[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]
BILLING CODE 4310-55-P