[Federal Register Volume 75, Number 80 (Tuesday, April 27, 2010)]
[Proposed Rules]
[Pages 22063-22070]
From the Federal Register Online via the Government Publishing Office [www.gpo.gov]
[FR Doc No: 2010-9377]
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DEPARTMENT OF THE INTERIOR
Fish and Wildlife Service
50 CFR Part 17
[FWS-R8-ES-2010-0006]
[MO 92210-0-0008 B2]
Endangered and Threatened Wildlife and Plants; 90-day Finding on
a Petition to List the Mohave Ground Squirrel as Endangered with
Critical Habitat
AGENCY: Fish and Wildlife Service, Interior.
ACTION: Notice of 90-day petition finding and initiation of status
review.
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SUMMARY: We, the U.S. Fish and Wildlife Service (Service), announce a
90-day finding on a petition to list the Mohave ground squirrel
(Xerospermophilus mohavensis) as an endangered species under the
Endangered Species Act of 1973, as amended (Act). Based on our review,
we find that the petition presents substantial scientific or commercial
information indicating that listing the Mohave ground squirrel may be
warranted. Therefore, with the publication of this notice, we are
initiating a status review of the species to determine if listing the
species is warranted. To ensure that this status review is
comprehensive, we are requesting scientific and commercial data and
other information regarding this species. Based on the status review,
we will issue a 12-month finding on the petition, which will address
whether the petitioned action is warranted, as provided in section
4(b)(3)(B) of the Act. We will make a determination on critical habitat
for this species, which was also requested in the petition, if and when
we initiate a listing action.
DATES: To allow us adequate time to conduct this review, we request
that we receive information on or before June 28, 2010. After this
date, you must submit information directly to the Ventura Fish and
Wildlife Office (see FOR FURTHER INFORMATION CONTACT section below).
Please note that we may not be able to address or incorporate
information that we receive after the date noted above.
ADDRESSES: You may submit information by one of the following methods:
Federal eRulemaking Portal: http://www.regulations.gov.
Search for docket FWS-R8-ES-2010-0006 and then follow the instructions
for submitting comments.
U.S. mail or hand-delivery: Public Comments Processing,
Attn: FWS-R8-ES-2010-0006; Division of Policy and Directives
Management; U.S. Fish and Wildlife Service; 4401 N. Fairfax Drive,
Suite 222; Arlington, VA 22203.
We will post all information received on http://www.regulations.gov. This generally means that we will post any
personal information you provide us (see the Information Solicited
section below for more information).
FOR FURTHER INFORMATION CONTACT: Michael McCrary, Listing and Recovery
Coordinator, Ventura Fish and Wildlife Office, 2593 Portola Road, Suite
B, Ventura, CA 93003; telephone (805) 644-1766; facsimile (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:
Information Solicited
When we make a finding that a petition presents substantial
information indicating that listing a species may be warranted, we are
required to promptly review the status of the species (status review).
For the status review to be complete and based on the best available
scientific and commercial information, we request information on the
Mohave ground squirrel from government agencies, Native American
Tribes, the scientific community, industry, and any other interested
parties. We seek information on:
(1) The species' biology, range, and population trends, including:
(a) Habitat requirements for feeding, breeding, and sheltering;
(b) Genetics and taxonomy;
(c) Historical and current range, including distribution patterns;
(d) Historical and current population levels, and current and
projected trends; and
(e) Past and ongoing conservation measures for the species, its
habitat, or both.
[[Page 22064]]
(2) Historical and current survey information on the Mohave ground
squirrel, including survey methods and design, time of year, weather
information, time of day, site selection method, and descriptions of
physical characteristics of landscapes, soil, and vegetation.
(3) The factors that are the basis for making a listing
determination for a species under section 4(a) of the Act (16 U.S.C.
1531 et seq.), which are:
(a) The present or threatened destruction, modification, or
curtailment of the species' 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.
(4) Information on management programs for the conservation of the
Mohave ground squirrel.
(5) Information on current or expected future development within
the range of the Mohave ground squirrel, including but not limited to:
the extent or magnitude of habitat loss, degradation, or fragmentation
from development for energy, transportation, agriculture, military
training; land management prescriptions; or recreation, and how they
may affect the conservation of the Mohave ground squirrel.
(6) Information on the population status of predators of the Mohave
ground squirrel, including information on the occurrence and extent/
severity of predation by coyotes, house cats, common ravens, domestic
dogs, and feral dogs on the Mohave ground squirrel, and the effect of
this predation on the Mohave ground squirrel's long-term survival.
(7) Information on morphological, behavioral, genetic, or
ecological variability in the Mohave ground squirrel, and any change in
that variability.
(8) Information on environmental change within the range of the
Mohave ground squirrel.
(9) Information on the importance of certain areas or populations
to the long-term conservation of the Mohave ground squirrel that may
help us identify potentially significant portions of the species'
range. This may include information that demonstrates the following
factors are important to a portion of the Mohave ground squirrel's
range:
(a) The quality, quantity, and distribution of habitat relative to
the biological requirements of the species;
(b) The historical values of the habitat to the species;
(c) The frequency of use of the habitat; and
(d) The uniqueness or importance of the habitat for other reasons,
such as breeding, feeding, seasonal movements, wintering, or
suitability for population expansion, or for genetic diversity.
Please include sufficient information with your submission (such as
full references) to allow us to verify any scientific or commercial
information you include.
If, after the status review, we determine that listing the Mohave
ground squirrel is warranted, we will propose critical habitat (see
definition in section 3(5)(A) of the Act), in accordance with section 4
of the Act, to the maximum extent prudent and determinable at the time
we propose to list the species. Therefore, within the geographical
range currently occupied by the Mohave ground squirrel, we request data
and information on:
(1) What may constitute ``physical or biological features essential
to the conservation of the species'';
(2) Where these features are currently found; and
(3) Whether any of these features may require special management
considerations or protection, including managing for the potential
effects of climate change.
In addition, we request data and information on ``specific areas
outside the geographical area occupied by the species'' that are
``essential for the conservation of the species.'' Please provide
specific comments and information as to what, if any, critical habitat
you think we should propose for designation if the species is proposed
for listing, and why such habitat meets the definition of critical
habitat in section 3 of the Act and the requirements of section 4 of
the Act.
Submissions merely stating support for or opposition to the action
under consideration without providing supporting information, although
noted, will not be considered in making a determination. Section
4(b)(1)(A) of the Act directs that determinations as to whether any
species is an endangered or threatened species must be made ``solely on
the basis of the best scientific and commercial data available.''
You may submit your information concerning this finding by one of
the methods listed in the ADDRESSES section. If you submit information
via http://www.regulations.gov, your entire submission--including any
personal identifying information--will be posted on the website. If you
submit a hardcopy that includes personal identifying information, you
may request at the top of your document that we withhold this personal
identifying information from public view. However, we cannot guarantee
that we will be able to do so. We will post all hardcopy submissions on
http://www.regulations.gov.
Information and supporting documentation that we received and used
in preparing this finding, will be available for public inspection at
http://www.regulations.gov, or by appointment, during normal business
hours, at the U.S. Fish and Wildlife Service, Ventura Fish and Wildlife
Office (see FOR FURTHER INFORMATION CONTACT).
Background
Section 4(b)(3)(A) of the Act requires that we make a finding on
whether a petition to list, delist, or reclassify a species presents
substantial scientific or commercial information indicating that the
petitioned action may be warranted. We are to base this finding on
information provided in the petition, supporting information submitted
with the petition, and information otherwise available in our files. To
the maximum extent practicable, we are to make this finding within 90
days of our receipt of the petition and publish our notice of this
finding promptly in the Federal Register.
Our standard for substantial scientific or commercial information
within the Code of Federal Regulations (CFR) with regard to a 90-day
petition finding is ``that amount of information that would lead a
reasonable person to believe that the measure proposed in the petition
may be warranted'' (50 CFR 424.14(b)). If we find that substantial
scientific or commercial information was presented, we are required to
promptly commence a review of the status of the species, which is
subsequently summarized in our 12-month finding.
Petition History
On September 5, 2005, we received a petition, dated August 30,
2005, from Defenders of Wildlife and Dr. Glenn R. Stewart to list the
Mohave ground squirrel as endangered, and to designate critical habitat
concurrently with the listing. The petition identified the scientific
name for Mohave ground squirrel as Spermophilus mohavensis; however,
the name was changed in 2009 to Xerospermophilus mohavensis (Helgen et
al. 2009, p. 273), and we refer to it in this petition finding by its
current name. The petition clearly identified itself as such and
included the requisite identification information for the petitioners,
as required in 50
[[Page 22065]]
CFR 424.14(a). The petition contained detailed information on the
natural history and biology of the Mohave ground squirrel, and the
current status and distribution of the species. It also contained
information on what the petitioners reported as potential threats to
the species. In a March 28, 2006, letter to the petitioners, we
informed them that we would not be able to address their petition at
that time because further action on the petition was precluded by court
orders and settlement agreements for other listing actions that
required us to use nearly all of our listing funds for fiscal year
2006. We also stated our initial review of the petition did not
indicate that an emergency situation existed and that emergency listing
was not necessary.
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 to list
the Mohave ground squirrel as a threatened species. At that time, the
species was a category 2 candidate (November 15, 1994; 59 FR 58988),
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).
Species Information
The Mohave ground squirrel (Xerospermophilus mohavensis) is a
distinct, full species with no recognized subspecies. The petitioners
presented sufficient, reliable information related to the taxonomic
status of the Mohave ground squirrel. It was discovered in 1886 by F.
Stephens and described as a distinct monotypic species by Merriam
(1889, p. 15). The type locality is near Rabbit Springs in the Lucerne
Valley, San Bernardino County, California.
The Mohave ground squirrel is a medium-sized squirrel. Total length
is approximately 23 centimeters (cm) (9 inches (in)) with a tail length
of 6.4 cm (2.5 in). The upper body is grayish brown, pinkish gray,
cinnamon gray, and pinkish cinnamon without stripes or flecking. The
underparts of the body and the tail are white (Ingles 1965, p. 171).
The skin is darkly pigmented and dorsal hair tips are multi-banded.
The closest relative of the Mohave ground squirrel is the round-
tailed ground squirrel (Xerospermophilus tereticaudus). It has a
contiguous, but not overlapping, geographic range with the Mohave
ground squirrel.
Mating and Reproduction
The Mohave ground squirrel mating season occurs from mid-February
to mid-March (Harris and Leitner 2004, p. 1). Recht (c.f. Gustafson
1993, p. 83) reported that male Mohave ground squirrels are territorial
during the mating season. Females may enter male Mohave ground squirrel
territory and remain for 1 or 2 days. After copulation, the females
establish their own home ranges. John Harris (personal communication,
Mills College, Oakland, CA, as cited in the petition, p. 14) observed
male Mohave ground squirrels staking out the overwintering sites of
females to mate with them when they emerged.
Gestation is about 30 days with litter size ranging from four to
nine (Best 1995, p. 3). Parental care continues through mid-May, with
juvenile Mohave ground squirrels emerging above ground between 10 days
to 2 weeks later (Gustafson 1993, p. 84). Mortality for juveniles is
high during the first year with more male Mohave ground squirrels lost
than females. Female Mohave ground squirrels can breed at 1 year of age
if environmental conditions are favorable (Leitner and Leitner 1998, p.
28).
The reproductive success of the Mohave ground squirrel is dependent
on the amount of fall and winter precipitation. Leitner and Leitner
(1998, p. 20) found a positive correlation between fall and winter
rainfall and recruitment of juvenile squirrels the following year. In a
low rainfall year, Mohave ground squirrels may forego breeding, or the
low availability of food due to low rainfall may cause reproductive
failure (Leitner and Leitner 1998, p. 29).
Range and Distribution
The presumed historical range of the Mohave ground squirrel, which
is based on the current range and historical locations of suitable
habitat, is the northwest portion of the Mojave Desert in parts of
Inyo, Kern, Los Angeles, and San Bernardino Counties, California. This
area is bounded on the south and west by the San Gabriel, Tehachapi,
and Sierra Nevada ranges, and on the northeast by the Owens Lake and
Coso, Slate, Quail, Granite, and Avawatz Mountains. The southeastern
edge of the historical range is bordered by the Mojave River with the
exception of one locality east of the Mojave River in the Lucerne
Valley. The historical range of the Mohave ground squirrel is assumed
to have included that area of the Antelope Valley west of the
communities of Palmdale, Lancaster, Rosamond, and Mojave, although
there are no records of the species being sighted or captured there.
The current range of the Mohave ground squirrel is similar to the
historical range, except it excludes the western portion of the
Antelope Valley in Los Angeles and Kern Counties and possibly some of
the area from Victorville to the south and southeast to Lucerne Valley
in San Bernardino County. Urban and agricultural development in these
areas has resulted in the loss or modification of Mohave ground
squirrel habitat. The Mohave ground squirrel has the smallest range of
any ground squirrel species in the United States. Gustafson (1993, p.
8) states the geographic range of the Mohave ground squirrel
encompasses approximately 1,968,000 hectares (ha) (4,863,000 acres
(ac)).
Activity Patterns, Movements, and Home Range
The active season for the Mohave ground squirrel is short,
generally from early March to August (Bartholomew and Hudson 1960, p.
194), but may begin as early as mid-January to late February.
Initiation depends on temperature and elevation (Gustafson 1993, p.
19). During this time, Mohave ground squirrels must mate, gather enough
nutrition to produce and sustain a litter, and ensure nutritional
reserves to last during the inactive season. During the inactive
season, Mohave ground squirrels exist in their burrows in a state of
torpor (a state of reduced physiological activity or sluggishness) to
conserve their reserves of energy and water.
The length of the active season varies by sex, age, and
availability of food resources. In dry years, which are often non-
reproductive years, Mohave ground squirrels may enter their state of
torpor as early as spring (Leitner et al. 1995, p. 83). The active
season for an adult is shorter than for a juvenile as adults do not
need to acquire as much energy for the inactive season as juveniles do.
The active season for an adult female is generally longer than for a
male because females need to acquire additional energy for litter
production and lactation (Leitner et al. 1997, pp. 114-115).
[[Page 22066]]
Mohave ground squirrels are diurnal; they spend much of the day
above ground (Recht 1977, p. 56). As temperatures increase into the
spring and early summer, Mohave ground squirrels will spend more time
in the shade of shrubs or briefly use their burrows. Burrows are
usually located beneath large shrubs. Mohave ground squirrels may use
several burrows at night throughout a season; they also use other
burrows for predator avoidance and temperature regulation. The burrow
used for the inactive season is dug specifically for that period (Recht
1977, p. 9).
Mohave ground squirrels exhibit a behavior called natal dispersal.
Upon dispersing from the burrow where they were born, some males will
move and take up residence at least 1,009 meters (m) (3,280 feet (ft))
from the natal burrow while females move a shorter distance of 200 to
300 m (650 to 980 ft) from their natal burrows (Leitner and Leitner
1998, p. 34; Harris and Leitner 2005, p. 191).
The home range of the Mohave ground squirrel varies among years and
between sexes during the mating season. The mean home range is 0.74 ha
(1.83 ac) for mating females and 6.73 ha (16.63 ac) for males. Outside
the breeding season, the mean home range size is 1.20 ha (2.96 ac) for
females and 1.24 ha (3.06 ac) for males (Harris and Leitner 2004, pp.
520-521).
Population Demographics
The behavioral characteristics of the Mohave ground squirrel, as
discussed above, make it difficult to determine or estimate population
status and trends because the species spends much of the year
underground and populations appear to be sensitive to both seasonal and
annual rainfall patterns. That is, in dry years or dry fall seasons,
reproduction during the following spring season may be unsuccessful and
population size may contract (Leitner and Leitner 1998, pp. 29-31).
Survey results suggest that the Mohave ground squirrel has a patchy
distribution throughout its range (Hoyt 1972, p. 7; Gustafson 1993, p.
viii). Most reported information describes the number of animals
trapped or number trapped as compared to the trapping effort. We are
aware of only one location where information on population trend was
available (Leitner 2005, p. 3). In the northwest portion of the range
of the Mohave ground squirrel, trapping results are available for the
Coso Range within China Lake Naval Air Weapons Station (NAWS). The
surveys span 1992 to 1996 and 2001 to 2005. The total number of Mohave
ground squirrels captured during the first survey period was more than
twice that of the second (Leitner 2005, p. 3).
Brooks and Matchett (2002) analyzed the data from all known Mohave
ground squirrel studies. Forty-nine percent of the sites were
identified from observing or trapping only one animal.
Habitat and Life History Requirements
The habitat requirements of the Mohave ground squirrel are varied.
The species has been found in a variety of vegetative communities
including Mojave Creosote Scrub, Desert Saltbush Scrub, Desert Sink
Scrub, Desert Greasewood Scrub, Shadscale Scrub, and Joshua Tree (Yucca
brevifolia) Woodland (Gustafson 1993, pp. ix, 81). Creosote Bush Scrub
is the vegetation community in which the Mohave ground squirrel is most
often found. Mohave ground squirrels usually inhabit flat to moderately
sloping terrain. They prefer deep rather than shallow soils and
gravelly soils rather than sandy soils (Aardahl and Roush 1985, p. 23).
Soil characteristics are important as the Mohave ground squirrel
constructs burrows for temperature regulation, predator avoidance, and
inactive season use.
The food habits of the Mohave ground squirrel are diverse. Recht
(1977, p. 80) called the Mohave ground squirrel a facultative
specialist; its foraging strategy falls between that of a specialist
and a generalist. The Mohave ground squirrel specializes in foraging on
certain plant species over short periods of time. As the availability
of forage species changes throughout the active season, the Mohave
ground squirrel adapts its foraging strategy to maximize energy intake
in a changing environment. Observations and fecal analysis indicate
that Mohave ground squirrels consume a variety of annual and perennial
plants and arthropods (Leitner and Leitner 1992, p. 12; Gustafson 1993,
pp. 77-83). At one study site, the leaves of three shrub species made
up 60 percent of the Mohave ground squirrel diet based on fecal
analysis (Leitner and Leitner 1998, p. 34). In a study by Leitner and
Leitner (1992) in the northern part of its range, the Mohave ground
squirrel was found to consume leaves of annual and perennial plants,
their fruits and seeds, fungi, and butterfly larvae. Mohave ground
squirrels appear to exploit food sources that are available on an
intermittent basis. They may also select particular food items over
others because of higher water content. Leitner and Leitner (1992, p.
25) concluded that the Mohave ground squirrel is flexible in exploiting
high-quality food resources.
Predation and Mortality
There is little documentation on the natural predators of the
Mohave ground squirrel. There is circumstantial evidence of predation
by coyotes (Canis latrans), prairie falcons (Falco mexicanus), and
common ravens (Corvus corax) (Leitner et al. 1997, p. 49; J. Harris,
personal communication, as cited in the petition, p. 15). There may be
other natural predators of the Mohave ground squirrel.
Mortality is high for the Mohave ground squirrel during the first
year and appears to be skewed toward males (Brylski et al. 1994, p. 64;
Leitner and Leitner 1998, p. 28). Mortality may also be caused by
extended periods of low amounts of fall and winter rainfall, which
results in reduced availability of forage and water, and can increase
vulnerability to disease.
Evaluation of Information for This Finding
Section 4 of the Act (16 U.S.C. 1533), and implementing regulations
at 50 CFR 424, set forth the procedures for adding species to, or
removing a species from, the Federal Lists of Endangered and Threatened
Wildlife and Plants. A species may be determined to be an endangered or
threatened species due to one or more of the five factors described in
section 4(a)(1) of the Act: (A) The present or threatened destruction,
modification, or curtailment of its habitat or range; (B)
overutilization for commercial, recreational, scientific, or
educational purposes; (C) disease or predation; (D) the inadequacy of
existing regulatory mechanisms; or (E) other natural or manmade factors
affecting its continued existence.
In making this 90-day finding, we evaluated whether information on
threats to the Mohave ground squirrel, as presented in the petition and
other information available in our files, is substantial, thereby
indicating that the petitioned action may be warranted. Our evaluation
of this information is presented below.
A. The Present or Threatened Destruction, Modification, or Curtailment
of the Species' Habitat or Range
Evaluation of Information Provided in the Petition and Available in
Service Files
The petitioners presented information regarding threats to the
Mohave ground squirrel from reduced range and habitat destruction,
including: urban and rural
[[Page 22067]]
development on private and public lands; agricultural development;
military activities; livestock grazing; transportation; energy
development; and that the cumulative impacts of drought, habitat
destruction, habitat fragmentation, and decrease in precipitation with
climate change pose a threat greater than the drought episodes to which
the Mohave ground squirrel is adapted.
The range of the Mohave ground squirrel is the smallest of all
ground squirrels in the United States. Based on information provided by
the petitioners, the Mohave ground squirrel appears to have been nearly
extirpated from the southern portion of its range, which represents
approximately 20 percent of its range (Leitner as cited in the
petition, p. 8). This assertion is based on the results of surveys
conducted for the Mohave ground squirrel from 2002 to 2004 (Leitner
2004 as cited in the petition, p. 17). The portion of the recently
reduced range includes an area south of State Highway 58 in the
Palmdale-Lancaster area and the Victorville to Lucerne Valley area.
Private Lands
On private lands, which comprise about 31 percent of the current
range of the Mohave ground squirrel, the petitioners claim 2.8 percent
of the range of the Mohave ground squirrel has been lost to urban and
rural development and approximately 2 percent (37,000 ha (92,000 ac))
to agricultural fields. The information on impacts to the Mohave ground
squirrel from agricultural development was derived from Hoyt (1972, p.
8), Aardahl and Roush (1985, p. 2), and Gustafson (1993, pp. 23-24).
The petitioners also stated that they have no updated data to quantify
the extent or intensity of this threat. We have no information in our
files to dispute the figures presented by the petitioners; however, we
currently do not have information to determine whether a 2.8 percent
loss to urban and rural development and a 2 percent loss to
agricultural development is biologically significant to the Mohave
ground squirrel.
Public Lands
Public lands managed by the Bureau of Land Management (BLM) account
for about 31.8 percent of the species' range. The petitioners stated
that BLM's land management plan for the West Mojave Desert (West Mojave
Plan) would allow new development throughout much of the range of the
Mohave ground squirrel and would not protect the four Mohave ground
squirrel ``core areas'' (see petition, p. 17). ``Core areas'' are
defined by the petitioners as locations where Mohave ground squirrels
have been reliably captured over time, or where there are thriving
populations. The petitioners stated that activities that result in the
loss of habitat in these ``core areas'' or prevent dispersal among
these ``core areas'' will impede and eventually prohibit conservation
of the Mohave ground squirrel.
Public land managed by the Department of Defense accounts for about
34.5 percent of the species' current range. The petitioners stated that
current military training at Fort Irwin threatens Mohave ground
squirrels by crushing animals, compacting and otherwise disturbing
soils, collapsing burrows, destroying shrubs used for cover, and
reducing spring annual plants used by Mohave ground squirrels for
forage (Bury et al. 1977, pp. 16, 18). According to the petitioners,
Fort Irwin's training currently affects 7.4 percent of the range of the
Mohave ground squirrel, and the proposed expansion of Fort Irwin will
affect additional lands within the range of the Mohave ground squirrel
and will fragment one of the four Mohave ground squirrel ``core areas''
as identified by the petitioners.
Additionally, 2.7 percent of the current range of the Mohave ground
squirrel occurs on other public `protected lands' (see petition, p. 40)
including; federally designated wilderness areas, State park land,
California Department of Fish and Game land, and the Desert Tortoise
Natural Area.
Livestock Grazing
The petitioners stated that livestock grazing has the potential to
degrade Mohave ground squirrel habitat through changes in soil
structure, including accelerated erosion and collapsing burrows,
changes in vegetative structure, reduced availability of native forage
species (Laabs 2002, p. 5; Campbell 1988, pp. 569, 574), and direct
competition with Mohave ground squirrels for limited quality and
quantity of forage (Leitner and Leitner 1998; pp. 29, A6, A7, A15, and
A23). According to the petitioners' GIS analysis, 27 percent of the
range of the Mohave ground squirrel has been impacted by livestock
grazing.
Aardahl and Roush (1985, p. 23), as cited in the petition, stated
that ``land uses which affect the availability of forbs and grasses
have the potential to influence the long-term population of the Mohave
ground squirrel,'' but this does not ``mean that properly managed
livestock grazing will cause a significant negative impact on the
Mohave ground squirrel.'' Twenty-one of 22 study sites surveyed were
grazed by sheep or cattle in varying degrees; the study site with the
highest total adjusted captures of Mohave ground squirrels showed
considerable signs of grazing (Aardahl and Roush 1985, p. 23). The
petitioners did not provide information, and we have no information in
our files, on the extent or magnitude of the impacts of livestock
grazing on the Mohave ground squirrel.
Transportation
The petitioners identified the extensive network of highways and
roads in the range of the Mohave ground squirrel as a threat. The
petitioners claim impacts from highway and road establishment and
vehicle use include habitat loss, fragmentation, and degradation, and
direct mortality from vehicle strikes (Gustafson 1993, pp. 23, 26; BLM
2003, p. 30; Leitner as cited in the petition, p. 22). The petitioners
stated that there is evidence of surface disturbance to roadsides up to
400 m (1,312 ft) away from the road, and that 37 percent of transects
conducted by the BLM in the West Mojave Desert were bisected by roads.
The petitioners calculated that the total area of the network of roads
and highways affected 65,964 ha (163,000 ac) or 3.3 percent of the
range of the Mohave ground squirrel. The petitioners provided
additional information that impacts from roads on the desert tortoise
have been documented more than 3,962 m (13,000 ft) from the highest
level traffic road (Hoff and Marlow 2002, p. 454) and that similar
impacts likely occur to the Mohave ground squirrel.
We do not agree that impacts to the desert tortoise from roads that
have been measured more than 3,962 m (13,000 ft) from the highest
traffic roads are the same as those to the Mohave ground squirrel. The
Hoff and Marlow study (2002, p. 454) reported on the abundance of
desert tortoise sign at intervals from roads. This study was specific
to the desert tortoise. It did not examine the effects of roads on the
Mohave ground squirrel. Therefore, any application of the results from
this research to the Mohave ground squirrel is inferred and is not
supported by the data. However, we agree with the petitioners that
roads and highways result in direct mortality to Mohave grounds
squirrels from vehicle collisions and habitat loss and degradation.
Energy Development
According to the petitioners, geothermal exploration and
development and the construction of
[[Page 22068]]
solar energy plants in the range of the Mohave ground squirrel have
caused, and will likely cause, adverse impacts to the Mohave ground
squirrel and loss or degradation of habitat (Leitner and Leitner 1989,
p. 2). The petitioners did not quantify the amount of habitat affected.
We acknowledge that energy development for geothermal and solar energy
has occurred within the range of the Mohave ground squirrel and that
this development can result in the degradation or loss of habitat used
by the Mohave ground squirrel. The petitioners do not provide
information, and we do not have information in our files, on the extent
of this loss or degradation and how it will affect the conservation of
the Mohave ground squirrel.
Cumulative Impacts of Habitat Destruction, Fragmentation, and Decreased
Precipitation
The petitioners provided information that indicates the
reproduction and survival of the Mohave ground squirrel is ultimately
linked to rainfall (Harris and Leitner 2004, pp. 517, 518). Mohave
ground squirrels may fail to persist in certain areas during drought
episodes (Leitner and Leitner 1998, p. 31). The petitioners assert the
cumulative impacts of habitat destruction, habitat fragmentation, and
overall decrease in precipitation due to climate change are a greater
threat to the Mohave ground squirrel than the periods of low rainfall
and drought episodes with which the Mohave ground squirrel evolved.
Based on information from the Intergovernmental Panel on Climate
Change (Watson et al. 2002, pp. 8, 9), we acknowledge temperatures in
southern California are likely to increase and precipitation is likely
to decrease in the future. With hotter, drier conditions and more
extreme weather patterns in southern California than those with which
the Mohave ground squirrel evolved, the species may be negatively
affected. However, we believe that climate change models that are
currently available are not yet capable of making meaningful
predictions of climate change for specific, local areas such as the
range of the Mohave ground squirrel (Parmesan and Matthews 2005, p.
354). We are not currently aware of models that predict how climate in
the range of the Mohave ground squirrel will change, and we do not know
how any change may alter the range of, or otherwise threaten, the
species.
Summary of Factor A
In summary, the petitioners presented information regarding threats
to the Mohave ground squirrel from reduced range and habitat
destruction, including: urban and rural development on private and
public lands; agricultural development; military activities; livestock
grazing; transportation; and energy development. We found the petition
and information in our files presents substantial information that
these activities may have contributed to a recent range contraction in
the southern portion of the Mohave ground squirrel's range, and may
threaten the Mohave ground squirrel across its current range by
removing shrubs needed for cover and forage, disturbing soil, or
removing or degrading other habitat features necessary for Mohave
ground squirrel life history requirements. Additionally, one or more of
these activities may threaten what the petitioners identify as ``core
areas'' for the Mohave ground squirrel by removing habitat, fragmenting
the habitat, and preventing dispersal among the ``core areas.''
However, we determined the petition does not present substantial
information indicating that climate change may be a threat to the
species. Additionally, information on the subject of climate change in
our files is not specific to the Mohave ground squirrel. We will
evaluate the effects of climate change, including reduced precipitation
and any cumulative effects of habitat fragmentation or loss on the
Mohave ground squirrel, when we conduct our status review.
On the basis of our evaluation of the information in the petition
and information in our files, we determined that the petition presents
substantial information indicating that listing the Mohave ground
squirrel as endangered may be warranted due to destruction,
modification, or curtailment of the species' habitat or range.
B. Overutilization for Commercial, Recreational, Scientific, or
Educational Purposes
The petitioners did not provide information or list any threats to
the Mohave ground squirrel from overutilization for commercial,
recreational, or educational purposes. The petitioners stated that the
utilization of the Mohave ground squirrel for scientific purposes is
strictly controlled by the California Department of Fish and Game.
Summary of Factor B
On the basis of our evaluation, we determined that the petition
does not present substantial information indicating that listing the
Mohave ground squirrel as endangered may be warranted due to the
overutilization for commercial, recreational, scientific, or
educational purposes. Additionally, we do not have substantial
information in our files to suggest that overutilization for
commercial, recreational, scientific, or educational purposes may
threaten the Mohave ground squirrel. However, we will evaluate all
factors, including threats from overutilization for commercial,
recreational, scientific, or educational purposes, when we conduct our
status review.
C. Disease or Predation
Evaluation of Information Provided in the Petition and Available in
Service Files
The petitioners did not provide information or list any threat to
the Mohave ground squirrel from disease, and we do not have information
in our files regarding potential threats to this species due to
disease.
The petitioners stated that there is little documentation of the
Mohave ground squirrel's natural predators, but claimed that predation
by coyotes, common ravens, house cats, domestic dogs, and feral dogs is
a concern. Although the petitioners stated that cats prey on small
mammals and dogs dig up rodent burrows, they did not present any
information on the level of mortality or population impacts from
predation for Mohave ground squirrels, any other ground squirrel
species, or any small mammal species. The petitioners noted that the
numbers of common ravens and coyotes, known predators of the Mohave
ground squirrel, have increased, posing an increased predation risk to
Mohave ground squirrel populations. However, there is no information
provided that the numbers of cats, dogs, common ravens, or coyotes have
increased in the range of the Mohave ground squirrel, and there is no
evidence to indicate that there is increased predation by these
predators on the Mohave ground squirrel. We do not have information in
our files to indicate that predation is a threat to the survival of the
Mohave ground squirrel.
Summary of Factor C
On the basis of our evaluation, we determined that the petition
does not present substantial information indicating that listing the
Mohave ground squirrel as endangered may be warranted due to disease or
predation. Additionally, we do not have substantial information in our
files to suggest that disease or predation threaten the Mohave ground
squirrel. However, we will evaluate all factors, including threats from
disease and
[[Page 22069]]
predation, when we conduct our status review.
D. The Inadequacy of Existing Regulatory Mechanisms
Evaluation of Information Provided in the Petition and Available in
Service Files
The petitioners stated that current regulations have proven
inadequate to conserve the Mohave ground squirrel; that only 9 percent
of the range of the Mohave ground squirrel has any kind of protected
status; and that, although the Mohave ground squirrel is a State-listed
species, this listing provides no conservation assurances for the
Mohave ground squirrel on Federal lands.
The California Endangered Species Act provides protection for the
Mohave ground squirrel on private and State-owned land, and on Federal
lands in relation to activities carried out by non-Federal entities
that are required to obtain a State permit or authorization.
The major military installations within the range of the Mohave
ground squirrel have implemented Integrated Natural Resources
Management Plans that cover the Mohave ground squirrel and implement
actions to manage for the species. In their management plan for the
West Mojave Desert, the BLM considers the Mohave ground squirrel an
umbrella species, a species whose habitat requirements include those of
many other species and whose conservation should automatically conserve
a host of other species. BLM has implemented a plan that establishes a
Mohave ground squirrel Conservation Area that contains 35 percent of
the species' historical range on BLM land.
Summary of Factor D
On the basis of our evaluation, we determined that the petition
does not present substantial information indicating that listing the
Mohave ground squirrel as endangered may be warranted due to the
inadequacy of existing regulatory mechanisms. Additionally, we do not
have substantial information in our files to suggest that existing
regulatory mechanisms are inadequate and thus threaten the Mohave
ground squirrel. However, we will evaluate all factors, including
threats from the inadequacy of existing regulatory mechanisms, when we
conduct our status review.
E. Other Natural or Manmade Factors Affecting the Species' Continued
Existence
Evaluation of Information Provided in the Petition and Available in
Service Files
The petitioners stated that pesticide use may adversely affect the
Mohave ground squirrel. According to the petitioners, Mohave ground
squirrels live in native vegetative communities adjacent to
agricultural fields and other areas where rodenticides are used. Mohave
ground squirrels use these areas for forage and shelter. The
petitioners claim that if rodenticides are used on agricultural fields,
Mohave ground squirrels could be adversely affected, or they could be
exterminated by the State Rodent Program. In the early part of the 20th
century, the Los Angeles Agricultural Commission used poison grain to
target and eliminate ground squirrels in the Antelope Valley, which
includes the historical range of the Mohave ground squirrel.
Although we are aware that rodenticides, such as those that include
strychnine as the active ingredient, may be used to kill ground
squirrels, there is no information in the petition or our files to
indicate that rodenticides are used to specifically target Mohave
ground squirrels or that any rodenticides currently used within the
range of the Mohave ground squirrel are adversely affecting the status
of this species.
Summary of Factor E
On the basis of our evaluation, we determined that the petition
does not present substantial information indicating that listing the
Mohave ground squirrel as endangered may be warranted due to other
natural or manmade factors affecting its continued existence.
Additionally, we do not have substantial information in our files to
suggest that other natural or manmade factors threaten the Mohave
ground squirrel. However, we will evaluate all factors, including
threats from other natural or manmade factors affecting its continued
existence, when we conduct our status review.
Finding
The petition and supporting information have identified numerous
factors affecting the Mohave ground squirrel, including: reduced range,
urban and rural development, agricultural development, military
activities, livestock grazing, transportation and energy development,
and cumulative impacts of habitat destruction, fragmentation, and
decreased precipitation (Factor A); predation (Factor C); the lack of
regulatory mechanisms protecting the species and its habitat (Factor
D); and pesticide use (Factor E).
On the basis of our evaluation under section 4(b)(3)(A) of the Act,
we have determined that the petition presents substantial scientific or
commercial information indicating that listing the Mohave ground
squirrel as endangered may be warranted. This finding is based on
information provided by the petitioners and in our files for Factor A.
In particular, there is substantial information to indicate habitat
based threats under Factor A may remove shrubs needed for cover and
forage, disturb soil, or remove or degrade other habitat features
necessary for Mohave ground squirrel life history requirements across
its current range. The information provided by the petitioners and in
our files for Factors B, C, D, and E was not substantial. In
considering what factors might constitute threats, we must look beyond
the mere exposure of the species to the factor to determine whether the
species responds to the factor in a way that causes actual impacts to
the species. If there is exposure to a factor, but no response, or only
a positive response, that factor is not a threat. If there is exposure
and the species responds negatively, the factor may be a threat and we
then attempt to determine how significant a threat it is. If the threat
is significant, it may drive or contribute to the risk of extinction of
the species such that the species may warrant listing as threatened or
endangered as those terms are defined by the Act. This does not
necessarily require empirical proof of a threat. The combination of
exposure and some corroborating evidence of how the species is likely
impacted could suffice. The mere identification of factors that could
impact a species negatively may not be sufficient to compel a finding
that listing may be warranted. The information shall contain evidence
sufficient to suggest that these factors may be operative threats that
act on the species to the point that the species may meet the
definition of threatened or endangered under the Act.
Because we have found that the petition presents substantial
information that listing the Mohave ground squirrel may be warranted,
we are initiating a status review to determine whether listing the
Mohave ground squirrel under the Act is warranted. We will issue a 12-
month finding as to whether the petitioned action is warranted.
The ``substantial information'' standard for a 90-day finding
differs
[[Page 22070]]
from the Act's ``best scientific and commercial data'' standard that
applies to a status review to determine whether a petitioned action is
warranted. A 90-day finding does not constitute a status review under
the Act. In a 12-month finding, we will determine whether a petitioned
action is warranted after we have completed a thorough status review of
the species, which is conducted following a substantial 90-day finding.
Because the Act's standards for 90-day and 12-month findings are
different, as described above, a substantial 90-day finding does not
mean that the 12-month finding will result in a warranted finding.
The petitioners also requested that we designate critical habitat
for the Mohave ground squirrel. If we determine in our 12-month finding
that listing the Mohave ground squirrel is warranted, we will address
the designation of critical habitat at the time of the proposed
rulemaking.
References Cited
A complete list of all references cited is available on the
Internet at http://www.regulations.gov and upon request from the
Ventura Fish and Wildlife Office (see FOR FURTHER INFORMATION CONTACT
section above).
Author
The primary authors of this notice are staff members of the Ventura
Fish and Wildlife Office (see FOR FURTHER INFORMATION CONTACT section
above).
Authority
The authority for this action is the Endangered Species Act of
1973, as amended (16 U.S.C. 1531 et seq.).
Dated: April 12, 2010
Signed: Daniel M. Ashe
Deputy Director, U.S. Fish and Wildlife Service
[FR Doc. 2010-9377 Filed 4-26-10; 8:45 am]
BILLING CODE 4310-55-S