area is cleared of 
vegetation during construction and operation. In contrast, wind 
development is limited to those areas with economically developable 
wind energy and generally occurs on ridges and hilltops, while 
geothermal development within the range of the Mohave ground squirrel 
is limited to two areas where geothermal energy can be commercially 
developed. The impact of both wind and geothermal development may also 
be less than solar because much of the vegetation is not cleared during 
their construction.
    Future solar and wind development on Federal land, which makes up 
about two-thirds of the range of the Mohave ground squirrel, is likely 
to be limited for several reasons. No solar and wind projects exist on 
the 37 percent of the range of the Mohave ground squirrel that is 
managed by the DOD, while proposed solar and wind development on DOD 
land makes up about 0.3 percent of the range of the Mohave ground 
squirrel. On BLM land, which includes about one-third of the range of 
the Mohave ground squirrel, existing renewable energy projects make up 
about 2.1 percent of the range of the squirrel, most of which is 
geothermal. However, the BLM has received applications for solar, wind, 
and geothermal projects that could encompass about an additional 2.2 
percent of the range of the Mohave ground squirrel. This level of 
development on BLM land is likely an overestimate because the BLM has 
implemented a 1-percent cap (BLM et al. 2005a, chapter 2, p. 48) on all 
new development, including energy projects, in the 1,726,722 ac (698,78 
ha) MGSCA and in the two DWMAs, which total 1,155,835 ac (467,752 ha) 
(BLM et al. 2005, chapter 2, pp. 15, 48, 204) (see Map 2 and Factor D); 
the BLM also requires extensive and potentially expensive mitigation in 
these areas. This cap means the BLM would limit new development in each 
of these areas, which make up most of the range of the

[[Page 62236]]

BLM land within the range of the Mohave ground squirrel, to no more 
than 1 percent under the current WEMO Plan, which may extend to 2035. 
However, the proposed renewable energy projects in these limited 
development areas may already exceed this 1-percent cap, which means 
not all of the proposed projects would be built, and no other permitted 
projects of any kind with surface disturbance could occur in these 
areas.
    For solar development, the BLM has proposed four SEZs in its 
programmatic EIS for solar energy, all of which are outside the range 
of the Mohave ground squirrel and within which solar development is 
more likely to occur. Wind development may be more likely to occur on 
BLM land within the range of the Mohave ground squirrel than solar, but 
it will be restricted because of the 1-percent cap within the MGSCA and 
each of the DWMAs and the required mitigation. The mitigation ratio for 
ground disturbing activities within the MGSCA is 5:1; for land 
acquisition that means up to 65,440 ac (26,483 ha) of private lands 
(inholdings) in the MGSCA could be purchased and become part of the 
MGSCA if the entire 1 percent (13,088 ac (5,297 ha)) was developed. The 
same mitigation requirement (1-percent cap on development and 5:1 
mitigation ratio) applies in the DWMAs, where up to 86,335 ac (34,939 
ha) could be added to the DWMAs. However, assuming the worst-case 
scenario that all proposed wind and geothermal projects on BLM land are 
developed within the range of the Mohave ground squirrel, then as much 
as 2.2 percent of the range would be affected.
    On non-Federal land, which comprises about one-third of the range 
of the Mohave ground squirrel, several solar and wind energy projects 
have been proposed that would impact about 1.2 percent of the range of 
the Mohave ground squirrel. However, many of the projects on private 
land will be constructed on land previously converted to agriculture. 
Therefore, although most probably an overestimate, 5.9 percent of the 
range could be lost as a result of renewable energy development. None 
of the existing or proposed renewable energy projects on Federal or 
private land are located within any of the important population areas 
for the Mohave ground squirrel.
    Renewable energy development will also require the construction of 
additional utility lines, which may result in the loss of Mohave ground 
squirrel habitat. These additional lines will be limited in the MGSCA 
and the DWMAs, as energy development in these areas is expected to be 
limited, long utility lines add substantially to the cost of a project, 
and the lines are subject to the 1-percent development cap and the 5:1 
mitigation ratio. New lines would be subject to a 1:1 mitigation ratio 
outside the MGSCA and DWMAs.
    In conclusion, existing non-renewable energy development has 
occurred in or near cities and communities in the range of the Mohave 
ground squirrel; however, no new non-renewable projects are proposed. 
Renewable energy development has occurred in rural areas within the 
range of the Mohave ground squirrel and has been mainly limited to 
solar thermal development in the central portion of the range and 
geothermal development in the northern portion of the range. Future 
development on Federal land, which makes up about two-thirds of the 
range, is likely to occur outside the MGSCA and the DWMAs. Development 
on BLM land outside the MGSCA and the DWMAs will require a mitigation 
ratio of 1:1. This mitigation could include the acquisition of 
additional lands to be included in the DWMAs and MGSCA. Proposed energy 
development on DOD land makes up 0.3 percent of the range. We are aware 
of several proposed projects on private land, but many of them are in 
areas where the site has been graded, so the habitat is not suitable 
for the Mohave ground squirrel. Therefore, after reviewing the best 
available scientific and commercial information, we conclude that 
energy development does not currently pose a threat to the Mohave 
ground squirrel in relation to the present or threatened destruction, 
modification, or curtailment of its habitat or range, nor do we 
anticipate it posing a threat in the future.
Livestock Grazing
    Potential impacts from livestock grazing to Mohave ground squirrel 
habitat are mainly from degradation of soils and vegetation rather than 
direct loss of habitat, which is limited to construction and use of 
certain livestock improvements, such as livestock troughs, stock tanks, 
and corrals (Lovich and Bainbridge 1999, p. 313). Habitat degradation 
due to grazing occurs to varying degrees and includes soil compaction, 
destruction or degradation of cryptobiotic soil crusts, decreased water 
infiltration, increased erosion, trampling of plants, and overcropping 
(Lovich and Bainbridge 1999, p. 311). Grazing also collapses burrows 
(Boarman 2002, p. 28). Several studies have been conducted that 
document the impacts of livestock grazing, especially overgrazing, on 
soils and vegetation in the Mojave Desert (Busack and Bury 1974, pp. 
181-182; Berry 1978, pp. 511-515; Webb and Stielstra 1979, pp. 522-527; 
Nicholson and Humphreys 1981, pp. 171-81; Brooks 1995, pp. 67-69; Avery 
1998, pp. 67-68).
    In the Mojave Desert, livestock grazing impacts soils in various 
ways. It damages cryptobiotic soil crusts (see ``Military Operations'' 
section) in the open spaces between desert shrubs and causes soil 
compaction. In a comparison of soil conditions following sheep grazing 
in the western Mojave Desert, Webb and Stielstra (1979, pp. 522-523) 
noted that surface strength (a measure of compaction) was significantly 
greater in grazed as compared to ungrazed areas, particularly in the 
upper 4 in (10 cm) of the soil, and that surface erosion was greater 
after grazing.
    Grazing has also been found to reduce the number of seeds in a soil 
seed bank (Brooks 1995, p. 670), which contributes to changes in plant 
communities. In the western Mojave Desert, a study comparing grazed and 
ungrazed plots reported the grazed plot had reduced native forb density 
(Larson et al. 1997, as cited in Boarman 2002, p. 34). Native 
vegetation biomass in the Mojave Desert is higher in areas protected 
from grazing, while nonnative grass biomass is greater outside 
protected areas (Brooks 1995, pp. 67-68).
    The impacts to soils and vegetation in active allotments vary by 
location and intensity. For much of the grazing season, the areas 
livestock graze are limited by distance from water. Grazing intensity 
and associated impacts are generally greater near watering areas, but 
decrease substantially within a short distance (Boarman 2002, p. 34), 
and some areas within an allotment may not be grazed because of their 
distance from water.
    Although several studies have been conducted on the effects of 
livestock grazing on soils and vegetation in the Mojave Desert, we 
found only one study on the effects of livestock grazing on the Mohave 
ground squirrel. This study focused on dietary overlap, not impacts to 
soils and vegetation. Using fecal microhistological analysis, Leitner 
and Leitner (1998, pp. iv, 27) reported that both Mohave ground 
squirrels and livestock rely on the leaves from shrubs, particularly 
one uncommon shrub, Krascheninnikovia lanata (winterfat). This reliance 
by both livestock and squirrels was greater in dry years. The 
researchers concluded there was dietary overlap between the Mohave 
ground squirrel and cattle (Leitner and Leitner 2006, p. 38), but 
provided no information on whether this overlap

[[Page 62237]]

was impacting the Mohave ground squirrel.
    Cattle and sheep grazing are authorized within the range of the 
Mohave ground squirrel. The majority of grazing occurs on BLM land, but 
grazing also occurs on private land. The BLM has designated 21 grazing 
allotments (11 sheep, 7 cattle, and 3 cattle/sheep) within the range of 
the Mohave ground squirrel (BLM et al. 2005, chapter 2, pp. 125, 130; 
chapter 3, pp. 213, 215-216). An allotment is an area designated for 
grazing for a private rancher to use. The grazing program in the WEMO 
Plan addresses BLM lands only; however, many of the BLM allotments 
include both public and private lands (BLM et al. 2005, chapter 2, p. 
130).
    With adoption of the WEMO Plan, the BLM made several changes to 
grazing management. The BLM implemented public land health standards 
and guidelines for grazing management to improve ecological conditions 
and ensure healthy sustainable rangelands (BLM et al. 2005, chapter 2, 
p. 118). The standards in the WEMO Plan include managing soils and 
native species' habitats by managing ecological processes, and include 
indicators to evaluate whether populations and their habitats are 
sufficiently distributed and healthy to prevent the need for listing 
under the ESA (BLM et al. 2005, chapter 2, p. 121). The BLM is required 
to restore, maintain, or enhance habitats of special status species, 
such as the Mohave ground squirrel, to promote their conservation (BLM 
et al. 2005, chapter 2, p. 124).
    Under the WEMO plan, specific management changes to livestock 
grazing in the range of the Mohave ground squirrel included reducing 
the area authorized for grazing in the range of the Mohave ground 
squirrel by 33 percent; eliminating ephemeral grazing for cattle in the 
DWMAs; eliminating sheep grazing in most of the DWMAs; excluding cattle 
grazing in the spring in DWMAs in years when annual plant productivity 
is low; excluding cattle grazing on NAWS; and allowing permittees to 
voluntarily relinquish cattle and sheep allotments (BLM et al. 2005, 
chapter 2, pp. 127, 132-135). These management prescriptions will be in 
effect during implementation of the current WEMO Plan, which may extend 
to 2035. The area currently authorized for grazing by the BLM within 
the range of the Mohave ground squirrel habitat is 1,718,686 ac 
(695,530 ha) of BLM and private land (BLM et al. 2005, chapter 3, pp. 
213, 215-216; Waln 2010, p. 1), or about 32.3 percent of the range of 
the Mohave ground squirrel (see ``Range and Distribution'' section). In 
addition, the BLM reports that although no allotments have been 
voluntarily relinquished, the permittee for the 45,619 ac (38,994 ha) 
Pilot Knob allotment has not grazed livestock recently and has 
requested relinquishment (Fitton 2010, in litt.). This area is 0.9 
percent of the range of the Mohave ground squirrel.
    We do not have any information on regionwide grazing on private 
lands outside of BLM allotments; therefore, the total area grazed 
presented above underestimates the actual area of grazing within the 
range of the Mohave ground squirrel (BLM et al. 2005, Appendix M, no 
page number).
    Mohave ground squirrel habitat can also be degraded by feral burros 
and wild horses, which occur in the northern portion of the species' 
range. Impacts to Mohave ground squirrel habitat from feral burro and 
wild horses are hypothesized to be similar to those of livestock 
grazing. The extent of these impacts on Mohave ground squirrel habitat 
is likely influenced by wild horse and feral burro population density, 
topography and soils, resident plant communities, spatial and temporal 
scale, other disturbances, year to year and longer term climatic 
variation, and animal behavior (Abella 2008, p. 817).
    The BLM has an ongoing program on its lands to capture and move 
feral burros and wild horses (BLM et al. 2005 chapter 2, p. 90), and 
although these animals remain within the range of the Mohave ground 
squirrel, their degree of impact they have on the habitat of the Mohave 
ground squirrel has been greatly reduced. The Navy also has an ongoing 
program to capture and move burros and horses from the NAWS (see 
``Military Operations'' section).
    In summary, although livestock grazing may result in the 
degradation of soils and vegetation, it rarely results in the direct 
loss of habitat, and there is no information that demonstrates 
livestock grazing is negatively impacting Mohave ground squirrel 
habitat. The focus of studies on livestock grazing in the Mojave Desert 
has been on general impacts to soils and vegetation rather than how 
those impacts are affecting the Mohave ground squirrel and its habitat. 
One study found there was dietary overlap between the Mohave ground 
squirrels and livestock for one forage species, but provided no 
information that this was adversely affecting the Mohave ground 
squirrel. Although we are not aware of any significant impacts of 
grazing on Mohave ground squirrel habitat, soil and habitat degradation 
associated with grazing have been further reduced with the BLM's recent 
implementation of public land health standards and guidelines for 
grazing. Recent BLM actions in the range of the Mohave ground squirrel 
include eliminating grazing in some areas and reducing it in others, 
which should improve the condition of the soils and vegetation, 
particularly in the MGSCA and the DWMAs (see Map 2). Over time, these 
changes are likely to provide increased foraging opportunities for the 
Mohave ground squirrel and reduce the overall amount of time that 
livestock spend within these areas, thus reducing impacts to soils, 
vegetation, and dietary overlap. Therefore, based on the best available 
scientific and commercial data, we conclude that livestock grazing does 
not currently pose a threat to the Mohave ground squirrel in relation 
to the present or threatened destruction, modification, or curtailment 
of its habitat or range, nor do we anticipate livestock grazing posing 
a threat in the future.
Agriculture
    Agriculture occurs in the range of the Mohave ground squirrel. 
Agricultural development results in the conversion of native desert 
habitat to croplands and orchards. In addition to the direct loss of 
habitat, agricultural activities expose Mohave ground squirrels and 
nearby habitat to insecticides, herbicides, and rodenticides (Hoyt 
1972, p. 7). Because the Mohave ground squirrel eats both plants and 
insects, it could be adversely affected by the loss or reduction of 
these food items from the use of insecticides and herbicides. In 
addition, drift of insecticides, herbicides, or rodenticides from the 
fields into adjacent habitat or bioaccumulation of these chemicals from 
contaminated forage and insects could adversely affect the Mohave 
ground squirrel.
    We found no information that the use of pesticides is adversely 
affecting the Mohave ground squirrel from direct exposure, reduction of 
forage, or bioaccumulation from consuming treated vegetation or 
insects. Habitat loss from agricultural activities has occurred at 
several locations within the range of the Mohave ground squirrel. By 
the early 1990s, more than 39,000 ac (15,700 ha), or 0.7 percent of the 
range of the Mohave ground squirrel, had been lost to agriculture, 
including areas in the Antelope Valley and Mojave River Basin 
(Gustafson 1993, p. 24). In 1994, Krzysik (1994, p. 18) reported that 
the spread of alfalfa fields throughout the species' southern range in 
the Mojave River area had destroyed prime Mohave ground squirrel 
habitat and fragmented populations. Krzysik (1994, p. 18) concluded 
that the Mohave ground squirrel was no longer found in the

[[Page 62238]]

Lucerne Valley, Apple Valley, or Victorville areas, which are in the 
southern portion of the squirrel's range (see Map 1). We estimate this 
area to be about 2.4 percent of the range of the Mohave ground 
squirrel. However, there have been recent sightings of the Mohave 
ground squirrel near Adelanto and Hesperia (Victorville/Mojave River 
Valley area) and Mojave (western Antelope Valley) (Leitner 2008, pp. 6-
7) (see Map 1).
    We acknowledge that past agricultural development resulted in the 
destruction of Mohave ground squirrel habitat. However, the current 
cost of pumping ground water to irrigate crops in the western Mojave 
Desert discourages the development of new areas for agriculture (Los 
Angeles County Cooperative Extension 2009, p. 1). In addition, many 
areas historically used for agriculture are being converted to 
residential and commercial development (Los Angeles County Cooperative 
Extension 2009, p. 1). This conversion would not result in additional 
loss of habitat for the Mohave ground squirrel, as the native 
vegetation had previously been removed when developed for agriculture. 
After reviewing the information on Web sites of local agricultural 
agencies in the western Mojave Desert, we conclude that there will 
likely be no increase in agricultural development in the future. Given 
the best available scientific and commercial data, and the small 
percent of the range of the species affected by agriculture, we 
conclude that agriculture does not currently pose a threat to the 
Mohave ground squirrel in relation to the present or threatened 
destruction, modification, or curtailment of its habitat or range, nor 
do we anticipate it posing a threat in the future.
Mining
    Limited mining occurs in the range of the Mohave ground squirrel, 
and includes mineral, sand, and gravel mines. Mining results in the 
loss of Mohave ground squirrel habitat through removal of vegetation 
used for forage and cover, and removal of soils used for burrows, which 
provide protection from temperature extremes and predation, and serve 
as a location to give birth. Travel off road during mining exploration, 
and the construction and use of roads to access the mine site during 
production, also result in the loss of habitat (Boarman 2002, p. 18). 
These activities impact the Mohave ground squirrel by damaging and 
removing shrub cover and compacting the soil (see ``Off-Highway Vehicle 
Recreational Use'' section above for additional details). Extracting 
minerals is usually done by constructing addits (a type of horizontal 
shaft), shafts, and/or pits. The unused materials may include 
overburden, waste ore, and tailings, which are deposited near the mine 
site. A mining operation may require office space, storage facilities, 
and power plants at the mine site. These activities impact Mohave 
ground squirrels through a direct loss of habitat, similar to impacts 
from urban development, although on a reduced scale (Boarman 2002, p. 
18) (see ``Urban and Rural Development'' section).
    Mining has occurred in the western Mojave Desert for more than a 
century. Minerals extracted in the western Mojave Desert include gold, 
borates, and aggregate materials (sand, gravel, and stone). Mine size 
ranges from less than a few acres for recreational mining and 
exploration, to large commercial mines covering several square miles. 
However, most of the mines in the western Mojave Desert are small and 
their impacts are very limited and localized.
    The only extensive mining operation in the range of the Mohave 
ground squirrel is the U.S. Borax borate mine located north of Boron 
(see Map 1). This operation is proposing to increase its footprint by 
1,500 ac (607 ha) (U.S. Borax 2008, Figure ES-2), which would allow the 
mine to operate past 2050. Sand, gravel, cement, and other mineral 
commodities used for construction materials are in demand as the 
population in the western Mojave Desert and southern California 
continues to grow. We anticipate there will be an increase in demand 
for these materials in the future in the western Mojave Desert (BLM et 
al. 2005, Appendix P, p. 2), despite the current slowdown in the 
economy. As sand and gravel mining operations deplete their material 
sources at currently approved mining sites, they will likely request 
permits to expand their current operation sites (e.g., Ag Con in Oro 
Grande, San Bernardino County 2003 Mining Conditional Use Permit and 
Reclamation Plan). Mine expansion would result in the loss of Mohave 
ground squirrel habitat, but this loss would likely be minimal in area 
when compared to the range of the species (far less than 0.01 percent 
of the range). Much smaller existing or proposed gold and silver mines 
are in the Mojave-Rosamond and Randsburg areas, but these mines are 
located on rocky buttes and do not occur in Mohave ground squirrel 
habitat.
    Commercial and recreational mining does not occur on DOD lands. On 
public land, the BLM allows mining in all areas, unless the land has 
been withdrawn from mineral entry. Lands not withdrawn but requiring an 
approved plan of operation prior to commencing mining activities 
include proposals to remove more than 1,000 tons of ore, to disturb 
more than 5 ac (2 ha) of BLM land, or to be located on lands that are 
ACECs or wilderness. Class L public lands are limited-use areas to help 
protect sensitive, natural, scenic, ecological, and cultural resource 
values. These public lands are also managed to provide for generally 
lower-intensity, carefully controlled multiple use of resources, while 
ensuring that sensitive values are not significantly diminished. Class 
C public lands are wilderness areas with controlled use that is also 
closed to OHV use (BLM et al. 2005, chapter 3, p. 3 and Appendix P, p. 
4). Casual mining use or prospecting can occur on BLM lands in the 
western Mojave Desert, as can commercial mining. However, the DWMAs are 
ACECs and the MGSCA area is Class L land. The BLM would need to approve 
a plan of operation prior to anyone initiating mining activities in 
these areas. The plan of operation would also need to include the 5:1 
mitigation ratio, and mine development would contribute to the 1-
percent development cap. Given these requirements, it is unlikely that 
mining would occur on these lands in the range of the Mohave ground 
squirrel in the future.
    In summary, mining occurs in the range of the Mohave ground 
squirrel on private and BLM lands. However, using the best available 
scientific and commercial information, we find that only a small number 
of known active and proposed mines occur in the range of the Mohave 
ground squirrel; many of these mines are located in areas that are not 
suitable habitat (i.e., rocky, mountainous areas) for the Mohave ground 
squirrel; and commercial mining is absent on DOD lands (which 
constitute about one third of the range of the species). Therefore, we 
conclude that mining does not currently pose a threat to the Mohave 
ground squirrel in relation to the present or threatened destruction, 
modification, or curtailment of its habitat or range, nor do we 
anticipate it posing a threat in the future.
Climate Change
    Climate change may be impacting the Mohave ground squirrel. Climate 
change is discussed here under Factor A because, although climate 
change may affect the Mohave ground squirrel directly by creating 
physiological stress, the primary impact of climate change on the 
Mohave ground squirrel is expected

[[Page 62239]]

to be through changes to the availability and distribution of Mohave 
ground squirrel habitat.
    ``Climate'' refers to an area's long-term average weather 
statistics (typically for at least 20- or 30-year periods), including 
the mean and variation of surface variables, such as temperature, 
precipitation, and wind, whereas ``climate change'' refers to a change 
in the mean and/or variability of climate properties that persists for 
an extended period (typically decades or longer), whether due to 
natural processes or human activity (Intergovernmental Panel on Climate 
Change (IPCC) 2007a, p. 78). Although changes in climate occur 
continuously over geological time, changes are now occurring at an 
accelerated rate. For example, at continental, regional and ocean basin 
scales, recent observed changes in long-term trends include: A 
substantial increase in precipitation in eastern parts of North America 
and South America, northern Europe, and northern and central Asia, and 
an increase in intense tropical cyclone activity in the North Atlantic 
since about 1970 (IPCC 2007a, p. 30); and an increase in annual average 
temperature of more than 2 degrees Fahrenheit (F) (1.1 degrees Celsius 
(C)) across the U.S. since 1960 (Global Climate Change Impacts in the 
United States (GCCIUS) 2009, p. 27). Examples of observed changes in 
the physical environment include: An increase in global average sea 
level, and declines in mountain glaciers and average snow cover in both 
the northern and southern hemispheres (IPCC 2007a, p. 30); substantial 
and accelerating reductions in Arctic sea ice (e.g., Comiso et al. 
2008, p. 1), and a variety of changes in ecosystem processes, the 
distribution of species, and the timing of seasonal events (e.g., 
GCCIUS 2009, pp. 79-88).
    The IPCC used Atmosphere-Ocean General Circulation Models and 
various greenhouse gas emissions scenarios to make projections of 
climate change globally and for broad regions through the 21st century 
(Meehl et al. 2007, p. 753; Randall et al. 2007, pp. 596-599), and 
reported these projections using a framework for characterizing 
certainty (Solomon et al. 2007, pp. 22-23). Examples include: (1) It is 
virtually certain there will be warmer and more frequent hot days and 
nights over most of the earth's land areas; (2) it is very likely there 
will be increased frequency of warm spells and heat waves over most 
land areas, and the frequency of heavy precipitation events will 
increase over most areas; and (3) it is likely that increases will 
occur in the incidence of extreme high sea level (excludes tsunamis), 
intense tropical cyclone activity, and the area affected by droughts 
(IPCC 2007b, p. 8, Table SPM.2). More recent analyses using a different 
global model and comparing other emissions scenarios resulted in 
similar projections of global temperature change across the different 
approaches (Prinn et al. 2011, pp. 527, 529).
    All models (not just those involving climate change) have some 
uncertainty associated with projections due to assumptions used, data 
available, and features of the models; with regard to climate change 
this includes factors such as assumptions related to emissions 
scenarios, internal climate variability and differences among models. 
Despite this, however, under all global models and emissions scenarios, 
the overall projected trajectory of surface air temperature is one of 
increased warming compared to current conditions (Meehl et al. 2007, p. 
762; Prinn et al. 2011, p. 527). Climate models, emissions scenarios, 
and associated assumptions, data, and analytical techniques will 
continue to be refined, as will interpretations of projections, as more 
information becomes available. For instance, some changes in conditions 
are occurring more rapidly than initially projected, such as melting of 
Arctic sea ice (Comiso et al. 2008, p. 1; Polyak et al. 2010, p. 1797), 
and since 2000 the observed emissions of greenhouse gases, which are a 
key influence on climate change, have been occurring at the middle to 
higher levels of the various emissions scenarios developed in the late 
1990s and used by the IPPC for making projections (e.g., Raupach et al. 
2007, Figure 1, p. 10289; Manning et al. 2010, Figure 1, p. 377; Pielke 
et al. 2008, entire). Also, the best scientific and commercial data 
available indicate that average global surface air temperature is 
increasing and several climate-related changes are occurring and will 
continue for many decades even if emissions are stabilized soon (e.g. 
Meehl et al. 2007, pp. 822-829; Church et al. 2010, pp. 411-412; 
Gillett et al. 2011, entire).
    Changes in climate can have a variety of direct and indirect 
impacts on species, and can exacerbate the effects of other threats. 
Rather than assessing ``climate change'' as a single threat in and of 
itself, we examine the potential consequences to species and their 
habitats that arise from changes in environmental conditions associated 
with various aspects of climate change. For example, climate-related 
changes to habitats, predator-prey relationships, disease and disease 
vectors, or conditions that exceed the physiological tolerances of a 
species, occurring individually or in combination, may affect the 
status of a species. Vulnerability to climate change impacts is a 
function of sensitivity to those changes, exposure to those changes, 
and adaptive capacity (IPCC 2007, p. 89; Glick et al 2011, pp. 19-22). 
As described above, in evaluating the status of a species, the Service 
uses the best scientific and commercial data available, and this 
includes consideration of direct and indirect effects of climate 
change. As is the case with all potential threats, if a species is 
currently affected or is expected to be affected by one or more 
climate-related impacts, this does not necessarily mean the species is 
a threatened or endangered species as defined under the Act. If a 
species is listed as threatened or endangered, this knowledge regarding 
its vulnerability to, and impacts from, climate-associated changes in 
environmental conditions can be used to help devise appropriate 
strategies for its recovery.
    While projections from global climate model simulations are 
informative and in some cases are the only or the best scientific 
information available, various downscaling methods are being used to 
provide higher resolution projections that are more relevant to the 
spatial scales used to assess impacts to a given species (see Glick et 
al. 2011, pp. 58-61). With regard to the area of analysis for the 
Mohave ground squirrel, downscaled projections are available to some 
degree. Specifically, the IPCC models predict that precipitation will 
decrease, but the frequency and magnitude of extreme precipitation 
events will increase. The IPCC provides a more recent report that 
supports EPA's prediction of temperature increases and adds that rising 
air and ocean temperature is unquestionable (IPCC 2007a, p. 4). The 
Western Regional Climate Center's California Climate Tracker has 
developed 11 climate-monitoring regions for California. The western 
Mojave Desert is part of one region that includes most of the Mojave 
Desert in California and the Owens Valley. Data collected from this 
region indicate that mean, maximum, and minimum temperatures have 
increased during the last 110 years (Redmond 2009, pp. 36-46).
    There is still a considerable degree of uncertainty associated with 
projecting future climate change, due in part to uncertainties about 
future emissions of greenhouse gases and to differences among climate 
models and simulations (Stainforth et al. 2005, pp. 403-406; Duffy et 
al. 2006, pp. 873-874), and to the inability to predict change at a 
local scale. It is difficult with currently

[[Page 62240]]

available models to make meaningful predictions of climate change for 
areas such as the range of the Mohave ground squirrel (Parmesan and 
Matthews 2005, p. 354). The difficulty in predicting how an animal or 
plant will respond further increases the uncertainty of evaluating the 
potential impacts of climate change. Responses may include changes in 
distribution, population size, behavior, and physiological and physical 
characteristics (Parmesan and Mathews 2005, p. 373). Several published 
studies predict that temperature and precipitation trends may change in 
the near future, and some describe how biotic communities may respond 
to such changes (Parmesan and Mathews 2005, pp. 333-374; IPCC 2007a, 
pp. 1-21; IPCC 2007b, pp. 1-22; Jetz et al. 2007, pp. 1211-1216; Kelly 
and Goulden 2008, pp. 11823-11826; Loarie et al. 2008, pp. 1-10; Miller 
et al. 2008, pp. 1-17). In the interior western region of the United 
States, species may respond to increases in temperature by shifting 
their range to cooler areas.
    The Mohave ground squirrel usually occurs in the flats and alluvial 
fans between rocky, mountainous areas. Based on the specific known 
habitat requirements of the Mohave ground squirrel, the species could 
respond to ambient temperature increases in three general ways: (1) 
Constrict its range; (2) move farther north; or (3) move higher in 
elevation within its current range. Moving farther north would require 
travelling over rocky hills, which is difficult, but possible, in some 
areas for the Mohave ground squirrel (see ``Home Range and Movements'' 
section). Moving to higher elevations would require the Mohave ground 
squirrel to cross rocky terrain and inhabit more marginal habitats at 
higher elevations with less suitable substrate for burrow construction. 
The most likely response by the Mohave ground squirrel to climate 
change would be to move north. However, we cannot be certain that the 
Mohave ground squirrel will respond this way. Regardless of the 
species' response to ambient temperature increases, ultimately the 
range of the species will likely be smaller than it is currently.
    Based on the information discussed above, we acknowledge that 
temperatures in the western Mojave Desert where the Mohave ground 
squirrel occurs have increased and are likely to continue increasing. 
We also acknowledge that, if hotter and drier summers and more extreme 
weather patterns in temperature and precipitation occur within its 
range, the Mohave ground squirrel may be negatively affected. As 
discussed in the ``Biology and Natural History'' section, the activity 
period of the Mohave ground squirrel is generally spring and early 
summer when they mate and forage to sustain themselves for the 
remainder of the year. Increased temperatures could cause Mohave ground 
squirrels to have a shorter active period. A reduced active period may 
lessen the species' ability to consume and store sufficient forage to 
sustain it through the dormant period, and may reduce the frequency of 
reproduction. If precipitation declines, the availability of nutritious 
forage would likely decline in a given year and across years. If such 
reduced precipitation levels persist, the habitat may no longer be 
suitable for the Mohave ground squirrel during the drought period.
    Drought is a natural feature of the Mojave Desert. The State of 
California has experienced cycles of drought for many years. For 
example, between 1928 and 1987 the U.S. Geological Survey (USGS) 
reported five severe droughts across California, including the longest 
drought in the State's history during the period 1929-1934 (USGS 2004, 
p. 2).
    The Mohave ground squirrel has evolved several adaptations to 
persist in an environment with drought. These adaptations include 
suppressing reproduction during periods of low rainfall and food 
availability, retreating to burrows for most of the year to escape 
temperature and humidity extremes in summer and winter, reducing 
physiological demands by going into a state of torpor for much of the 
year, and caching food in burrows. However, prolonged drought 
exacerbates the effects of drought on the species; no young may be born 
for several years, the survivability of adults is reduced by poor 
forage conditions, and the surviving adults eventually die due to old 
age or predation (Gustafson 1993, p. 22). This situation can result in 
the extirpation of the Mohave ground squirrel in local areas (Gustafson 
1993, p. 22). However, based on past records of severe drought, the 
Mohave ground squirrel has demonstrated that it can persist and 
recolonize areas following episodes of severe drought. Therefore, we 
have no information that supports the assumption that severe drought 
will threaten the species in the foreseeable future.
    We also have no information on which to base meaningful predictions 
on how climate change may influence the duration or severity of drought 
within the range of the Mohave ground squirrel, or how its status may 
be affected. Increasing temperature could result in more severe and 
frequent drought, especially in the Southwest (Karl et al. 2009, p. 
42). However, we are not aware of any formal studies on the direct 
effect of rising global temperature on drought severity or frequency 
(Karl et al. 2009, p. 5). Drought severity and frequency are a function 
of a complex series of factors, such as the El-Nino-Southern 
Oscillation (ENSO) intensity and duration, as well as geographic 
variations in sea surface temperature, which may also be affected by 
increasing temperatures (Karl et al. 2009, p. 105), thereby compounding 
the uncertainty associated with precipitation projections (Karl et al. 
2009, p. 105).
    In summary, within the range of the Mohave ground squirrel, the 
potential effects of climate change, their magnitude, and projections 
on how the species will react are speculative for several reasons, 
including the uncertainties of climate projection models, the lack of 
models for projecting climate change for relatively small geographic 
areas, the complexity of interacting factors that may influence 
vegetation changes, and the uncertainty regarding the effects of 
climate change on the Mohave ground squirrel's foraging, breeding, and 
movement/dispersal behaviors. Although climate change may have some 
effect on the species, at this time we cannot make meaningful 
projections on either how the climate within the range of the Mohave 
ground squirrel may change, or how the species may react to climate 
change. The Mohave ground squirrel has survived several periods of 
drought in the 20th century, including a 5-year drought in the early 
20th century, and has evolved several adaptations to persist in an 
environment with drought as a natural feature of its environment, 
including recolonizing areas following episodes of severe drought. 
Therefore, based on a review of the best available scientific and 
commercial data, we conclude that climate change does not currently 
pose a threat to the Mohave ground squirrel in relation to the present 
or threatened destruction, modification, or curtailment of its habitat 
or range, nor do we anticipate it posing a threat in the future.
Summary of Factor A
    We have assessed the best available scientific and commercial data 
on the impacts of urban and rural development, OHV recreational use, 
transportation infrastructure, military operations, energy development, 
livestock grazing, agriculture, mining, and climate change on the range 
and habitat of the Mohave ground squirrel.
    Urban and rural development destroys habitat used by the Mohave

[[Page 62241]]

ground squirrel for feeding, breeding, and shelter; reduces or prevents 
movement of individuals among populations (see Factor E); and 
introduces human behaviors that result in an increase in the number of 
Mohave ground squirrel predators (see Factor C). Most habitat loss 
occurs at the southern end of the species' range in the incorporated 
areas of Palmdale, Lancaster, Victorville, Apple Valley, Hesperia, 
Adelanto, and Barstow (see Map 1). Except for California City, which is 
located in the central part of the Mohave ground squirrel's range (see 
map 1), these cities make up almost all the incorporated lands within 
the squirrel's range. Not all the incorporated lands within these 
cities are developed; however, because of the proximity to existing 
infrastructures, we expect that future growth will take place in these 
incorporated areas. We cannot predict with any certainty how much or 
which of these areas will be developed in the next 20-30 years. 
Currently, about 2.6 percent of the range of the squirrel has been lost 
to urban and rural development. The development of all incorporated 
areas would result in the loss of approximately 9-10 percent of the 
Mohave ground squirrel's range; this number includes the 2.6 percent of 
the range already lost to development. However, this is highly unlikely 
because we expect very limited development of California City (or 2.45 
percent of the species' range), which is the largest incorporated area 
within the range of the squirrel.
    OHV recreational use occurs throughout much of the range of the 
Mohave ground squirrel. However, impacts to the Mohave ground squirrel 
and its habitat occur mainly in the most heavily used areas (management 
areas, spill-over zones, and high-use areas). If we assume that all 
habitat in the management areas, spill-over zones, and high-use areas 
has been severely impacted, then about 6.6 percent of the range of the 
Mohave ground squirrel has been lost to OHV use. However, we know that 
the Mohave ground squirrel continues to occur on at least one of the 
four management areas. Areas of lesser use (e.g., existing unpaved 
roads and trails) result in the loss of habitat, and vehicle activity 
can crush Mohave ground squirrels. However, the significance of such 
losses is undocumented for the Mohave ground squirrel and does not 
result in the total fragmentation of habitat, as unpaved roads and 
trails are not barriers to Mohave ground squirrel movement (Leitner 
2010, in litt.). In addition, the BLM, through implementation of the 
WEMO Plan, has no plans to designate additional high-use areas or roads 
and trails for the next few decades, has closed 45 percent of the roads 
and trails in the DWMAs and 90 percent in the Rand Mountains ACEC (BLM 
et al. 2005, chapter 2, p. 167), is restoring habitat in areas of 
closed roads and trails, is increasing enforcement, and is revising its 
route designation to minimize damage to public resources and harassment 
and disruption of wildlife and habitat.
    Several highways and roads cross the western Mojave Desert. This 
network of roads potentially impacts the Mohave ground squirrel and its 
habitat by direct mortality, loss of habitat from initial construction, 
introduction of invasive plants, and alteration of habitat upslope and 
downslope from hydrologic and erosion effects. One new highway is 
proposed in the southern portion of the range of the Mohave ground 
squirrel, and two highways are proposed for widening, which combined 
would result in the loss of at most 0.18 percent of the range of the 
squirrel. Although there is no information specific to the Mohave 
ground squirrel, roads are known in some cases to affect species and 
their habitat beyond the loss of habitat from construction of the road 
itself. This road-effect zone can have varying degrees of both positive 
and negative impacts, with the width of the zone varying with the 
species affected, location, habitat, road width, and traffic density. 
There is research that indicates that the effects of roads on small 
mammals in the desert are neutral to slightly positive. Assuming the 
worst case scenario that such a road-effect zone exists for the Mohave 
ground squirrel, and its impacts to the species' habitat are severe, we 
estimate that about 0.74 percent of the range could be lost.
    Military operations vary in their magnitude and intensity of 
impacts to Mohave ground squirrel habitat. Ground force training 
activities that use live ammunition, ordnance, and tracked and wheeled 
vehicles remove vegetation, compact the soil, and cause fires that 
remove perennial plants. These activities, including the Fort Irwin 
expansion area, occur on about 8.2 percent of the range of the Mohave 
ground squirrel. Bombing and weapons testing often result in intense 
disturbance in small areas while large buffer areas remain undisturbed. 
Flight-testing and training have limited if any ground impacts. 
Training areas for the military bases in the western Mojave Desert have 
buffer areas where surface disturbance is limited, or not allowed. 
However, much of the habitat on the three major bases in the western 
Mojave Desert, especially EAFB and NAWS, is protected from human 
impacts, such as urban and rural development, OHV recreational use, 
agriculture, and grazing, because these activities are not compatible 
with the military mission. Approximately 37.2 percent of the range of 
the Mohave ground squirrel occurs within the boundaries of Fort Irwin, 
EAFB, and NAWS. Although about 8.2 percent of the military land is 
intensively used for military operations, much of the remainder of its 
range within these DOD facilities is not heavily used, and large 
undisturbed areas are needed to test aerial vehicles and weapons and to 
act as buffer areas around target sites. To maintain the ongoing 
mission of the military, these large, undisturbed areas must remain 
undeveloped. Thus, while habitat for the Mohave ground squirrel is 
severely impacted in some areas by military operations, there are 
extensive areas where it does not experience these impacts.
    Several renewable energy projects and utility lines have been 
constructed or are proposed for construction in the range of the Mohave 
ground squirrel. Besides the direct loss of potentially large areas of 
habitat from the construction of new facilities, new and existing 
energy projects can also facilitate an increased presence of predators 
and promote invasive plants. Solar projects are likely to be the most 
destructive to Mohave ground squirrel habitat because these projects 
are situated in relatively flat or gently sloping areas that are 
preferred by the squirrel and because all vegetation is removed during 
construction and operation. There are two existing solar projects 
within the range of the squirrel, which make up about 0.07 percent of 
the range. Both of these projects are on private land; there are no 
projects at the present time on BLM or DOD land within the range of the 
squirrel. Unlike solar projects, wind turbines are often situated on 
ridges and hilltops, which are not the squirrel's preferred habitat, 
and geothermal energy only occurs in two areas within the range of the 
squirrel. Also, all vegetation is not cleared during the construction 
of wind and geothermal projects. Existing wind projects are on private 
land on the western edge of the squirrel's range and make up about 0.1 
percent of the range. There are no wind projects on BLM or DOD land at 
the present time. There is one large geothermal project on Federal land 
that makes up about 2 percent of the range, although much of the 
habitat in this area has not been destroyed.

[[Page 62242]]

Combined, existing renewable energy projects make up about 2.2 percent 
of the range of the Mohave ground squirrel.
    Several renewable energy projects have been proposed on both 
Federal and private land in the range of the Mohave ground squirrel. 
However, at the present time, there is a great deal of uncertainty as 
to the number, size, and location of future energy development and its 
potential impact on the Mohave ground squirrel. This uncertainty is 
caused by a number of factors, including the overlap of proposed 
projects, the cost of supplying renewable energy compared to other 
energy sources, and the uncertainty of whether or not the December 2011 
construction deadline for funding under the American Recovery and 
Reinvestment Act of 2009 will be extended. Proposals for solar and wind 
projects on DOD land, which include about 27 percent of the range of 
the Mohave ground squirrel, would encompass about 0.3 percent of the 
range, if constructed. Proposed solar and wind projects on BLM land, 
which includes about one third of the range of the squirrel, would 
encompass about 2.2 percent of the range, almost all of which is wind 
energy. However, this is likely an overestimate because not all of the 
proposed projects would likely be built. In addition, there is a 1 
percent cap on development in the DWMAs and MGSCA and the BLM would 
require a 5:1 mitigation ratio on all types of development in the MGSCA 
and DWMAs and a 1:1 mitigation ratio outside these areas. Also, the 
BLM's draft PEIS on solar energy development has identified four 
proposed SEZs, none of which are within the range of the squirrel.
    Proposals for new geothermal development on Federal land amount to 
only about 0.08 percent of the range of the Mohave ground squirrel. 
Although unlikely, if all proposed projects on Federal land, which 
makes up about 62 percent of the range, were constructed they would 
make up about 2.5 percent of the range. There are also proposals on 
private land, which would encompass about 1.2 percent of the squirrel's 
range, but many of these are proposed for land that has already been 
converted to agriculture. Therefore, under the worst case scenario, if 
we assume all proposed projects are constructed, construction of all 
renewable energy projects destroys all habitat, and all the habitat 
that is lost is suitable for Mohave ground squirrels, then an 
additional 3.7 percent of habitat could be lost. However, even in this 
worst case, large tracts of habitat would remain untouched, especially 
on Federal land.
    Livestock grazing occurs throughout portions of the range of the 
Mohave ground squirrel. The available information on the effects of 
livestock grazing on the Mohave ground squirrel is limited to a study 
on dietary overlap between cattle and Mohave ground squirrels; the 
study provided no indication that this overlap was adversely affecting 
the Mohave ground squirrel. Other studies in the Mojave Desert have 
described the general impacts of livestock grazing, particularly 
overgrazing, on soils and vegetation, which may result in habitat 
degradation but rarely habitat loss. The greatest ground-disturbance 
impact of grazing occurs at and near stock tanks and other water 
sources where cattle congregate. However, these areas make up a small 
percent of the range of the Mohave ground squirrel. The BLM's recent 
implementation of public land health standards and guidelines, which 
include eliminating or reducing grazing in some areas in the range of 
the Mohave ground squirrel, should improve the conditions of the soils 
and vegetation, including in the MGSCA and DWMAs. Over time, these 
changes are likely to improve the condition of soils and vegetation in 
the range of the Mohave ground squirrel.
    Agricultural activities are ongoing in the range of the Mohave 
ground squirrel. Agricultural development is focused in three areas: 
the western Antelope Valley, an area south of EAFB, and the Mojave 
River Valley and results in the direct loss of Mohave ground squirrel 
habitat. However, this loss is estimated to be less than 1 percent of 
the range of the Mohave ground squirrel. Operational impacts in 
agricultural areas may also include exposing Mohave ground squirrels 
and their forage to pesticide contamination. We found no information 
that pesticide use is adversely affecting the Mohave ground squirrel or 
its habitat. We also found no information that agricultural development 
and associated impacts would likely increase in the western Mojave 
Desert. The cost of irrigation has risen to a level that discourages 
extensive conversion of desert scrub habitat to agriculture, and 
instead, some agricultural lands are being converted to residential and 
commercial development.
    Mining activities have been ongoing in the western Mojave Desert 
for more than a century. Mining activities have impacts to the Mohave 
ground squirrel similar to urban and rural development and OHV 
recreational use, but on a more localized and limited scale. BLM lands 
are open to mining unless otherwise withdrawn; however, the number of 
active mines is small when compared to the number of inactive mines. 
There is no commercial mining on DOD lands, and there are few large 
mines in the range of the Mohave ground squirrel.
    Average temperatures have been rising in the western Mojave Desert, 
and this trend will likely continue because of climate change. Climate 
change may also affect precipitation and the severity, duration, or 
periodicity of drought. However, there is a great deal of uncertainty 
as to the rate at which the average temperature may increase, and the 
effect of climate change on both precipitation and drought. In addition 
to the uncertainty associated with how the overall climate of the 
Mojave Desert may change, the impact of climate change on the Mohave 
ground squirrel will depend on a complex array of other factors, 
including how the species and its habitat respond to climate change. In 
light of all the factors involved, we are not aware of information that 
would allow us to make a meaningful projection on the impact of climate 
change on the Mohave ground squirrel.
    We now look at the impacts of urban and rural development, OHV 
recreational use, transportation infrastructure, military operations, 
energy development, livestock grazing, agriculture, mining, and climate 
change, cumulatively. Many acres of Mohave ground squirrel habitat have 
been lost to these impacts and additional habitat is expected to be 
lost in the future. The greatest impacts have resulted from urban and 
rural development. Impacts from development as well as those from 
agriculture have and continue to be mainly concentrated on private 
lands in the southern portion of the range of the Mohave ground 
squirrel. Habitat loss due to military operations has been concentrated 
in the NTC in the easternmost portion of the squirrel's range. Other 
impacts, including heavy-use OHV recreation and transportation 
infrastructure, existing and proposed renewable energy development, and 
grazing are more dispersed throughout the species' range. Based on a 
worst-case analysis, we estimate that in the next 20-30 years about 
32.2 percent of the range of the Mohave ground squirrel could be lost. 
However, we expect that the actual loss during this timeframe will be 
much less because this estimate is based on a series of worst-case 
assumptions.
    For urban and rural development, we expect the loss of habitat to 
be less because California City, which is the largest incorporated area 
in the Mojave Desert, has developed very little of its incorporated 
area in the past 46 years

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and because the CDFG would likely require mitigation for the loss of 
Mohave ground squirrel habitat as part of the permitting process under 
CESA (see Factor D, ``State Laws and Regulations'').
    For transportation infrastructure, we calculated the loss of 
habitat from road construction along the entire highway length, which 
includes portions located within incorporated areas and currently 
developed areas, thus double counting these impacts within the range of 
the Mohave ground squirrel. In addition, we assumed a road-effect zone 
for the Mohave ground squirrel, although there may be little or no such 
zone for the squirrel, as several studies indicate that the impacts of 
highways are generally neutral to slightly positive for small mammals.
    For military operations, we assumed that the entire NTC including 
the expansion area would be used for ground forces training resulting 
in the loss of all Mohave ground squirrel habitat within this area. In 
reality, not all of this area will be used for training and some areas 
have been set aside as buffer zones needed to shield the training 
activities from civilian uses on lands adjacent to the base.
    For renewable energy, although the area requested for development 
may be large, the actual footprint of the projects is small, much of 
the Mohave ground squirrel habitat within the project boundary for wind 
and geothermal will not be developed, and many of these projects are 
proposed for areas that were previously cleared and used for 
agriculture. We also believe the total loss from renewable energy will 
be less because habitat loss is frequently mitigated by the acquisition 
and enhancement of habitat for the Mohave ground squirrel. In the 
squirrel's range, the CDFG may require mitigation for development on 
private land and for Federal projects (see Factor D, ``State Laws and 
Regulations''). The BLM requires 5:1 mitigation for projects in the 
DWMAs and MGSCA and 1:1 elsewhere. Even if the worst case occurs and 
all 32.2 percent of the range is eventually lost, we expect that most 
of the remaining area will remain relatively undisturbed. More than 80 
percent of the remaining land is Federal, and includes the MGSCA and 
DWMAs, which are managed at least in part for the Mohave ground 
squirrel, and large areas of DOD land, especially on EAFB and NAWS, 
which we expect to remain undisturbed in support of the military's 
mission. Of particular importance to the Mohave ground squirrel, much 
of the remaining lands are contiguous and provide connectivity from the 
northern end of the range to well south of SR-58 in the southern 
portion of the range. These lands contain most or all the habitat 
within the eight important population areas and include habitat that 
provides for connectivity among the eight areas.
    Based on this information, we conclude that the cumulative impacts 
of urban and rural development, OHV recreational use, military 
operations, energy development, transportation infrastructure, grazing, 
agriculture, mining, and climate change do not currently constitute a 
significant threat to the Mohave ground squirrel in relation to the 
present or threatened destruction, modification, or curtailment of its 
habitat or range, nor do we anticipate that they will pose a threat in 
the future.

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

    We found no known commercial or recreational utilization of the 
Mohave ground squirrel. Scientific and educational activities 
associated with the Mohave ground squirrel are controlled by the CDFG 
through the issuance of scientific research permits.
    Based on our review of the best available scientific and commercial 
information, we found no evidence of threats from overutilization for 
commercial, recreational, scientific, or educational purposes affecting 
the Mohave ground squirrel or potential risks in the future. We 
therefore conclude that overutilization for commercial, recreational, 
scientific, or educational purposes is currently not a threat to the 
Mohave ground squirrel across its range, nor do we anticipate 
overutilization for commercial, recreational, scientific, or 
educational purposes posing a threat in the future.

Factor C: Disease or Predation

Disease
    Although other species of ground squirrels are subject to sylvatic 
plague (Foley et al. 2007, p. 1; CA Dept. Public Health 2008, p. 2), 
there is no evidence of its presence in Mohave ground squirrels 
(Leitner 2005, PowerPoint presentation, slide 11). There is no 
information of any other disease present in the Mohave ground squirrel. 
Based on our review of the best available scientific information, we 
found no research or observational evidence that documents or suggests 
that disease is affecting the Mohave ground squirrel (Service and CDFG 
1998, p. 2; Leitner presentation, 2005).
Predation
    Small rodents such as the Mohave ground squirrel are important prey 
for many species. The Mohave ground squirrel is potentially prey to a 
host of native predators, including the coyote; American badger; bobcat 
(Lynx rufus); various species of raptors, such as the golden eagle, 
prairie falcon, and red-tailed hawk (Gustafson 1993, p. 88); common 
raven (Boarman 1993, p. 2); and various species of rattlesnakes 
(Gustafson 1993, p. 88). In addition, domestic cats and dogs may also 
prey on Mohave ground squirrels. Of 36 Mohave ground squirrels radio-
collared in 1995 and 1997, 12 (33 percent) were believed to be lost to 
predation (Harris and Leitner 2005, pp. 190-191). Although not directly 
observed, mortality from predation was determined from a combination of 
blood or toothmarks on radio collars or the discovery of collars at a 
raptor or raven perch site. Overall, predation on Mohave ground 
squirrels has seldom been observed, and the impact of predation on the 
species is not known. Small rodents are important prey for many of the 
species listed above, and predation on small rodents, including the 
Mohave ground squirrel, can be high.
    The coyote is a common predator in the western Mojave Desert. 
Although the coyote is likely a predator of the Mohave ground squirrel, 
we found no recorded observations of coyotes preying on Mohave ground 
squirrels or fecal analysis of coyote scat that contained remains of 
Mohave ground squirrels. In addition, we found no information 
documenting that the coyote population has increased or is expected to 
increase in the western Mojave Desert, or the level of predation by the 
coyote on the Mohave ground squirrel has increased or is expected to 
increase, or that coyote predation is having an adverse impact on the 
species.
    The increased presence of domestic dogs and cats in the western 
Mojave Desert may impact the Mohave ground squirrel. Feral or free-
ranging domestic dogs have been identified as potential predators of 
the Mohave ground squirrel (D. LaBerteaux, cited in Gustafson 1993, 
Appendix, p. 86). The BLM (BLM et al. 2005, chapter 3, p. 65) noted 
``feral dogs are a problem in several areas'' of the western Mojave 
Desert ``where they may kill Mohave ground squirrels.'' The BLM found 
that dogs are most common in the habitat adjacent to urbanized areas 
(BLM et al. 2005, chapter 3, p. 96). For example, BLM survey results 
showed that dog sign occurred on 88

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percent of the transects surveyed in proximity to urbanized areas but 
occurred on less than 1 percent of the transects surveyed in the 
undeveloped Fremont-Kramer and Superior-Cronese DWMAs (BLM et al. 2005, 
chapter 3, p. 104). For those transects within the range of the Mohave 
ground squirrel, 4 percent had dog sign (BLM et al. 2005, chapter 3, p. 
156). Although these data indicate that dogs, based on the presence of 
sign, occur in desert habitats within the range of the Mohave ground 
squirrel, Leitner (2005 presentation) indicated that no data have been 
collected that document that dogs have an impact on the species. In our 
review of the available information, we did not find any indication 
that feral or domestic dogs prey on Mohave ground squirrels or dig up 
Mohave ground squirrel burrows. In the WEMO Plan, the BLM stated that 
failure to implement a feral dog management plan is not likely to 
adversely affect the Mohave ground squirrel, as ``feral dog predation 
has not been documented as a significant threat'' (BLM et al. 2005, 
chapter 4, p. 153). Therefore, we conclude that domestic or feral dogs 
are not a major predator of the Mohave ground squirrel and their rate 
of predation is not likely to increase in the future.
    Domestic cats may have increased near urban expansion areas in the 
western Mojave Desert. Domestic cats are efficient predators of small 
birds and mammals (Harrison 1992, p. 10). Gustafson (1993, p. 30-31) 
postulated that domestic cats may kill Mohave ground squirrels. 
However, Leitner (2005 presentation) stated there is no documentation 
of the impact of predation by domestic cats on Mohave ground squirrels. 
Although it is likely that domestic cats have increased in the western 
Mojave Desert with the increased human population in the past few 
decades, we were unable to find information documenting that domestic 
cats prey on Mohave ground squirrels.
    The common raven is a likely predator of the Mohave ground 
squirrel. Harris and Leitner (2005, pp. 190-191) found empty radio 
collars from Mohave ground squirrels under raven perch sites and 
concluded this was evidence of predation by common ravens on Mohave 
ground squirrels. Common ravens kill many types of animals for food, 
including ground squirrels (Boarman 1993, p. 2). Kochert et al. (1976, 
in Knight and Call 1980, p. 17) reported that Townsend ground squirrels 
(Urocitellus townsendii) in Idaho comprised 93 and 70 percent of the 
food biomass of nesting ravens during a 2-year study.
    The common raven population increased more than 700 percent in the 
western Mojave Desert from 1986 to 2004 (Boarman and Kristan 2006, p. 
2; Service 2008, p. A-16), likely in response to increased urbanization 
and recreational use, which provide common ravens with an artificial 
source of reliable and widespread food, water, nest sites, roost sites, 
and perch sites (Boarman 2002, p. 1). In most locations, human-created 
nest, roost, and perch sites, including transmission line towers, 
telephone and streetlight poles, buildings, billboards, and fences, 
provide the common ravens with previously unavailable high perches, 
which allow them to hunt and scavenge more effectively, or with less 
energy expenditure than required by flight or from a low perch (Boarman 
1993, p. 2).
    Although common ravens likely prey on Mohave ground squirrels, and 
the amount of predation has likely increased as the population of 
ravens has increased, the available information does not indicate that 
this level of predation is having an adverse effect on Mohave ground 
squirrel populations.
Summary of Factor C
    In summary, we found no information that disease is a threat to the 
Mohave ground squirrel throughout its range. Regarding predation, 
beyond the general knowledge of natural and potential predators of the 
Mohave ground squirrel, we found no information on the observance or 
extent of predation by coyotes, domestic dogs or cats on the Mohave 
ground squirrel, and no information suggesting that predation is 
affecting Mohave ground squirrel abundance, distribution, or long-term 
survival. We did find circumstantial information that predation by the 
common raven likely occurs on the Mohave ground squirrel. We also found 
information that the number of common ravens in the western Mohave 
Desert has increased substantially in the last few decades. We 
acknowledge that the level of predation by the common raven on the 
Mohave ground squirrel may have increased, but the available 
information does not indicate that this level of predation is adversely 
affecting Mohave ground squirrel abundance, distribution, or long-term 
survival. Therefore, based on our review of the best available 
scientific and commercial information, we conclude that predation is 
currently not a significant threat to the Mohave ground squirrel 
throughout its range, nor do we anticipate predation posing a threat in 
the future.

Factor D: The Inadequacy of Existing Regulatory Mechanisms

    The Act requires us to examine the adequacy of existing regulatory 
mechanisms with respect to those existing and foreseeable threats that 
may place the Mohave ground squirrel in danger of becoming either 
endangered or threatened. Existing regulatory mechanisms that provide 
some protection for the Mohave ground squirrel include local land use 
ordinances and processes, State laws and regulations, and Federal laws 
and regulations. The habitat of the Mohave ground squirrel spans 
private lands, local government lands, State lands (California State 
Parks, CDFG, and California State Land Commission), and Federal lands 
(BLM, DOD, National Park Service (NPS), and U.S. Forest Service (USFS)) 
in California.
Local Land Use Ordinances and Processes
    Approximately 31 percent of the range of the Mohave ground squirrel 
is privately owned, or owned by local governments. We found little in 
the way of local planning and enforceable zoning regulations specific 
to the Mohave ground squirrel. Approximately 11.9 percent of the range 
of the Mohave ground squirrel lies within San Bernardino County, but 
the County has regulatory authority over only a portion of these lands. 
The County of San Bernardino online ``Biotic Resources Overlay Map'' 
includes information to assist both the property developer and County 
land use planner in identifying lands that may support the Mohave 
ground squirrel. If a proposed discretionary project is within this 
overlay area, the County would accept an application for development 
only after a focused survey for the Mohave ground squirrel has been 
completed (Zias-Roe 2010, pers. comm.). If the survey results are 
positive, the County would require demonstration of compliance with 
CESA. Similar planning tools are used by municipalities such as the 
Town of Apple Valley (2009, p. III-50 of the General Plan) for 
discretionary projects. The Mohave ground squirrel is usually not 
considered when implementing actions such as issuing building or 
grading permits.
State Laws and Regulations
    California laws and regulations that may benefit the Mohave ground 
squirrel include CESA and the California Environmental Quality Act 
(CEQA) (Public Resources Code sections 21000-21177). These laws provide 
broad

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authority to regulate and protect wildlife within the State, specific 
authority for lands directly owned by the State, and specific authority 
to require reduction of take of the species through minimization and 
mitigation of impacts from discretionary actions at a local or State 
government level.
    The State of California has broad authority to regulate and protect 
wildlife within its borders. The mission of the CDFG is ``to manage 
California's diverse fish, wildlife, and plant resources, and the 
habitats upon which they depend, for their ecological values and for 
their use and enjoyment by the public'' (CDFG 2005, p. 1). The CDFG 
does this through a variety of actions, including enforcing hundreds of 
laws and regulations related to fish, wildlife, and habitat; managing 
lands at wildlife areas, ecological reserves, and public access sites 
for ecological and recreational uses; and collecting and analyzing 
scientifically based data on the distribution and abundance of fish, 
wildlife, and native plant species and the natural communities and 
habitats in which they live. When implemented in the range of the 
Mohave ground squirrel, these actions benefit the species.
    One California law that addresses the conservation and protection 
of the Mohave ground squirrel is CESA, which was enacted in 1985. The 
Mohave ground squirrel is listed as threatened under CESA; CESA defines 
a threatened species as a native species that, although not presently 
threatened with extinction, is likely to become an endangered species 
in the foreseeable future in the absence of special protection and 
management efforts. CESA also declares that it is the policy of the 
State to conserve, protect, restore, and enhance any endangered or 
threatened species and its habitat. Take, as defined under CESA, of a 
threatened or endangered species is prohibited without first obtaining 
authorization from the CDFG.
    Because the Mohave ground squirrel is a threatened species under 
CESA, anyone wishing to capture or otherwise take a Mohave ground 
squirrel for scientific purposes must first obtain a memorandum of 
understanding (MOU) or a permit from the CDFG as described under 
California Fish and Game Code 2081(a) (CDFG 2003, p. 1). The issuance 
of the MOU or permit is a discretionary action by the CDFG. Under the 
California Fish and Game Code, the CDFG is charged with ensuring that 
any action it authorizes does not jeopardize the continued existence of 
the species. Therefore, the CDFG is not allowed by regulation to issue 
a permit that would result in the overutilization of the Mohave ground 
squirrel for scientific purposes.
    California Fish and Game Code section 2081, enacted in 1999, states 
that the CDFG may authorize, by permit, the take of an endangered and 
threatened species, if the take is incidental to an otherwise lawful 
activity and the impacts of the take are minimized and fully mitigated. 
Although CESA does not apply to Federal land management agencies 
conducting actions on Federal lands, it generally does apply to actions 
taken by non-Federal entities. Therefore, compliance with CESA is 
needed for many actions occurring in the range of the Mohave ground 
squirrel, including on Federal land. In addition, the State listing of 
the Mohave ground squirrel helps focus Federal land managers' attention 
on the species and consider impacts to the species when developing 
actions. Most Federal land managers would prefer to manage for a 
species to ensure it does not require the protections of the Act.
    Because CESA prohibits the taking of the Mohave ground squirrel 
without obtaining a permit, the CDFG requires that a standard survey 
protocol, which was developed by the CDFG in 1987 (Gustafson 1993, p. 
463) and revised in 2003, be used to determine the presence or absence 
of the Mohave ground squirrel on lands proposed for development. 
Therefore, the results obtained with the protocol are a critical 
component of the decision making process, and most of the information 
available on the distribution and abundance of the Mohave ground 
squirrel is based on the same results. The survey protocol specifies 
that a CDFG-approved, qualified biologist conduct a visual survey of 
the proposed project site. If the results are negative, a series of 
live grid traps are set during three periods. If the results for Mohave 
ground squirrels are negative after implementation of the survey 
protocol, the CDFG stipulates that the project site contains no Mohave 
ground squirrels, and development may occur without an incidental take 
permit and mitigation (CDFG 2003, p. 3). If Mohave ground squirrels are 
present at a proposed development, then CESA and California Fish and 
Game Code section 2081 require that the impacts be minimized and fully 
mitigated. The CDFG generally requires securing and managing existing 
habitat at another location for the Mohave ground squirrel. Thus, for 
every discretionary project with positive survey results, 
implementation of the proposed development with mitigation yields a net 
loss of acres of habitat for the Mohave ground squirrel, but the lands 
acquired for mitigation are managed to improve their habitat value and 
are secured in perpetuity for the Mohave ground squirrel.
    One major difference between CESA and the Act is that there is no 
requirement under CESA to develop and implement a recovery plan for a 
State-listed species. Consequently, with no recovery plan, there is no 
written guidance for Federal, State, and local agencies and the public 
to know what actions to implement and where to implement them to 
achieve the State's policy to conserve, protect, restore, and enhance 
the Mohave ground squirrel and its habitat.
    In evaluating the Mohave ground squirrel protocol, some scientists 
have identified potential problems with the protocol that raise into 
question the accuracy of the current survey technique (Brooks and 
Matchett 2002, p. 172). The survey protocol may yield false negative 
results or undersample the population. Mohave ground squirrels are 
difficult to trap, even in locations where they have been sighted (Hoyt 
1972, p. 7). Mohave ground squirrels have been observed approaching 
traps but not entering them (Leitner 2009, pers. comm.). In some cases, 
only a few squirrels have been trapped while several had been seen or 
heard calling in the same area (Urban et al. 2010, p. 1). In addition, 
the grid trap arrangement is not necessarily the best trapping method 
to use for detecting rare small mammals. For example, in comparing grid 
and transect trap arrangements for small mammals, transect arrangements 
yielded more total captures, more individual captures, and more species 
than grid arrangements (Pearson and Ruggiero 2003, p. 457). The 
differences between the two methods tend to be greatest when small 
mammals are least abundant (Pearson and Ruggiero 2003, p. 457), as may 
be the case with the Mohave ground squirrel. Recently, a video survey 
method was compared to the live trapping survey protocol at two 
locations. The Mohave ground squirrel detection rate for the video 
method was greater than for the trapping protocol (Delaney 2009, p. 12) 
(see ``Abundance and Trend'' section).
    The CDFG acknowledges that a negative survey result does not mean 
that the Mohave ground squirrel does not occur on the site, or that 
take will not occur (CDFG 2003, p. 3). The survey protocol, including 
the trapping component of the protocol, may result in a false negative 
finding (e.g., the Mohave ground squirrels may be present but the 
available data from the

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survey protocol indicates they are not present). The purpose of the 
survey protocol is to determine presence and therefore if take will 
occur. Its purpose is not to provide population information on 
population size, status, or trend.
    In summary, CESA provides some protection for the Mohave ground 
squirrel from take and habitat loss. However, the benefit of CESA to 
the squirrel may depend on the ability to detect the species on a 
proposed development site. If squirrels are present on a site but not 
detected with the survey protocol, which is known to occur based on 
subsequent observations, then the project is implemented with no 
mitigation for the Mohave ground squirrel under CESA. If a project 
proponent assumes presence of the Mohave ground squirrel at a project 
site or if squirrels are detected during the survey protocol, then CESA 
requires mitigation for the take of the Mohave ground squirrel. Thus, 
CESA provides some benefit to the Mohave ground squirrel and its 
habitat.
    CEQA is a regulatory mechanism that affords protection for the 
Mohave ground squirrel in certain circumstances. CEQA requires review 
of environmental impacts for any proposed discretionary project that is 
undertaken, funded, or permitted by a State or local governmental 
agency, and public disclosure of these findings. Section 15065 of the 
CEQA guidelines requires a finding of significance if the project has 
the potential to ``reduce the number or restrict the range of a rare 
(threatened) or endangered plant or animal.'' The Mohave ground 
squirrel is such a species, because as stated above it is listed as 
threatened by the State of California. In general, if a proposed 
project in Mohave ground squirrel habitat requires a discretionary 
permit from a State or local agency, that public agency is required to 
prepare a public document under CEQA that analyzes the impacts of the 
proposed action on the species and requires mitigation for the impacts. 
However, if economic, social, or other conditions make it infeasible to 
mitigate one or more significant effects of a project on the species, 
the project may nonetheless be carried out or approved at the 
discretion of a public agency if the project is otherwise permissible 
under applicable laws and regulations (CEQA Guidelines section 15093), 
even though the project may cause significant environmental damage, 
such as destruction of a listed species or its habitat.
    Although CEQA may provide protection for the Mohave ground squirrel 
in certain circumstances, there are several statutory and categorical 
exemptions to CEQA which exempt proposed projects that are undertaken, 
funded, or permitted by local or State agencies from the requirements 
of public disclosure and mitigation. These include certain mass transit 
projects, certain planning documents, certain pipeline projects, 
certain ministerial (non-discretionary) projects (Title 14 California 
Code of Regulations, chapter 3, Article 18, sections 15260 to 15285), 
grazing (Rebecca Jones 2010, in litt.), and in-fill development 
projects (Article 19, sections 15300 to 15333). Also exempt are 
projects that are approved by popular vote that do not involve a public 
agency-sponsored initiative (Title 14 California Code of Regulations, 
chapter 3, Article 20, section 15378).
    The exemption of ministerial-permitted projects is an important 
consideration in evaluating the level of protection of the Mohave 
ground squirrel and its habitat afforded by CEQA. On private land, CEQA 
applies only to discretionary actions, such as major changes in zoning 
or requests for a conditional use permit. Building or grading permits 
or other development projects with minor, or no, changes to existing 
land use or zoning designations are considered ministerial by the local 
development agencies and are not subject to CEQA. Although minor on an 
individual basis, cumulatively, these activities can result in the take 
of the species and the loss, fragmentation, and degradation of habitat 
with no mitigation under CEQA. These activities, however, would still 
be subject to the requirements of CESA.
    Another California law that could benefit the Mohave ground 
squirrel is the Natural Communities Conservation Planning Act (NCCPA). 
NCCPA provides for voluntary cooperation among the CDFG, landowners, 
and other interested parties to develop natural community conservation 
plans (NCCPs) that provide for early coordination of efforts to protect 
listed species or species that are not yet listed. NCCPA identifies and 
provides for the regional or area-wide protection of plants, animals, 
and their habitats, including listed species, while allowing compatible 
and appropriate development activity. NCCPA could not only benefit the 
Mohave ground squirrel, but could also benefit local communities in the 
western Mojave Desert, which, under the NCCPA, could obtain 
authorization to take the Mohave ground squirrel while allowing for 
reasonable development. There is no NCCP for the Mohave ground squirrel 
at this time; however, there is one under development for renewable 
energy in the California desert. If the renewable energy NCCP is 
finalized and implemented, some areas inhabited by the Mohave ground 
squirrel would be included in the plan area.
    In addition to these laws and regulations, California also manages 
lands in the range of the Mohave ground squirrel for native habitat. 
These lands include about 22,000 ac (8,900 ha) managed by the 
California Department of Parks and Recreation and 15,000 ac (6,070 ha) 
managed by the CDFG.
Federal Laws and Regulations
    Federal agencies are responsible for managing approximately 66 
percent of the range of the Mohave ground squirrel (Defenders of 
Wildlife and Stewart 2005, pp. 39-40). The Federal agencies with the 
largest land management authority for these lands are the BLM and the 
DOD (see Table 1 and Factor A).
    Several Federal laws and regulations that may benefit the Mohave 
ground squirrel include the National Environmental Policy Act of 1969 
(42 U.S.C. 4321 et seq.), as amended (NEPA); Federal Land Policy and 
Management Act of 1976 (43 U.S.C. 1701 et seq.) (FLPMA); Public 
Rangelands Improvement Act of 1978 (43 U.S.C. 1752 et seq.); Wild Horse 
and Burro Protection Act of 1971 (16 U.S.C. 1331 et seq.); and the 
Sikes Act Improvement Act (16 U.S.C. 670a-670o), as amended (Sikes 
Act). These laws provide authority to conserve habitat and mitigate for 
adverse impacts to habitat, including habitat for the Mohave ground 
squirrel. In addition, if the Mohave ground squirrel occurs on the same 
patch of habitat as a federally listed species (e.g., desert tortoise 
(Gopherus agassizii) or Astragalus jaegerianus (Lane Mountain milk-
vetch)), the Mohave ground squirrel may benefit from the protections 
afforded these species under the Act.

Bureau of Land Management

    About 37 percent of the land (1,804,139 ac (730,112 ha)) within the 
range of the Mohave ground squirrel is administered by the BLM 
(Defenders of Wildlife and Stewart 2005, pp. 39-40). As a Federal 
agency, whenever BLM proposes to implement or authorize any action on 
lands that it manages, it must comply with NEPA. NEPA requires all 
Federal agencies to formally document and publicly disclose the 
environmental impacts of their proposed actions and management 
decisions.
    In addition, 40 CFR 1500.2 requires all Federal agencies, to the 
fullest extent possible, to use all practicable means, consistent with 
the requirements of NEPA and other essential considerations of national 
policy, to

[[Page 62247]]

restore and enhance the quality of the human environment and avoid or 
minimize any possible adverse effects of their actions upon the quality 
of the human environment. When implementing NEPA within the range of 
the Mohave ground squirrel, all Federal agencies must consider their 
potential impacts on the species and identify and consider appropriate 
mitigation measures.
    FLPMA is the primary Federal law governing most land uses on BLM 
lands. FLPMA established a public land policy for the BLM; it provides 
for the management, protection, development, and enhancement of the BLM 
lands. Public lands are managed for multiple use and sustained yield. 
Under its multiple use mandate, the BLM allows grazing, mining, OHV 
use, energy production, and other uses on public lands. The BLM also 
has the flexibility under FLPMA to establish and implement special 
management areas such as ACECs and research natural areas, where the 
BLM can limit or exclude surface disturbance activities that adversely 
affect sensitive species, such as the Mohave ground squirrel.
    FLPMA directs the development and implementation of resource 
management plans (RMPs), which direct management at a local level, and 
requires public notice and participation in the formulation of such 
plans and programs for the management of BLM lands. RMPs authorize and 
establish allowable resource uses, resource condition goals and 
objectives to be attained, program constraints, general management 
practices and sequences, intervals and standards for monitoring and 
evaluating RMPs to determine effectiveness, and the need for amendment 
or revision (43 CFR 1601.0-5(k)).
    Section 601 of FLPMA was written specifically for the CDCA, which 
includes the western Mojave Desert. In this section, Congress noted the 
fragility of the California desert ecosystem that is ``easily scarred 
and slow to heal; the historical, scenic, archeological, environmental, 
biological, cultural, scientific, educational, recreational, and 
economic resources in the California desert; and that certain rare and 
endangered species of wildlife, plants, and fishes, and numerous 
archeological and historic sites, are seriously threatened by air 
pollution, inadequate Federal management authority, and pressures of 
increased use, particularly recreational use, which are certain to 
intensify because of the rapidly growing population of southern 
California.'' Congress charged the BLM with developing and implementing 
an RMP for the CDCA that provides for the immediate and future 
protection and administration of the public lands in the California 
desert within the framework of a program of multiple-use and sustained 
yield, and the maintenance of environmental quality. Within the range 
of the Mohave ground squirrel, the current BLM land management 
documents are the California Desert Conservation Area (CDCA) Plan 1980, 
as amended (BLM 1999) and other amendments to the CDCA Plan, including 
the WEMO Plan and EIS (BLM et al. 2005). The WEMO Plan is the RMP for 
the western portion of the CDCA.
    The Mohave ground squirrel is designated as a sensitive species on 
BLM lands. The management guidance for special status species under BLM 
Manual 6840-Special Status Species Management states that ``Bureau 
sensitive species will be managed consistent with species and habitat 
management objectives in land use and implementation plans to promote 
their conservation and to minimize the likelihood and need for listing 
under the ESA'' (BLM 2008, p. 05V). BLM Manual 6840 further requires 
that RMPs should address sensitive species, and that implementation 
``should consider all site-specific methods and procedures needed to 
bring species and their habitats to the condition under which 
management under the Bureau sensitive species policies would no longer 
be necessary'' (BLM 2008, p. 2A1).
    The WEMO Plan is the up to 30-year RMP whose boundary includes most 
of the current habitat of the Mohave ground squirrel. One of the 
purposes of the WEMO Plan was to develop and implement management 
strategies that would conserve the Mohave ground squirrel throughout 
the western Mojave Desert (BLM et al. 2005, p. ES-1). This RMP contains 
specific measures pertinent to the management of the Mohave ground 
squirrel and its habitat. The BLM designated the MGSCA, a wildlife 
habitat management area (WHMA), on BLM lands in the northern part of 
the species' range (BLM et al. 2005, chapter 2, p. 203; LaPre 2009, in 
litt.). Within the MGSCA boundary, land ownership is BLM (1,308,877 ac 
(529,686 ha)) with private land (420,000 ac (169,969 ha)) scattered 
among the BLM land (BLM et al. 2005, chapter 2, p. 203). Thus, about 75 
percent of the land within the MGSCA is subject to the BLM's management 
protections for the MGSCA.
    Within the central and southern portion of the range of the Mohave 
ground squirrel are three ACECs, the Fremont-Kramer DWMA (513,918 ac 
(207,976 ha)), the Desert Tortoise Research Natural Area (DTNA), which 
is contained within the Fremont-Kramer DWMA, and the Superior-Cronese 
DWMA (641,917 ac (259,776 ha)) (BLM et al. 2005, chapter 2, p. 13). 
About 55 percent of the Fremont-Kramer, 59 percent of the Superior-
Cronese, and 92 percent of the DTNA lands within the ACEC boundaries 
are BLM lands. The BLM manages these ACECs at a greater level of 
protection for wildlife and habitat than the MGSCA. It does not allow 
certain land uses, such as solar energy development, in ACECs, and 
acquires private land within DWMA boundaries in areas that overlap the 
range of the Mohave ground squirrel (BLM et al. 2005, chapter 2, pp. 
28, 70). The Mohave ground squirrel will benefit from the management of 
these three ACECs and the MGSCA because they are contiguous with each 
other, which will facilitate management of these lands as blocks of 
unfragmented habitat outside military bases (see Map 2).
    The Public Rangelands Improvement Act established a national policy 
and commitment to improve the conditions on public rangelands. Its goal 
is to improve range condition, which relates to wildlife habitat and 
plant communities. The BLM has specific regulatory authority for 
grazing management provided at 43 CFR 4100 (Regulations on Grazing 
Administration Exclusive of Alaska). Livestock grazing permits and 
leases contain terms and conditions to achieve management and resource 
condition objectives on the BLM lands, and to ensure that habitats are, 
or are making significant progress toward, being restored or maintained 
for BLM special status species (43 CFR 4180.1(d)), which include the 
Mohave ground squirrel. Examples of the actions BLM has taken to 
accomplish this goal include: Closing some sheep allotments, removing 
sheep from allotments in the MGSCA when ephemeral plants are no longer 
the primary forage used by sheep, eliminating ephemeral grazing for 
cattle in the DWMAs, and excluding cattle grazing in the spring in 
DWMAs when annual plant productivity is low (BLM et al. 2005 chapter 2, 
pp. 131-135).
    In 1964, Congress enacted the Wilderness Act, with the intent of 
establishing a National Wilderness Preservation System composed of 
federally owned wilderness areas to be protected in their natural 
condition for the use and enjoyment of the people of the United States. 
A variety of activities are prohibited by the Wilderness Act within 
designated wilderness areas.
    As mentioned under Factor A, part or all of 14 designated 
wilderness areas are on BLM lands and in the range of the

[[Page 62248]]

Mohave ground squirrel. The Wilderness Act protects these areas from 
various forms of development and human activities that are stressors 
for the Mohave ground squirrel; however, the areas designated as 
wilderness within the range of the Mohave ground squirrel comprise 
about 4.6 percent of the species' range and are not contiguous. These 
areas include steep slopes and rocky substrates that would not provide 
suitable habitat for the Mohave ground squirrel but would contribute to 
connectivity among squirrel habitat.
    The Wild Horse and Burro Protection Act directs the BLM to protect 
these animals on public lands where they occurred when the law was 
enacted, and to manage them by removing excess animals to restore a 
thriving natural ecological balance to the range. This law enables the 
BLM to remove nonnative wild horses and burros that are degrading or 
destroying habitat within the range of the Mohave ground squirrel.
    To manage motorized access on BLM lands within the range of the 
Mohave ground squirrel, the FLPMA and its implementing regulations 
direct the BLM to locate trails in a manner to minimize impacts to the 
physical resources (i.e., soils, watershed, vegetation, air, and other 
resources), and to minimize harassment of wildlife or significant 
disruption of wildlife habitats (43 CFR 8342.1). To manage for the 
Mohave ground squirrel and other species, the BLM has implemented a 
program of OHV route obliteration and restoration and the signing of 
open routes to keep OHV activities aligned with what is permitted. In 
the central portion of the Mohave ground squirrel's range, the BLM 
implemented the Rand Mountain Fremont Valley Plan (Rand Plan) on 65,020 
ac (26,313 ha) between Ridgecrest and California City, which includes 
an area popular with OHV enthusiasts. The Rand Plan adopted a motorized 
vehicle access network, expanded the Rand ACEC by 13,120 ac (5,309 ha), 
reduced the multiple use class from Class M to Class L, acquired 
private lands, and withdrew land from mineral entry. Class L lands are 
intended to support limited use by activities that degrade the value of 
the land and to protect sensitive, natural, scenic, ecological, and 
cultural resource values. Class M lands have moderate use, and provide 
for a controlled balance between higher intensity uses and resource 
protection (BLM et al. 2005, chapter 3, p. 3). The BLM considered 
implementing the Rand Plan a high priority for Mohave ground squirrel 
conservation (BLM et al. 2005, chapter 3, p. 170) as it reduces impacts 
to the Mohave ground squirrel and its habitat from OHV recreation in 
the Plan area.
    Both FLPMA and the Mineral Leasing Act give the BLM the legal 
authority to regulate and condition energy permits. The Energy Policy 
Act of 2005 (42 U.S.C. 15801 et seq.) orders the identification of 
renewable energy sources and provides incentives for their development 
(42 U.S.C. 15851). This law and Presidential Executive Order 13121 
direct the production, purchase, and facilitation of development of 
renewable energy products by Federal entities and land management 
agencies. The ``Energy Development'' section of Factor A describes the 
development and operation of renewable energy projects, including 
recent increases in solar, wind, and geothermal energy development. All 
of these activities require ground disturbance, infrastructure, and 
ongoing human activities that could adversely affect the Mohave ground 
squirrel on the landscape.
    In summary, the BLM manages about one-third of the range of the 
Mohave ground squirrel. Under FLPMA, the BLM has designated three ACECs 
and a MGSCA, which are contiguous and will facilitate management of 
these lands (see Factor E). The BLM has a mandate to manage BLM lands 
for multiple-use, and has broad regulatory authority to plan and manage 
all land use activities on public lands, including energy development, 
OHV recreation, grazing, and other activities. As described in Factor 
A, these activities have the potential to impact the Mohave ground 
squirrel and its habitat. The BLM has developed mitigation measures for 
many of these activities that will reduce or eliminate the magnitude 
and severity of the impacts to Mohave ground squirrel habitat. In some 
cases, the BLM limits or prohibits activities on BLM lands with special 
designations because of incompatibility with those designations.

Department of Defense

    The U.S. Army's Fort Irwin, the U.S. Navy's NAWS, and the U.S. Air 
Force's EAFB include about 1,683,095 ac (681,127 ha) or 31.6 percent of 
the Mohave ground squirrel range. Additional DOD lands in the Mohave 
ground squirrel range (Air Force Plant 42 in Palmdale and Cuddeback 
Lake Air Force Range northeast of EAFB) comprises about 0.1 percent of 
the species' habitat. Three of the Mohave ground squirrel important 
population areas (Leitner 2008, p. 34) occur partly or entirely on 
these DOD lands (see Map 2). Part of the Coso Range-Olancha important 
population area is on NAWS, part of the Coolgardie Mesa-Superior Valley 
important population area is on Fort Irwin, and the EAFB important 
population area is within this military base.
    As Federal agencies, these DOD bases must formally document and 
publicly disclose the environmental impacts of their proposed actions 
and management decisions. Fort Irwin recently expanded its boundaries. 
Much of the expansion area is in the range of the Mohave ground 
squirrel. During the NEPA process, DOD identified that the proposed 
expansion would impact about 123,000 ac (49,777 ha) of desert tortoise 
habitat, of which, about 83,000 ac (33,589 ha) is in designated 
critical habitat and within the Superior-Cronese DWMA (Charis 2005, p. 
ES-9). Of the four known populations of Lane Mountain milk-vetch, the 
expansion and operation of the NTC would not impact the 1,283 ac (519 
ha) NASA-Goldstone population, but would impact 66 percent of the 5,499 
ac (2,225 ha) Brinkman Wash-Montana Mine population and 20.25 percent 
of the 4,796 ac (1,941 ha) Paradise Valley population (U.S. Fish and 
Wildlife Service 2004, pp. 24, 53). The 9,775 ac (3,956 ha) Coolgardie 
Mesa population is located outside the Fort Irwin boundary.
    To help offset the loss of habitat of the desert tortoise and Lane 
Mountain milk-vetch, the Army established two conservation areas for 
the Lane Mountain milk-vetch totaling 6,770 ac (2,740 ha) (Charis 2005, 
pp. 4-21 and 4-22); acquired private lands in the Fremont-Kramer and 
Superior-Cronese DWMAs (Fort Irwin 2003, pp. 2-31); and purchased fee 
land and associated assets and improvements associated with the 26,314 
ac (10,649 ha) Harper Dry Lake grazing allotment and retired cattle 
grazing on these lands (Fort Irwin 2003 pp. 2-34). The acquired private 
lands in the Fremont-Kramer and Superior-Cronese DWMAs (see Map 2) and 
the grazing allotment comprise 8.2 and 0.5 percent of the range of the 
Mohave ground squirrel, respectively, whereas the expansion area 
comprises 75,300 ac (30,473 ha) or 1.4 percent of the range of the 
Mohave ground squirrel and the NTC including the expansion area within 
the range of the Mohave ground squirrel comprises 435,978 ac (176,435 
ha) or 8.2 percent of the range of the Mohave ground squirrel (see 
Factor A, ``Military Operations''). When the total area of the acquired 
mitigation lands is compared to the total area of expansion lands, the 
mitigation ratio of

[[Page 62249]]

acquired lands to expansion lands is about 5.8:1.
    The DOD must comply with the Sikes Act and its implementing 
regulations. This law requires the DOD to develop cooperative plans for 
conservation and rehabilitation programs for natural resources on 
military bases and to establish outdoor recreation facilities. Each 
base prepares an Integrated Natural Resources Management Plan (INRMP) 
that provides for fish and wildlife habitat improvements or 
modifications; range rehabilitation where necessary to support 
wildlife; control of OHV traffic; and specific habitat improvement 
projects and related activities and adequate protection for species of 
fish, wildlife, and plants considered threatened or endangered.
    Fort Irwin prepared an INRMP in 2006 that included conservation, 
protection, and management actions for the Mohave ground squirrel. The 
Fort Irwin INRMP recognized the expansion would adversely affect the 
Mohave ground squirrel (Fort Irwin 2006, pp. 135-136) and proposed 
measures in addition to the mitigation measures in the Fort Irwin 
Expansion FEIS. Some of these measures included retiring a grazing 
allotment near Harper Dry Lake in the central portion of the range of 
the Mohave ground squirrel; continuing research on Mohave ground 
squirrel populations at Fort Irwin and the Goldstone Complex, an area 
within Fort Irwin used by NASA and protected from military activities; 
and surveying for the Mohave ground squirrel in the east important 
population area (Fort Irwin 2006, pp. 136-146).
    NAWS is currently revising its INRMP. Its current INRMP states that 
its objectives for the Mohave ground squirrel include ``maintain[ing] 
viable populations'' and ``minimize[ing] impacts and protect[ing] known 
and potential endangered and sensitive species habitats to the maximum 
extent practicable'' (NAWS 2000, pp. 126-127).
    The Air Force completed its INRMP for EAFB in 2008. Based on this 
document, the Air Force is continuing its implementation of surveys for 
the Mohave ground squirrel and implementing specific management 
measures to minimize or eliminate impacts to Mohave ground squirrel 
habitat from ongoing military operations on the base (EAFB 2008a, pp. 
73-76). Also, conservation measures for the federally threatened desert 
tortoise and its designated critical habitat included in the INRMP will 
benefit the Mohave ground squirrel.

Environmental Protection Agency

    The Clean Air Act of 1970 (42 U.S.C. 7401 et seq.) directs the EPA 
to develop and enforce regulations to protect the general public from 
exposure to airborne contaminants that are known to be hazardous to 
human health. In 2007, the U.S. Supreme Court ruled that gases that 
cause global climate change are pollutants under the Clean Air Act, and 
the EPA has the authority to regulate carbon dioxide and other heat-
trapping gases (Massachusetts et al. v. EPA 2007 [Case No. 05-1120]). 
EPA policies to implement the Clean Air Act in addressing climate 
change caused by greenhouse gas emissions are still evolving. However, 
our status review did not reveal information that indicates that 
climate change is a significant threat to the Mohave ground squirrel 
throughout its range (see Factor A).

Other Federal Agencies

    The USFS and NPS have management authority for less than 2 percent 
of the habitat of the Mohave ground squirrel. For the USFS, these lands 
are within Federal wilderness areas on the east side of the Sierra 
Nevada. For the NPS, these lands are within Death Valley National Park. 
Under the Wilderness Act of 1964 (16 U.S.C. 1131-1136), motorized 
activities, including motorized travel, energy development, mining, and 
other mechanized activities, are prohibited. Although grazing may be 
permitted in Federal wilderness areas, the USFS does not permit grazing 
in the Owens Peak and Sacatar Trail wilderness areas, which are within 
the range of the Mohave ground squirrel.
    The amount of USFS lands within the range of the Mohave ground 
squirrel is very small, about 4,400 ac (1,781 ha) or 0.08 percent, and 
occurs at the west and northwest edge of the species' range. A strip of 
about 44,026 ac (17,824 ha), which is less than 1 percent of the range 
of the Mohave ground squirrel, occurs on NPS land along the northeast 
edge of the range of the species.
Summary of Factor D
    Several laws and regulations, including CEQA, CESA, FLPMA, Sikes 
Act, and NEPA, provide varying levels and aspects of protection of or 
beneficial measures for the Mohave ground squirrel and its habitat at 
the local, State, and Federal level. Many of these regulatory 
mechanisms also encourage habitat protection for the Mohave ground 
squirrel and provide tools to implement these habitat protections. 
Although no single law or regulation provides overall protection of the 
Mohave ground squirrel and its habitat throughout its range, we find 
that, cumulatively, when implemented, existing regulations provide for 
the long-term survival of the species. Our assessment of threats based 
on the best available scientific and commercial information regarding 
the loss and degradation of the range or habitat of the Mohave ground 
squirrel under Factor A, and fragmentation and mortality as discussed 
under Factor E lead us to conclude that the inadequacy of existing 
regulatory mechanisms is not a threat to the Mohave ground squirrel. 
Therefore, based on our review of the best available scientific and 
commercial information, we conclude that the Mohave ground squirrel is 
not currently threatened by inadequate regulatory mechanisms throughout 
its range, nor do we anticipate inadequate regulatory mechanisms posing 
a threat in the future.

Factor E: Other Natural or Manmade Factors Affecting the Continued 
Existence of the Species

Direct Mortality
    As discussed in Factor A, several actions/stressors may result in 
mortality of the Mohave ground squirrel. Heavy equipment used in the 
construction of urban and rural development, roads, energy facilities, 
agricultural areas, and mines may crush Mohave ground squirrels above 
ground and in their burrows. The intensive use of vehicles in OHV 
management areas and wheeled and tracked vehicles used off road in 
military operations may have similar impacts. Although we recognize 
that mortality of Mohave ground squirrels from these sources occurs, we 
found few documented reports of Mohave ground squirrels being run over 
by vehicles (Threloff 2007, in litt.) or heavy equipment and no reports 
of them being killed in their burrows. The level of mortality is likely 
a function of a number of complex variables including squirrel density, 
habitat quality, time of year, and type and intensity of human 
activity. Mortality is probably highest in areas of preferred habitat 
where heavy equipment is used, habitat is cleared, and human activity 
is high (e.g., urban development, road construction), as the entire 
area is graded and replaced with man-made structures. Roads may be 
another important source of direct mortality, and depending on factors 
such as location, road width, and traffic rates, roads could result in 
reduced Mohave ground squirrel abundance. However, Glista et al. (2008, 
p. 80) found that during a 17-month study in Indiana, only 3 percent of 
the animals

[[Page 62250]]

killed on roads were mammals. Garland and Bradley (1984, p. 52) found 
no mortality within their study area during an 11-month study on the 
effects of a highway on Mojave Desert rodent populations, including the 
round-tailed ground squirrel. Also, Rosa and Bissonette (2008, p. 565) 
found that in a desert community in southern Utah, roads (specifically 
I-15) did not appear to affect small mammal abundance or diversity near 
or away from roads and concluded that the abundance and diversity of 
small mammals respond more markedly to habitat quality and complexity 
than to the presence of roads. Thus, road mortality does not appear to 
affect the abundance of small mammals, such as the Mohave ground 
squirrel.
    In summary, although direct mortality has likely occurred and will 
continue to occur during construction, in high-use OHV areas, during 
military operations, and on highways, there is no evidence that 
mortality is having an impact on the Mohave ground squirrel or is a 
significant threat to the species. Although road mortality has not been 
studied for the Mohave ground squirrel, research on other species of 
small mammals has not found a relationship between road mortality and 
abundance. Therefore, we conclude that direct mortality is not 
currently a significant threat to the Mohave ground squirrel, nor do we 
anticipate it posing a threat in the future.
Habitat Fragmentation
    As discussed in Factor A, urban and rural development, OHV 
recreational use, transportation infrastructure, military operations, 
energy development, and agriculture may cause or contribute to habitat 
fragmentation. Habitat fragmentation is the separation or splitting 
apart of previously contiguous, functional habitat components of a 
species. Habitat fragmentation can result from direct habitat loss that 
leaves the remaining habitat in noncontiguous patches, or from the 
alteration of habitat areas that render the altered patches unusable to 
a species (i.e., functional habitat loss). Alterations that can result 
in functional habitat loss include: disturbances that change a 
habitat's successional state or remove one or more habitat functions, 
creation of physical barriers that preclude the use of otherwise 
suitable areas, and activities that prevent animals from using suitable 
habitat patches due to behavioral avoidance. When a habitat patch 
becomes isolated, the animal population is also isolated, and gene flow 
with other populations is reduced or eliminated. A small, isolated 
population may not be as able to survive environmental changes or 
stochastic events; may experience changes in gene frequencies due to 
genetic drift, diminished genetic diversity, and/or effects due to 
inbreeding (i.e., inbreeding depression) (Lande 1995, p. 786); and may 
eventually be extirpated. Animals from nearby populations are unable to 
re-establish the lost population because the habitat is not accessible. 
The effects of fragmentation on a species such as the Mohave ground 
squirrel depend on a complex array of factors such as patch size, type 
of barrier, distance between populations, and condition of habitat 
between patches.
    Most urban and rural development in the western Mojave Desert has 
occurred in the southernmost portion of the range of the Mohave ground 
squirrel. This development has destroyed habitat, leaving patches of 
various quality and size of Mohave ground squirrel habitat interspersed 
among developed areas. In the southernmost portion of the range, 
habitat has been severely fragmented, and we assume that any remaining 
small patches of Mohave ground squirrel habitat in the southernmost 
portion of the range that are surrounded by large areas of urban 
development no longer support Mohave ground squirrels. However, none of 
the eight important population areas is located in the southernmost 
portion of the range, and all eight are at least in part interconnected 
by Federal land, where urban development is heavily restricted. Also, 
urbanization outside the southernmost portion of the range is limited 
to only a few areas and is not a major barrier.
    Vehicular recreation, specifically in OHV management and high-use 
areas, may cause fragmentation. As mentioned in Factor A, impacts in 
OHV areas include disturbance of soils and destruction of shrubs, both 
of which combine to reduce the number of native spring annual plants, 
which in turn reduces habitat suitability for the Mohave ground 
squirrel. We presume these areas are extensively degraded and provide 
little value to supporting populations of Mohave ground squirrels now, 
or in the future. However, some habitat remains within these areas as 
indicated by the occurrence of Mohave ground squirrels in the Dove 
Springs Open Area. The distance between squirrel populations, the 
distance between habitat patches that may support squirrels, and the 
condition of the area between patches are likely primary influences on 
the ability of squirrels to move through an OHV management area. 
Therefore, the larger management areas (e.g., Spangler Hills) are more 
likely to be major barriers than the smaller ones (e.g., Dove Springs). 
Regardless, there are relatively few intensively used OHV areas within 
the range of the Mohave ground squirrel, and with the possible 
exception of Spangler Hills, they do not limit movement between the 
eight important population areas (maps 1 and 2). Spangler Hills, the 
largest management area, lies between two of the important population 
areas and likely limits movement between them. However, these two 
population areas, as well as others, remain connected to the west and 
south by BLM lands that are closed to cross-country OHV use, including 
a portion of the MGSCA, and to the east by a combination of BLM and 
NAWS lands. Therefore, we conclude that OHV use does not constitute a 
major barrier to Mohave ground squirrel movement.
    Transportation infrastructure may cause or contribute to habitat 
fragmentation when linear developments (roads) or transportation 
corridors substantially reduce or prevent the movement of a species 
from one location to another. Negative effects of corridors include 
mortality of animals along roadways (Rosen and Lowe 1994, as cited in 
Lovich and Bainbridge 1998, p. 331; Boarman and Sazaki 1996, as cited 
in Lovich and Bainbridge 1998, p. 331) and restriction of movements and 
gene flow (Nicholson 1978, as cited in Lovich and Bainbridge 1999, p. 
313).
    Radio-collared Mohave ground squirrels are known to have crossed 
four-lane, divided highways (Leitner pers. comm., as cited in Defenders 
of Wildlife and Stewart 2005, p. 22). However, highways with high 
traffic volume and multiple lanes (e.g., I-15 and SR-14) (see Map 1) 
may reduce movements of Mohave ground squirrels from one side to the 
other. Some stretches of multi-lane highways (I-15 and portions of SR-
14) that cross areas within the range of the Mohave ground squirrel 
have, on average, over 36,000 vehicles pass over them daily, while 
other multi-lane highways (rural parts of SR-14) and the smaller, two-
lane highways within the species' range have roughly 3,100 to 7,800 
vehicles per day, on average (Caltrans 2010c, pp. 33-34, 36-37). We 
assume that the increased level of vehicle traffic on the portions of 
the multi-lane highways, along with the greater number of physical 
hindrances that may result from multiple lanes, is more likely to serve 
as a barrier than the smaller, less-traveled two-lane highways. In 
these cases, squirrels may be limited to crossing under bridges and 
culverts.

[[Page 62251]]

    Depending on how roads are constructed, they may serve as physical 
hindrances to the movement of Mohave ground squirrels. For example, a 
road with a roadway divider (e.g., K-rail) may contribute to making a 
roadway a physically impassible barrier for Mohave ground squirrels. 
Although there are no studies on the impacts of roads specific to the 
Mohave ground squirrel, studies on other small mammals, including other 
species of squirrels in desert habitat, have found the following: roads 
may have a neutral or slightly positive effect on small mammals 
species; roads do not appear to affect small mammal abundance or 
diversity near or away from them; and the abundance and diversity of 
small mammals responds more markedly to habitat quality and complexity 
than to the presence of roads (Rosa and Bissonette 2007, p. 565). In 
addition, bridges and culverts, especially those with larger-sized 
openings, may allow Mohave ground squirrels to cross under roads 
(Painter and Ingraldi 2007, p. 17). Although it is not known whether 
the openings under such structures are used regularly by the Mohave 
ground squirrel, it is likely that undercrossings with natural 
substrates created by larger culverts and bridges are used to some 
extent.
    Although the amount of contact needed to maintain population 
connectivity of Mohave ground squirrels is not known, Mills and 
Allendorf (1996, p. 1517) suggested that if 1 to 10 individuals per 
generation successfully cross, that level of movement is likely 
sufficient to maintain the connection between populations, provided the 
overall population is of sufficient size. Thus, a potential barrier 
would have to almost entirely eliminate Mohave ground squirrel movement 
throughout its length and at all times for it to be a complete barrier. 
In addition, Bell et al. (2006, pp. 18, 39, and 40) found low genetic 
diversity throughout the range of the species, suggesting that gene 
flow occurs throughout the range and roads are not complete barriers to 
Mohave ground squirrel movement.
    Military operations, such as intense ground forces training 
activities on the NTC portion of Fort Irwin, may contribute to 
fragmentation of Mohave ground squirrel habitat. The recent expansion 
at Fort Irwin will bring the impacts of ground forces training 
activities into part of the Coolgardie Mesa-Superior Valley important 
population area identified by Leitner (2008, p. 1) (see Factor A, 
``Military Operations''). Ground forces training in the expansion area 
may restrict Mohave ground squirrel populations to the south from 
accessing populations in the Goldstone Complex (see Map 1), thus 
isolating the Goldstone area (Defenders of Wildlife and Stewart 2005, 
p. 21). However, access for Mohave ground squirrels between the 
Goldstone Complex and other areas is available to the west and north 
through NAWS. Access from Coolgardie Mesa and Superior Valley to the 
west and south is available through the Superior-Cronese DWMA and NAWS 
(see Map 2). Although ground forces training will impact part of the 
Coolgardie Mesa-Superior Valley important population area, access to 
this area from the north, west, and south would not be disrupted by 
ground forces training.
    Several renewable energy projects have been constructed in the 
range of the Mohave ground squirrel; these projects encompass about 2.2 
percent of the squirrel's range. Additional renewable energy projects 
have been proposed in the western Mojave Desert, and depending on their 
size and location, they could reduce the ability of the Mohave ground 
squirrel to move between populations.
    We know that future renewable energy projects on Federal lands, 
which make up about two-thirds of the range of the Mohave ground 
squirrel, are likely to be limited. Renewable energy projects proposed 
on DOD lands make up less than 0.01 percent of the range of the Mohave 
ground squirrel. The BLM has received applications that, if all were 
built, would encompass an additional 2.5 percent of the range of the 
Mohave ground squirrel. However, this is an overestimate because many 
of these proposals overlap and many would be constructed in areas that 
are not suitable habitat for squirrels. Also, energy development within 
the DWMAs or the MGSCA would be extremely limited because of the 1 
percent cap on development and the 5:1 mitigation ratio. The mitigation 
in these areas and the 1:1 mitigation the BLM requires outside of these 
areas means that, although Mohave ground squirrel habitat may be lost, 
habitat would be acquired to add to the large blocks of habitat for the 
squirrel in the DWMAs and MGSCA or enhanced to increase the habitat 
value of the DWMAs and MGSCA. In addition, solar projects on BLM land 
may be more likely to occur in one of the four proposed SEZs, which are 
all outside the range of the squirrel. Most of the current and proposed 
wind energy projects are located along the western edge of the range of 
the Mohave ground squirrel, and many will be situated on ridges and 
hilltops, which are not the preferred habitat of the squirrel. 
Geothermal energy is available in only two areas within the range of 
the squirrel, and few new geothermal projects have been proposed. Thus, 
with only a few renewable energy proposals on DOD land and limited 
development in the MGSCA and DWMAs, connectivity will not be 
significantly degraded.
    On non-Federal land, which comprises about one-third of the range 
of the Mohave ground squirrel, several solar and wind energy projects 
have been proposed that would encompass about 1.2 percent of the range 
of the squirrel. However, many of these projects are on lands 
previously converted to agriculture or are along the western edge of 
the Mohave ground squirrel's range on ridges and hilltops, which is not 
preferred habitat. Based on the best scientific and commercial 
information available on current management designations, development 
limitations, and required mitigation, we conclude that fragmentation of 
Mohave ground squirrel habitat is not likely to occur from energy 
development.
    Agricultural development in the western Mojave Desert is 
concentrated in the western Antelope Valley, on the north side of the 
San Gabriel Mountains, and from the Mojave River Valley to the Lucerne 
Valley. New agricultural development is limited by the availability and 
cost of water to produce crops. We recognize that past agricultural 
development may have contributed to fragmentation of Mohave ground 
squirrel habitat (see Factor A, ``Agriculture'') and that agriculture 
in combination with other activities fragmented the habitat of the 
Mohave ground squirrel in the Mojave River and Lucerne Valleys. 
However, we do not believe that agriculture constitutes an absolute 
barrier to squirrel movement because habitat requirements for 
dispersing or moving through an area are likely very different than for 
those needed for long-term occupancy. Mohave ground squirrels are known 
to forage along the edges of alfalfa fields (Hoyt 1972, p. 10) and are 
therefore likely able to disperse through such fields.
    The BLM and DOD have taken actions to reduce the impact of habitat 
fragmentation on Mohave ground squirrels on Federal lands. The BLM 
recently designated the MGSCA as a WHMA, two DWMAs as ACECs, and 
expanded the size of the DTNA, all of which are within the range of the 
Mohave ground squirrel (see Map 2). The DOD bases have ``off-limits'' 
areas in Mohave ground squirrel habitat, which reduce or eliminate 
ground disturbance from military activities. Under the Sikes Act, the 
DOD bases are

[[Page 62252]]

obligated to develop cooperative management plans that reflect the 
mutual agreement of the CDFG ``concerning conservation, protection, and 
management of fish and wildlife resources,'' which includes the Mohave 
ground squirrel (see Factor D). The locations of these designated and 
``off-limits'' areas form a contiguous area from the northern portion 
of the range of the Mohave ground squirrel to the southern portion. The 
MGSCA is contiguous with the NAWS and the Fremont-Kramer DWMA, which 
connects with the DTNA, EAFB, the Superior-Cronese DWMA, and the 
Goldstone Complex (BLM et al. 2005, Map 2-1) (see Map 2). Therefore, at 
a landscape scale, the major Federal land management agencies have 
identified large, contiguous blocks of habitat from the northern to the 
southern portion of the range with management prescriptions to help 
conserve the Mohave ground squirrel (see Map 2 and Table 1).
    On private lands, we have no information about any landscape-scale 
plan that considers the Mohave ground squirrel (e.g., NCCP Plan). 
Absent such a plan, private lands within the range of the Mohave ground 
squirrel will likely continue to be developed on a case-by-case basis 
in the future. Most of the development will likely occur near existing 
urban areas in the southernmost portion of the range of the Mohave 
ground squirrel, an area which has already been heavily fragmented. 
However, none of the eight important population areas are located in 
the southernmost portion of the range, and all eight are at least in 
part interconnected by Federal land, where development is limited. 
Urbanization outside the southernmost portion of the range is limited 
to only a few areas and is not a major barrier.
    Future development on BLM lands is directed by the WEMO Plan, which 
limits development within the MGSCA and the DWMAs to 1 percent. The 
three DOD bases have not identified plans to increase their boundaries 
for future military missions. Rather, the DOD recently identified a 
growing conflict between implementing their military missions and 
incompatible residential/commercial development adjacent to their 
boundaries. These areas are within the range of the Mohave ground 
squirrel and most include native desert plant communities used by 
Mohave ground squirrels. Because much of the land on the DOD bases is 
not developed and not expected to be developed in the future, and the 
military installations' INRMPs have provisions to manage for Mohave 
ground squirrel habitat, establishing land buffers will help connect 
the Mohave ground squirrel habitat on the military installations with 
the DWMAs and MGSCA and increase the area being managed, in part, for 
the Mohave ground squirrel. This activity is another means of ensuring 
connectivity among the northern, central, and southern portions of the 
range of the Mohave ground squirrel and reducing the likelihood of 
fragmentation in the future.
    In summary, severe fragmentation as a result of urban and rural 
development has occurred in the southernmost portion of the Mohave 
ground squirrel's range, and movement of the species in that area is 
greatly diminished or has been eliminated. However, urban and rural 
development in the rest of the range has occurred in only a few areas 
and has been more limited in extent. Other activities that may result 
in habitat fragmentation (e.g., OHV recreational use, transportation 
infrastructure, military operations, and energy development) affect 
smaller areas within the range of the Mohave ground squirrel and do not 
constitute major barriers to movement, especially between the eight 
important population areas, all of which are at least in part 
interconnected by Federal land where development that would be a 
barrier to movement is not likely to occur. The ability of squirrels to 
move between populations is further indicated by recent genetic 
research that found low genetic diversity throughout the range of the 
species, which could suggest that gene flow occurs throughout the range 
(Bell et al. 2006, pp. 18, 39, 40). We therefore conclude that habitat 
fragmentation is currently not a threat to the Mohave ground squirrel, 
nor do we anticipate it posing a threat in the future.
Summary of Factor E
    Although direct mortality has likely occurred and will continue to 
occur during construction, in high-use OHV areas, during military 
operations, and on highways, there is no evidence that mortality is 
having an impact on the Mohave ground squirrel or is a significant 
threat to the species. Although road mortality has not been studied for 
the Mohave ground squirrel, research on other species of small mammals 
has not found a relationship between road mortality and abundance.
    Severe habitat fragmentation as a result of urban and rural 
development has occurred in the southernmost portion of the range of 
the Mohave ground squirrel and will likely continue to occur in that 
area. However, large, contiguous tracts of Federal land occur 
throughout the rest of the range of the Mohave ground squirrel, which 
will largely remain undeveloped. These lands support key Mohave ground 
squirrel population areas, including the eight important population 
areas, and provide connectivity throughout much of the range of the 
Mohave ground squirrel, both among these important population areas and 
from the northern portion through the central and southern portions of 
the squirrel's range. This connectivity helps ensure exchange of 
genetic material among the populations of Mohave ground squirrels and 
prevents the deleterious effects of small population dynamics such as 
inbreeding depression. Renewable energy projects are proposed for BLM 
land, but these will likely be very limited in the MGSCA and DWMAs in 
which development of all types is limited to 1 percent of the areas. 
Much of the range of the Mohave ground squirrel has not been developed, 
is not proposed for development at this time, or cannot be developed 
because of restrictions imposed by the BLM and DOD.
    Therefore, based on our review of the best available scientific and 
commercial information, we conclude that the Mohave ground squirrel is 
not currently threatened by other natural or manmade factors throughout 
its range, nor do we anticipate other natural or manmade factors posing 
a threat in the future.

Finding

    As required by the Act, we considered the five factors in assessing 
whether the Mohave ground squirrel is threatened or endangered 
throughout all or a significant portion of its range. We have assessed 
the best scientific and commercial information available regarding 
threats faced by the Mohave ground squirrel. We have reviewed the 
petition, scientific literature, information available in our files, 
and all information submitted to us following our 90-day petition 
finding (75 FR 22063, April 27, 2010). We also consulted with 
recognized Mohave ground squirrel experts, Federal and State land 
managers, and local governments to assess potential threats to the 
habitat and range of the species relative to current and planned land 
uses and occurrences of the species.
    We analyzed the potential threats to the Mohave ground squirrel 
including: Habitat loss and habitat degradation from urban and rural 
development, OHV recreational use, transportation infrastructure, 
military operations, energy development, livestock grazing, 
agriculture, mining, and climate change; predation by native species 
and

[[Page 62253]]

domestic dogs and cats; the inadequacy of regulatory mechanisms to 
control land use and development on private, State, and Federal lands; 
direct mortality; and habitat fragmentation. We found that the Mohave 
ground squirrel continues to be present throughout a large portion of 
its historical and current range.
    Land ownership within the range of the Mohave ground squirrel is 
about one-third private land, one-third DOD land, and one-third BLM 
land. While much of the private land in the southernmost portion of the 
range of the Mohave ground squirrel has been developed or used for 
agriculture, little of the squirrel's range has been developed in the 
central and northern portions of its range where most is under Federal 
jurisdiction and is not subject to development.
    Sources of threats on non-Federal lands include urban and rural 
development, transportation infrastructure, renewable energy, 
agriculture, and mining. We estimate that current and future 
development will comprise about 9-10 percent of the range of the Mohave 
ground squirrel, with most occurring in the incorporated areas. 
Although there is no information specific to the Mohave ground 
squirrel, roads are known in some cases to affect species and their 
habitat beyond the loss of habitat from construction of the road 
itself. As a worst case, we calculated a road-effect zone of about 0.7 
percent of the range for the construction of a new major highway and 
the expansion of two existing major highways. However, research 
indicates that the effects of roads on small mammals in the desert are 
neutral to slightly positive; thus, there may be no negative road-
effect zone for the Mohave ground squirrel. Several renewable energy 
projects have been proposed on private land, which would encompass 
about 1.2 percent of the Mohave ground squirrel's range, but many of 
these are proposed for land that has already been converted to 
agriculture. Although we estimate that about 1 percent of the range of 
the Mohave ground squirrel has been converted to agriculture, because 
of increasing costs for water and economic incentives to use this land 
for other purposes, agricultural lands are being converted to urban or 
rural development. There are few large mines on private land in the 
range of the Mohave ground squirrel.
    On military lands, the impacts to the Mohave ground squirrel are 
mainly from the training of ground forces at the NTC along the eastern 
portion of the species' range. EAFB and NAWS conduct aircraft and 
weapons testing, which leaves most of the area and habitat on these two 
large bases ``off limits'' to ground forces operations. The Goldstone 
Complex is also off limits to such operations. There is limited 
development at the small cantonment area at each military base, OHV use 
is restricted to designated areas that total about 0.2 percent of the 
range of the Mohave ground squirrel, and two military bases have 
announced plans to construct renewable energy projects that could 
impact about 0.3 percent of the range of the Mohave ground squirrel. 
Mining is prohibited on military land.
    Recently, the BLM has undertaken several conservation measures 
specific to the Mohave ground squirrel and its habitat or measures that 
benefit the species on its lands. The BLM designated the Fremont-Kramer 
and Superior-Cronese DWMAs as ACECs, increased the size of the DTNA and 
Rand ACEC, and established the MGSCA. These designations place 
additional restrictions on land use and require the BLM to manage these 
lands in part for Mohave ground squirrel habitat. One such restriction 
is a 1 percent cap on total new development within the MGSCA and DWMAs 
under the WEMO Plan with the requirement for 5:1 mitigation. On BLM 
land, cross-country OHV use is limited to a few specific areas, and the 
number of open roads and trails within the range of the Mohave ground 
squirrel has been reduced. The BLM is restoring habitat in areas with 
closed routes, signing open and closed routes, increasing enforcement 
of route designations, and implementing a monitoring plan to determine 
compliance with route closures and to identify whether any new illegal 
routes are being created. Future energy development is restricted or 
limited in its location and areal extent in much of the range of the 
Mohave ground squirrel. The BLM's 1 percent cap on total new 
development within the MGSCA and DWMAs, including energy projects, 
limits the impacts of proposed or future projects in much of the range 
of the Mohave ground squirrel.
    Livestock grazing on BLM land has been reduced with the BLM's 
recent implementation of public land health standards and guidelines 
for grazing. The BLM has implemented a 33 percent reduction in the area 
authorized for grazing in the range of the Mohave ground squirrel, 
eliminated ephemeral grazing for cattle in the DWMAs, eliminated sheep 
grazing in most of the DWMAs, excluded cattle grazing in the spring in 
DWMAs in years when annual plant productivity is low, excluded cattle 
grazing on NAWS, and authorized the ability of permittees to 
voluntarily relinquish cattle and sheep allotments. Over time, these 
changes are likely to provide increased foraging opportunities for the 
Mohave ground squirrel and reduce the overall amount of time that 
livestock spend within these areas, thus reducing impacts to soils, 
vegetation, and dietary overlap.
    Potential threats associated with climate change are a concern, but 
we do not have evidence to conclude that the threats rise to the level 
of potentially threatening the Mohave ground squirrel within the 
foreseeable future.
    Overall, we estimate that in the next 20-30 years about one-third 
of the range of the Mohave ground squirrel could potentially be lost. 
However, because of a general lack of information on the species and 
uncertainty over future development we based this estimate on a series 
of worst-case assumptions (e.g., we double-counted impacts, assumed 
impacts existed or were worse than the available information indicated, 
assumed all habitat within a project boundary would be lost), and we 
expect that the actual loss during this timeframe will be much less. In 
addition, we did not include the mitigation for the Mohave ground 
squirrel that would be implemented for project implementation. Even if 
the worst case occurs, we expect that most of the remaining area will 
remain relatively undisturbed and in the same condition as it is today. 
More than 80 percent of the remaining land is Federal, much of which 
(e.g., EAFB, NAWS, Goldstone Complex, DWMAs, and MGSCA) is managed, at 
least in part, for the Mohave ground squirrel and its habitat. Of 
particular importance to the status of the Mohave ground squirrel, much 
of the remaining lands are contiguous and provide connectivity from the 
northern end of the range to well south of SR-58 in the southern 
portion of the range. More importantly, these lands contain most or all 
the habitat within the eight important population areas and include 
habitat that provides for connectivity among the eight areas. 
Therefore, we conclude that the present or threatened destruction, 
modification, or curtailment of the habitat or range of the Mohave 
ground squirrel is not a significant threat to this species now or in 
the foreseeable future.
    We found no information that over-collection or overutilization for 
commercial, recreational, scientific, or educational purposes is a 
threat or will become a threat to the species in the future. Therefore, 
we conclude that overutilization for commercial, recreational, 
scientific, or educational purposes does not threaten the Mohave

[[Page 62254]]

ground squirrel now or in the foreseeable future.
    We also found no evidence suggesting that disease is affecting the 
Mohave ground squirrel, and therefore, conclude that disease does not 
threaten the Mohave ground squirrel. Similarly, we found no information 
suggesting that predation by domestic dogs or cats is affecting the 
Mohave ground squirrel. Information on the rate of predation by a 
native predator (coyote) was inferred in one study, but it did not show 
this rate to be a threat to the Mohave ground squirrel. Although the 
number of common ravens in the western Mojave Desert has increased 
substantially in the past few decades, we found no information 
suggesting that predation by the common raven on the Mohave ground 
squirrel has increased or is adversely affecting the squirrel. 
Therefore, we conclude that disease or predation are not significant 
threats to the Mohave ground squirrel now or in the foreseeable future.
    The Mohave ground squirrel is listed as threatened by the State of 
California under the CESA. There are other regulatory mechanisms in 
place, such as CEQA, FLPMA, and Sikes Act that, when implemented, 
provide protections from threats to the Mohave ground squirrel on 
Federal, State, and private land. On Federal lands, agencies such as 
the BLM and DOD have implemented actions under these laws that provide 
for the conservation of the Mohave ground squirrel on much of the lands 
that they manage. We conclude the inadequacy of regulatory mechanisms 
is not a significant threat to the Mohave ground squirrel now or in the 
foreseeable future.
    We considered direct mortality as a potential threat, and although 
direct mortality has likely occurred and will continue to occur during 
construction, in high-use OHV areas, during military operations, and on 
roads, there is no evidence that mortality is having an impact on the 
Mohave ground squirrel or is a significant threat to the species. 
Although road mortality has not been studied for the Mohave ground 
squirrel, research on other species of small mammals has not found a 
relationship between road mortality and abundance.
    Severe habitat fragmentation as a result of urban and rural 
development has occurred in the southernmost portion of the range of 
the Mohave ground squirrel and will likely continue to occur in that 
area. However, large, contiguous tracts of Federal land occur 
throughout the rest of the range of the Mohave ground squirrel, which 
will largely remain undeveloped. These lands support many Mohave ground 
squirrel population areas, including the eight important population 
areas, and provide connectivity throughout much of the range of the 
Mohave ground squirrel both among these important population areas and 
from the northern portion through the central and southern portions of 
the squirrel's range. This connectivity helps ensure exchange of 
genetic material among the populations of Mohave ground squirrels and 
prevents the deleterious effects of small population dynamics such as 
inbreeding depression. Renewable energy projects are proposed for BLM 
land, but these will likely be very limited in the MGSCA and DWMAs in 
which development of all types is limited to 1 percent of the areas. 
Much of the range of the Mohave ground squirrel has not been developed, 
is not proposed for development at this time, or cannot be developed 
because of restrictions imposed by the BLM and DOD. We conclude that 
other natural or manmade factors are not significant threats to the 
Mohave ground squirrel now or in the foreseeable future.
    Our review of the best available scientific and commercial 
information pertaining to the five factors, does not support a 
conclusion that there are independent or cumulative threats of 
sufficient imminence, intensity, or magnitude to indicate that the 
Mohave ground squirrel is in danger of extinction (endangered), or 
likely to become endangered within the foreseeable future (threatened), 
throughout its range. Therefore, listing the Mohave ground squirrel as 
endangered or threatened is not warranted at this time.

Distinct Vertebrate Population Segment

    After assessing whether the species is endangered or threatened 
throughout its range, we next consider whether any distinct vertebrate 
populations segment (DPS) exists and meets the definition of endangered 
or is likely to become endangered in the foreseeable future 
(threatened). Under the Service's Policy Regarding the Recognition of 
Distinct Vertebrate Population Segments Under the Endangered Species 
Act (61 FR 4722; February 7, 1996), three elements are considered in 
the decision concerning the establishment and classification of a 
possible DPS. These are applied similarly for additions to or removal 
from the Federal List of Endangered and Threatened Wildlife. These 
elements include:
    (1) The discreteness of a population in relation to the remainder 
of the species to which it belongs;
    (2) The significance of the population segment to the species to 
which it belongs; and
    (3) The population segment's conservation status in relation to the 
Act's standards for listing, delisting, or reclassification (i.e., is 
the population segment endangered or threatened).
    Under the DPS Policy, we must first determine whether the 
population qualifies as a DPS; this requires a finding that the 
population is both: (1) Discrete in relation to the remainder of the 
species to which it belongs; and (2) biologically and ecologically 
significant to the species to which it belongs. If the population meets 
the first two criteria under the DPS policy, we then proceed to the 
third element in the process, which is to evaluate the population 
segment's conservation status in relation to the Act's standards for 
listing as an endangered or threatened species. The DPS evaluation in 
this finding concerns the Mohave ground squirrel that we were 
petitioned to list as threatened or endangered.
Discreteness
    Under the DPS Policy, a population segment of a vertebrate taxon 
may be considered discrete if it satisfies either one of the following 
conditions:
    (1) It is markedly separated from other populations of the same 
taxon as a consequence of physical, physiological, ecological, or 
behavioral factors. Quantitative measures of genetic or morphological 
discontinuity may provide evidence of this separation.
    (2) It is delimited by international governmental boundaries within 
which differences in control of exploitation, management of habitat, 
conservation status, or regulatory mechanisms exist that are 
significant in light of section 4(a)(1)(D) of the Act.
Markedly Separated From Other Populations of the Taxon
    As described previously (see Species Information above), the Mohave 
ground squirrel extends throughout the range except where the habitat 
has been lost due to human activities, primarily along the southern and 
eastern portion of its range. We found no information that any Mohave 
ground squirrel population is markedly separated from other populations 
as a consequence of physical, physiological, ecological, or behavioral 
factors.
    There are no international governmental boundaries associated with 
this species that are significant. The Mohave ground squirrel is found 
wholly within the United States. Because this element is not relevant 
in this case for a finding of discreteness, it

[[Page 62255]]

was not considered in reaching the determination.
    We did not find any information that would indicate any DPS exists. 
Therefore, we determine, based on a review of the best available 
information, that there are no portions of the species' range that meet 
the discreteness criterion of the Service's DPS policy. The DPS policy 
is clear that significance is analyzed only when a population segment 
has been identified as discrete. Because both discreteness and 
significance are required to satisfy the DPS policy, we have determined 
that there are no populations of the Mohave ground squirrel that 
qualify as a DPS under our policy. As a result, no further analysis 
under the DPS policy is necessary.

Significant Portion of the Range Analysis

    Having determined that the Mohave ground squirrel is not in danger 
of extinction or likely to become endangered within the foreseeable 
future throughout all of its range, we must next consider whether there 
are any significant portions of the range where the Mohave ground 
squirrel is in danger of extinction or is likely to become endangered 
in the foreseeable future.
    Decisions by the Ninth Circuit Court of Appeals in Defenders of 
Wildlife v. Norton, 258 F.3d 1136 (2001) and Tucson Herpetological 
Society v. Salazar, 566 F.3d 870 (2009) found that the Act requires the 
Service, in determining whether a species is endangered or threatened 
throughout a significant portion of its range, to consider whether lost 
historical range of a species (as opposed to its current range) 
constitutes a significant portion of the range of that species. While 
this is not our interpretation of the statute, we first address the 
lost historical range before addressing the current range.
Historical Range
    Available information provides no evidence of a significant loss of 
the historical range of the Mohave ground squirrel. Although the 
petition to list the Mohave ground squirrel indicated that the western 
Antelope Valley was no longer part of the species' current range, 
suitable habitat still remains in much of the western Antelope Valley 
and may be connected to habitat currently occupied by the Mohave ground 
squirrel. This information is supported by recent visual observations 
of Mohave ground squirrels in the western Antelope Valley (see ``Range 
and Distribution'' section). Additionally, although areas of natural 
habitat within the range of the Mohave ground squirrel have been lost 
or degraded from human activity (see Factor A), the boundary of the 
current range is larger than reported by Howell in 1938, and may even 
be larger than now defined by the Service, as there have been recent 
sightings beyond the area defined by the Service as the range of the 
Mohave ground squirrel (see ``Range and Distribution'' section).'' 
Therefore, there is no lost historical range of the Mohave ground 
squirrel that could constitute a significant portion of the range of 
the species.
Current Range
    The Act defines ``endangered species'' as any species which is ``in 
danger of extinction throughout all or a significant portion of its 
range,'' and ``threatened species'' as any species which is ``likely to 
become an endangered species within the foreseeable future throughout 
all or a significant portion of its range.'' The definition of species 
is also relevant to this discussion. The Act defines ``species'' as 
follows: ``The term `species' includes any subspecies of fish or 
wildlife or plants, and any distinct population segment [DPS] of any 
species of vertebrate fish or wildlife which interbreeds when mature.'' 
The phrase ``significant portion of its range'' (SPR) is not defined by 
the statute, and we have never addressed in our regulations: (1) The 
consequences of a determination that a species is either endangered or 
likely to become so throughout a significant portion of its range, but 
not throughout all of its range; or (2) what qualifies a portion of a 
range as ``significant.''
    Two recent district court decisions have addressed whether the SPR 
language allows the Service to list or protect less than all members of 
a defined ``species'': Defenders of Wildlife v. Salazar, 729 F. Supp. 
2d 1207 (D. Mont. 2010), concerning the Service's delisting of the 
Northern Rocky Mountain gray wolf (74 FR 15123, Apr. 12, 2009); and 
WildEarth Guardians v. Salazar, 2010 U.S. Dist. LEXIS 105253 (D. Ariz. 
Sept. 30, 2010), concerning the Service's 2008 finding on a petition to 
list the Gunnison's prairie dog (73 FR 6660, Feb. 5, 2008). The Service 
had asserted in both of these determinations that it had authority, in 
effect, to protect only some members of a ``species,'' as defined by 
the Act (i.e., species, subspecies, or DPS), under the Act. Both courts 
ruled that the determinations were arbitrary and capricious on the 
grounds that this approach violated the plain and unambiguous language 
of the Act. The courts concluded that reading the SPR language to allow 
protecting only a portion of a species' range is inconsistent with the 
Act's definition of ``species.'' The courts concluded that once a 
determination is made that a species (i.e., species, subspecies, or 
DPS) meets the definition of ``endangered species'' or ``threatened 
species,'' it must be placed on the list in its entirety and the Act's 
protections applied consistently to all members of that species 
(subject to modification of protections through special rules under 
sections 4(d) and 10(j) of the Act).
    Consistent with that interpretation, and for the purposes of this 
finding, we interpret the phrase ``significant portion of its range'' 
in the Act's definitions of ``endangered species'' and ``threatened 
species'' to provide an independent basis for listing: a species may be 
endangered or threatened throughout all of its range; or a species may 
be endangered or threatened in only a significant portion of its range. 
If a species is in danger of extinction throughout an SPR, it, the 
species, is an ``endangered species.'' The same analysis applies to 
``threatened species.'' Based on this interpretation and supported by 
existing case law, the consequence of finding that a species is 
endangered or threatened in only a significant portion of its range is 
that the entire species shall be listed as endangered or threatened, 
respectively, and the Act's protections shall be applied across the 
species' entire range.
    We conclude, for the purposes of this finding, that interpreting 
the SPR phrase as providing an independent basis for listing is the 
best interpretation of the Act because it is consistent with the 
purposes and the plain meaning of the key definitions of the Act; it 
does not conflict with established past agency practice (i.e., prior to 
the 2007 Solicitor's Opinion), as no consistent, long-term agency 
practice has been established; and it is consistent with the judicial 
opinions that have most closely examined this issue. Having concluded 
that the phrase ``significant portion of its range'' provides an 
independent basis for listing and protecting the entire species, we 
next turn to the meaning of ``significant'' to determine the threshold 
for when such an independent basis for listing exists.
    Although there are potentially many ways to determine whether a 
portion of a species' range is ``significant,'' we conclude, for the 
purposes of this finding, that the significance of the portion of the 
range should be determined based on its biological contribution to the 
conservation of the species. For this reason, we describe the threshold 
for ``significant'' in terms of an increase in the risk of extinction 
for the species. We conclude that a

[[Page 62256]]

biologically based definition of ``significant'' best conforms to the 
purposes of the Act, is consistent with judicial interpretations, and 
best ensures species' conservation. Thus, for the purposes of this 
finding, and as explained further below, a portion of the range of a 
species is ``significant'' if its contribution to the viability of the 
species is so important that without that portion, the species would be 
in danger of extinction.
    We evaluate biological significance based on the principles of 
conservation biology using the concepts of resiliency, redundancy, and 
representation. Resiliency describes the characteristics of a species 
and its habitat that allow it to recover from periodic disturbance. 
Redundancy (having multiple populations distributed across the 
landscape) may be needed to provide a margin of safety for the species 
to withstand catastrophic events. Representation (the range of 
variation found in a species) ensures that the species' adaptive 
capabilities are conserved. Resiliency, redundancy, and representation 
are not independent of each other, and some characteristic of a species 
or area may contribute to all three. For example, distribution across a 
wide variety of habitat types is an indicator of representation, but it 
may also indicate a broad geographic distribution contributing to 
redundancy (decreasing the chance that any one event affects the entire 
species), and the likelihood that some habitat types are less 
susceptible to certain threats, contributing to resiliency (the ability 
of the species to recover from disturbance). None of these concepts is 
intended to be mutually exclusive, and a portion of a species' range 
may be determined to be ``significant'' due to its contributions under 
any one or more of these concepts.
    For the purposes of this finding, we determine if a portion's 
biological contribution is so important that the portion qualifies as 
``significant'' by asking whether without that portion, the resiliency, 
redundancy, or representation of the species would be so impaired that 
the species would have an increased vulnerability to threats to the 
point that the overall species would be in danger of extinction (i.e., 
would be ``endangered''). Conversely, we would not consider the portion 
of the range at issue to be ``significant'' if there is sufficient 
resiliency, redundancy, and representation elsewhere in the species' 
range that the species would not be in danger of extinction throughout 
its range if the population in that portion of the range in question 
became extirpated (extinct locally).
    We recognize that this definition of ``significant'' (a portion of 
the range of a species is ``significant'' if its contribution to the 
viability of the species is so important that without that portion, the 
species would be in danger of extinction) establishes a threshold that 
is relatively high. On the one hand, given that the consequences of 
finding a species to be endangered or threatened in an SPR would be 
listing the species throughout its entire range, it is important to use 
a threshold for ``significant'' that is robust. It would not be 
meaningful or appropriate to establish a very low threshold whereby a 
portion of the range can be considered ``significant'' even if only a 
negligible increase in extinction risk would result from its loss. 
Because nearly any portion of a species' range can be said to 
contribute some increment to a species' viability, use of such a low 
threshold would require us to impose restrictions and expend 
conservation resources disproportionately to conservation benefit: 
listing would be rangewide, even if only a portion of the range of 
minor conservation importance to the species is imperiled. On the other 
hand, it would be inappropriate to establish a threshold for 
``significant'' that is too high. This would be the case if the 
standard were, for example, that a portion of the range can be 
considered ``significant'' only if threats in that portion result in 
the entire species' being currently endangered or threatened. Such a 
high bar would not give the SPR phrase independent meaning, as the 
Ninth Circuit held in Defenders of Wildlife v. Norton, 258 F.3d 1136 
(9th Cir. 2001).
    The definition of ``significant'' used in this finding carefully 
balances these concerns. By setting a relatively high threshold, we 
minimize the degree to which restrictions will be imposed or resources 
expended that do not contribute substantially to species conservation. 
But we have not set the threshold so high that the phrase ``in a 
significant portion of its range'' loses independent meaning. 
Specifically, we have not set the threshold as high as it was under the 
interpretation presented by the Service in the Defenders litigation. 
Under that interpretation, the portion of the range would have to be so 
important that current imperilment there would mean that the species 
would be currently imperiled everywhere. Under the definition of 
``significant'' used in this finding, the portion of the range need not 
rise to such an exceptionally high level of biological significance. 
(We recognize that if the species is imperiled in a portion that rises 
to that level of biological significance, then we should conclude that 
the species is in fact imperiled throughout all of its range, and that 
we would not need to rely on the SPR language for such a listing.) 
Rather, under this interpretation we ask whether the species would be 
endangered everywhere without that portion, i.e., if that portion were 
completely extirpated. In other words, the portion of the range need 
not be so important that even the species being in danger of extinction 
in that portion would be sufficient to cause the species in the 
remainder of the range to be endangered; rather, the complete 
extirpation (in a hypothetical future) of the species in that portion 
would be required to cause the species in the remainder of the range to 
be endangered.
    The range of a species can theoretically be divided into portions 
in an infinite number of ways. However, there is no purpose to 
analyzing portions of the range that have no reasonable potential to be 
significant or to analyzing portions of the range in which there is no 
reasonable potential for the species to be endangered or threatened. To 
identify only those portions that warrant further consideration, we 
determine whether there is substantial information indicating that: (1) 
The portions may be ``significant,'' and (2) the species may be in 
danger of extinction there or likely to become so within the 
foreseeable future. Depending on the biology of the species, its range, 
and the threats it faces, it might be more efficient for us to address 
the significance question first or the status question first. Thus, if 
we determine that a portion of the range is not ``significant,'' we do 
not need to determine whether the species is endangered or threatened 
there; if we determine that the species is not endangered or threatened 
in a portion of its range, we do not need to determine if that portion 
is ``significant.'' In practice, a key part of the determination that a 
species is in danger of extinction in a significant portion of its 
range is whether the threats are geographically concentrated in some 
way. If the threats to the species are essentially uniform throughout 
its range, no portion is likely to warrant further consideration. 
Moreover, if any concentration of threats to the species occurs only in 
portions of the species' range that clearly would not meet the 
biologically based definition of ``significant,'' such portions will 
not warrant further consideration.
    Through our range-wide analysis, we found that there is not one 
individual

[[Page 62257]]

impact that occurs throughout the range of the species, that is, the 
threats are not uniform throughout the species' range, and that some 
areas receive a greater number of impacts, although the magnitude may 
vary. After reviewing the potential threats throughout the range of the 
Mohave ground squirrel, we determine that there may be two portions of 
the squirrel's range that could be considered to have concentrated 
threats for the species there: one area is in the southern portion of 
the range and the other is the central portion of the range where Fort 
Irwin is located. Impacts in the southern portion of the species' range 
include urban and rural development, recreation, transportation 
network, military operations, energy development, livestock grazing, 
agriculture, and mining. In the central portion, the impacts include 
urban and rural development, OHV recreational use, military operations, 
energy development, livestock grazing, and mining. Below, we outline 
the elevated threats found in these portions. We then assess whether 
these portions of the species' range may meet the biologically based 
definition of ``significant,'' that is, whether the contributions of 
these portions of the Mohave ground squirrel's range to the viability 
of the species is so important that without those portions, the species 
would be in danger of extinction.
    Southern Portion of the Range: The impacts of urban and rural 
development and agriculture are concentrated in the southern portion of 
the range of the Mohave ground squirrel. This area is south of the 
Fremont-Kramer DWMA, south of EAFB, and south of SR-138 (see Maps 1 and 
2). This area is the location of much of the urban and rural 
development and agriculture in the western Mojave Desert. Much of the 
western portion of the Antelope Valley south of SR-138, the area south 
of Littlerock and Pearblossom, and the Mojave River Valley have been 
developed for intensive agriculture (USGS 2000. p. 1). In addition, 
most of the human population in the western Mojave Desert is located in 
this area. As mentioned in the ``Urban and Rural Development'' section, 
about 300,000 ac (121,406 ha) south of SR-58, which is about 5.6 
percent of the range of the Mohave ground squirrel, is incorporated 
(BLM 2005a, p. 3-2) and subject to future development. Additional 
acreage has been affected by rural development along the southern 
portion of the range of the Mohave ground squirrel, but data on this 
area are unavailable. More than 39,000 ac (15,700 ha) has been lost to 
agriculture including the Antelope Valley and Mojave River Basin 
(Gustafson 1993, p. 24). The known losses in urban and rural 
development and agriculture are about 6.4 percent of the range of the 
Mohave ground squirrel, but the actual losses would be larger when 
including the unincorporated areas of development. This urban and rural 
development and agriculture are mostly located along the southern edge 
of the range of the Mohave ground squirrel (Map 2). Their locations 
would not inhibit the movement of the Mohave ground squirrel among the 
important population areas.
    Central Portion of the Range: The second area where impacts are 
concentrated is the Fort Irwin NTC, including the expansion area. The 
area is about 435,978 ac (176,435 ha) including the expansion area, or 
about 8.2 percent of the range of the Mohave ground squirrel. However, 
not all of this area is used for ground forces training so the area of 
impact is less. One of the Mohave ground squirrel important population 
areas, the Coolgardie Mesa-Superior Valley core area, is located on 
lands managed by the BLM and Fort Irwin (expansion area and Goldstone 
Complex). Although part of this important population area will be 
subject to ground forces training, part is an off-limits area to these 
impacts (Charis 2005, chapter 4, p. 14), part is located on lands 
managed by the BLM that include an ACEC for the federally endangered 
Lane Mountain milk-vetch (Astragalus jaegerianus), and the desert 
tortoise (BLM et al. 2005, chapter 2, pp. 15, 214-215), and part is in 
the Goldstone Complex which is off-limits to military training. The 
Army has designated areas within the expansion area that combined total 
6,704 ac (2,713 ha) as off-limits ground forces training (Charis 2005, 
chapter 4, pp. 11, 21, 22).
    For this analysis, we will look at the significance question first 
(i.e., whether the concentration of these threats applies to portions 
of the range that are so important to the viability of the species that 
without those portions, the species would be in danger of extinction). 
To do so, we conduct an evaluation of resiliency, redundancy, and 
representation. The terms ``resiliency,'' ``redundancy,'' and 
``representation'' are intended to be indicators of the conservation 
value of portions of the range.
    Resiliency of a species allows the species to recover from periodic 
disturbance. A species will likely be more resilient if large 
populations exist in high-quality habitat that is distributed 
throughout the range of the species in such a way as to capture the 
environmental variability found within the range of the species. A 
portion of the range of a species may make an essential contribution to 
the resiliency of the species if the area is relatively large and 
contains particularly high-quality habitat, or if its location or 
characteristics make it less susceptible to certain threats than other 
portions of the range. When evaluating whether or how a portion of the 
range contributes to resiliency of the species, we evaluate the 
historical value of the portion and how frequently the portion is used 
by the species, if possible. In addition, the portion may contribute to 
resiliency for other reasons--for instance, it may contain an important 
concentration of certain types of habitat that are necessary for the 
species to carry out its life-history functions, such as breeding, 
feeding, migration, dispersal, or wintering.
    Resiliency, as a measure of a portion of the range's contribution 
to the viability of the species, may apply if a portion occurs in an 
environment that is meaningfully different from the rest; that is, 
representing differences to capture the environmental variability 
within the range of the species. We found that there was a large, 
contiguous area with management guidance for the Mohave ground squirrel 
(e.g. the MGSCA, NAWS, Fremont-Kramer DWMA and DTNA, Superior-Cronese 
DWMA, Goldstone Complex, and EAFB) (see Map 2). This area occurs from 
the northern portion through the southern portion of the species' 
range, and represents a variety of latitudes, elevations, rainfall, 
temperatures, soils, and vegetation. Based on a review of the best 
available scientific and commercial information, we find no indication 
that any geographic area is different from the rest of the range of the 
Mohave ground squirrel regarding environmental variability, or that one 
portion of the Mohave ground squirrel's range exhibits ecological or 
environmental characteristics that differ from another portion. 
Therefore, we conclude that the Southern and the Central portions of 
the range of the Mohave ground squirrel, individually and in 
combination, do not provide an essential contribution to the resiliency 
of the species.
    Redundancy of populations may be needed to provide a margin of 
safety for the species to withstand catastrophic events. This does not 
mean that any portion that provides redundancy is necessarily a 
significant portion of the range of a species. The idea is to conserve 
enough areas of the range such that random perturbations in the system 
act on only a few populations.

[[Page 62258]]

Therefore, each area must be examined based on whether that area 
provides an increment of redundancy that is important to the 
conservation of the species.
    Redundancy is a measure to ensure that a species is able to 
withstand catastrophic events. If sufficiently large enough areas of 
the species are conserved, then random events would impact only a small 
portion of the species. Researchers have identified eight important 
population areas where Mohave ground squirrels are known to occur 
consistently (Leitner 2008, pp. 10-12). Mohave ground squirrels are 
also known to occur in many other areas, although less is known about 
those populations. These important areas occur throughout much of the 
range of the Mohave ground squirrel including the southern, central, 
and northern portions of the species' range. There may be more 
important population areas for the Mohave ground squirrel that have not 
been identified because much of the range of the species has not been 
surveyed to determine population location and trend. Based on the best 
available scientific and commercial information, we find that there is 
a large area being managed for the species (see Map 2) and that the 
eight important population areas and other potentially important 
population areas are well distributed across the species' range. Thus, 
there is no portion of the range of the Mohave ground squirrel 
identified as being necessary to conserve the species in case there is 
a catastrophic event. Therefore, we conclude that the Southern and the 
Central portions of the range of the Mohave ground squirrel, 
individually and in combination, do not provide an essential 
contribution to the redundancy of the species.
    Adequate representation ensures that the species' adaptive 
capabilities are conserved. Specifically, the portion should be 
evaluated to see how it contributes to the genetic diversity of the 
species. The loss of genetically based diversity may substantially 
reduce the ability of the species to respond and adapt to future 
environmental changes. A peripheral population may provide an essential 
contribution to representation if there is evidence that it provides 
genetic diversity due to its location on the margin of the species' 
habitat requirements.
    Representation includes the genetic diversity of the species. We 
found that, using mitochondrial DNA (a maternally inherited genetic 
marker), estimates of gene flow among the past few generations were low 
between some populations (Coolgardie Mesa and EAFB) but not others 
(Olancha and Freeman Gulch, Freeman Gulch and EAFB) (Bell 2006, pp. 42-
44). This reduced gene flow may have been caused by the recent drought 
years in the western Mojave Desert or limited movements of female 
Mohave ground squirrels. However, when using nuclear DNA, which is 
inherited from both parents rather than just the mother, the results 
did not show that gene flow was low between populations of Mohave 
ground squirrels. Bell's genetic analysis of long-term levels of gene 
flow among Mohave ground squirrel populations found low levels of 
subdivision among Mohave ground squirrel populations including between 
Coolgardie Mesa and EAFB (Bell 2006, pp. 43, 72), indicating that gene 
flow among Mohave ground squirrel populations including from the 
Coolgardie Mesa population west to EAFB has occurred over the long 
term. In addition, we did not find any information that indicates the 
population in the southern portion, where impacts are concentrated, 
provides genetic diversity to the species as a whole. Bell (2006, pp. 
18, 39, 40) found low genetic diversity throughout the range of the 
species, indicating that gene flow occurs throughout the range. 
Therefore, we conclude that the Southern and the Central portions of 
the range of the Mohave ground squirrel, individually and in 
combination, do not provide an essential contribution to the 
representation of the species.
    Based on the discussion above, we have determined that the Mohave 
ground squirrel does not face elevated threats in most portions of its 
range, and that those portions of the Mohave ground squirrel's range 
that may have concentrated threats (the Southern and the Central 
portions of the range) do not contribute to the resiliency, redundancy, 
and representation of the Mohave ground squirrel such that without 
these portions, the species would be in danger of extinction. 
Accordingly, we find that the Mohave ground squirrel is not endangered 
or threatened in a significant portion of its range.
    We do not find that the Mohave ground squirrel is in danger of 
extinction now, nor is it likely to become endangered within the 
foreseeable future throughout all or a significant portion of its 
range. Therefore, listing the Mohave ground squirrel as endangered or 
threatened under the Act is not warranted at this time.
    We request that you submit any new information concerning the 
status of, or threats to, the Mohave ground squirrel to our Ventura 
Fish and Wildlife Office (see ADDRESSES section) whenever it becomes 
available. New information will help us monitor this species and 
encourage its conservation. If an emergency develops for this or any 
other species, we will act to provide immediate protection.

References Cited

    A complete list of references cited is available on the Internet at 
http://www.regulations.gov and upon request from the Ventura Fish and 
Wildlife Office (see ADDRESSES section).

Author

    The primary authors of this notice are staff members of the Ventura 
Fish and Wildlife Office (see ADDRESSES section).

    Authority: The authority for this action is section 4 of the 
Endangered Species Act of 1973, as amended (16 U.S.C. 1531 et seq.).

    Dated: September 23, 2011.
Gregory E. Siekaniec,
 Acting Director, U.S. Fish and Wildlife Service.
[FR Doc. 2011-25473 Filed 10-5-11; 8:45 am]
BILLING CODE 4310-55-P