[Federal Register Volume 60, Number 173 (Thursday, September 7, 1995)]
[Proposed Rules]
[Pages 46569-46571]
From the Federal Register Online via the Government Publishing Office [www.gpo.gov]
[FR Doc No: 95-22171]
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DEPARTMENT OF THE INTERIOR
50 CFR Part 17
Endangered and Threatened Wildlife and Plants; 90-Day Finding for
a Petition to List the Mohave Ground Squirrel as Threatened
AGENCY: Fish and Wildlife Service, Interior.
ACTION: Notice of 90-day petition finding.
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[[Page 46570]]
SUMMARY: The U.S. Fish and Wildlife Service (Service) announces the 90-
day finding on a petition to list the Mohave ground squirrel
(Spermophilus mohavensis) under the Endangered Species Act (Act) of
1973, as amended. The Service finds that the petition did not present
substantial information indicating that the petitioned action may be
warranted.
DATES: The finding announced in this document was made on August 4,
1995. Comments and materials related to this petition finding may be
submitted to the Field Supervisor at the address listed below.
ADDRESSES: Information, data, comments, or questions concerning the
status of the petitioned species should be submitted to the Field
Supervisor, Fish and Wildlife Service, Ventura Field Office, 2493
Portola Road, Suite B, Ventura, California 93003. The complete file for
this finding is available for public inspection, by appointment, during
normal business hours at the above address.
FOR FURTHER INFORMATION CONTACT: Kate Symonds at the Ventura Field
Office (see ADDRESSES section) or at 805/644-1766.
SUPPLEMENTARY INFORMATION:
Background
Section 4(b)(3)(A) of the Endangered Species Act of 1973, as
amended (16 U.S.C. 1533 et seq.) (Act), requires that the Service make
a finding on whether a petition to list, delist, or reclassify a
species presents substantial scientific or commercial information to
indicate that the petitioned action may be warranted. This finding is
to be based on all information available to the Service at the time the
finding is made. To the maximum extent practicable, this finding is to
be made within 90 days of the date the petition was received, and the
finding is to be published promptly in the Federal Register. If the
finding is that substantial information was presented, the Service also
is required to commence a review of the status of the species.
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 (Spermophilus mohavensis) as a threatened
species. The species is a category 2 candidate (November 15, 1994; 59
FR 58988), which was first included in this category on September 18,
1985. Category 2 includes taxa for which sufficient information on
biological vulnerability and threats is not currently available
indicating that listing as endangered or threatened is warranted.
The Mohave ground squirrel ranges throughout the northwest portion
of the Mojave Desert of California. The species spends about 7 months a
year, usually from August to February, estivating in burrows. Timing of
estivation is presumably related to sufficient accumulation of fat
reserves (Bartholomew and Hudson 1960, Ingles 1965, Tomich 1982).
Entrance into estivation may begin from June to September. In years
with abundant food supplies, adults may enter estivation in late June
and juveniles may enter in late July. Adults are more likely than
juveniles to enter estivation early because adults do not need to gain
as much weight as juveniles to survive the long estivation underground
(Gustafson 1993). Males tend to enter estivation earlier than females
because they do not need to put energy into milk production and feeding
of young before they store fat (Leitner and Leitner 1992). Mating
occurs soon after emergence from estivation and a litter of 4-6 young
are born after a gestation period of 28-30 days. Mohave ground
squirrels are generally less active when air temperatures drop below 88
deg.F or exceed 98.1 deg.F (Bartholomew and Hudson 1960). The diet
consists of seeds, flowers, forbs, shrubs, grasses, fungi, and
arthropods, although the species has demonstrated flexibility in
utilizing food items as annual availabilities change (Recht 1977,
Leitner and Leitner 1992).
Mohave ground squirrels have been found in all vegetation
associations and up to 5,600 feet in elevation within its 7,600 square
mile range (Hoyt 1972, Gustafson 1993). Gustafson (1993) reported that
Mohave ground squirrels have been found in Holland's (1986) communities
of Mohave wash scrub, desert sink scrub, and desert greasewood scrub.
Nonetheless, the species appears to prefer large alluvial-filled
valleys and deep, fine-to-medium textured soils vegetated with creosote
bush scrub, shadscale scrub, or alkali sink scrub wherever desert
pavement is absent (Aardahl and Roush 1985). The Mohave ground squirrel
rarely is found in mountainous or rocky terrain, or dry lake beds,
although exceptions have been recorded (Zembal and Gall 1980, Wessman
1977).
Excluding mountainous or rocky areas, and dry lake beds, the Mohave
ground squirrel habitat is distributed over an estimated 7,200 square
miles (Gustafson 1993). This figure excludes those plant communities
and soil types in which the species has never been found. Without
precise habitat information, it is difficult to assess the severity of
habitat loss. In addition, insufficient data are available on specific
habitat requirements to precisely delineate the acreage of Mohave
ground squirrel habitat. Specific information on habitat requirements
would also facilitate the rating of areas based on habitat quality.
In making a finding as to whether a petition presents substantial
commercial and scientific information to indicate the petitioned action
may be warranted, the Service must consider whether the petition is
accompanied by a detailed narrative justification [50 CFR
Sec. 424.14(b)(2)(ii)]. The regulations require the Service to
``consider whether such petition * * * [p]rovides information regarding
the status of the species over all or a significant portion of its
range'' [50 CFR Sec. 424.14(b)(2)(iii)], including current
distributional and threat information. Furthermore, the Service is
required to ``consider whether such petition * * * [i]s accompanied by
appropriate supporting documentation in the form of bibliographic
references, reprints of pertinent publications, copies of reports or
letters from authorities, and maps'' [50 CFR Sec. 424.14(b)(2)(iv)].
In assessing the substantiality of this petition, the Service
reviewed several published and unpublished studies, agency documents,
literature syntheses, commercial data, and field sighting records. The
Service also interviewed researchers and other persons familiar with
the species' biology. In addition, the petitioner was contacted to
provide additional supporting information, which he was unable to
provide. On the basis of the best scientific and commercial information
available, the Service finds that the petition did not provide reliable
data, recent or otherwise, throughout the species' range regarding
specific habitat requirements, and population abundance and trends.
Moreover, the petition did not include any data linking some activities
(e.g., rural development, off-road vehicle use, Fort Irwin training)
with long-term absence of the ground squirrel or on the extent to which
these activities may be degrading habitat. Also, the petitioner failed
to provide convincing data that grazing by domestic sheep and cattle
adversely affects the habitat of the Mohave ground squirrel. Finally,
the petition did not include any information to assess the extent and
configuration of habitat loss due to fragmentation to determine whether
this threatens the species. Therefore, given the uncertainties
associated with urban growth and other threats in the Mojave
[[Page 46571]]
Desert, and the lack of credible studies on the biological status of
the species, the Service finds that the petition did not present
substantial information indicating that the listing of the Mohave
ground squirrel may be warranted. Given these data uncertainties, the
Mohave ground squirrel will remain a species of concern to the Service.
References Cited
A complete list of references used in the preparation of this
finding is available, upon request, from the Ventura Field Office (see
ADDRESSES section).
Author
The primary author of this document is Kate Symonds, Ventura Field
Office (see ADDRESSES section).
Authority
The authority for this action is the Endangered Species Act of
1973, as amended (16 U.S.C. 1531 et seq.).
Dated: August 4, 1995.
John G. Rogers,
Acting Director, Fish and Wildlife Service.
[FR Doc. 95-22171 Filed 9-6-95; 8:45 am]
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