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Perognathus alticolus

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Taxonomy [top]

Kingdom Phylum Class Order Family
ANIMALIA CHORDATA MAMMALIA RODENTIA HETEROMYIDAE

Scientific Name: Perognathus alticolus
Species Authority: Rhoads, 1894
Common Name(s):
English White-eared Pocket Mouse
Synonym(s):
Perognathus alticola Rhoads, 1894 [orth. error]
Taxonomic Notes: This mouse formerly was known as Perognathus alticola, but the original and correct spelling of the specific name is alticolus (Jones et al. 1992, Best 1994, Patton in Wilson and Reede, 2005). Recent electrophoretic investigations confirm the specific separation of P. a. inexpectatus from P. parvus (though Patton in Wilson and Reede, 1993, 2005, stated that alticolus may be only subspecifically distinct from P. parvus). Best (1994), Baker et al. (2003), and Patton (in Wilson and Reeder 2005) listed alticolus as a distinct species.

Assessment Information [top]

Red List Category & Criteria: Endangered B1ab(iii) ver 3.1
Year Published: 2008
Date Assessed: 2008-06-30
Assessor(s): Linzey, A.V. & NatureServe (Hammerson, G.)
Reviewer(s): Amori, G. (Small Nonvolant Mammal Red List Authority) & Chanson, J. (Global Mammal Assessment Team)
Justification:
Listed as Endangered because its extent of occurrence is less than 20,000 km², it is rare, no localities are within protected areas, and the extent and quality of its habitat is continuing to decline because of timbering and cattle grazing. Of the two recognized subspecies, one (P. a. alticola) has not been collected since 1934 and is possibly extinct.
History:
1994 Vulnerable (Groombridge 1994)
1990 Vulnerable (IUCN 1990)
1988 Vulnerable (IUCN Conservation Monitoring Centre 1988)

Geographic Range [top]

Range Description: The white-eared pocket mouse is known from two disjunct mountain ranges in southern California in the United States: the San Bernardino Mountains in San Bernardino County (subspecies alticolus), and the Tehachapi Mountains, in Kern, Ventura, and Los Angeles counties (subspecies inexpectatus), at elevations of about 3,500-6,000 feet (1,070-1,830 m asl). The two subspecies are separated by the San Gabriel Mountains.
Countries:
Native:
United States (California)
Range Map: Click here to open the map viewer and explore range.

Population [top]

Population: Despite focused surveys, no specimens of subspecies alticolus have been obtained since the 1930s; this subspecies appears to be rare or extinct. Subspecies inexpectatus is also uncommon (D. F. Williams, cited by Best, 1994). Searches from 1979-1981, involving 81,938 trap nights, yielded only three specimens from a single locality (D. F. Williams). Trapping by Sulentich (1983) produced 11 specimens from two localities on the eastern side of Tehachapi Pass, in an area where a single specimen was caught in 1975 (Williams, 1978). Since 1978, occurrence at three localities has been verified; several historical sites for inexpectatus were not searched and probably still are occupied (D. F. Williams). The current population trend is unknown, but the species already appears to have declined to a small extent of occurrence, area of occupancy, number of subpopulations, and population size.
Population Trend: Decreasing

Habitat and Ecology [top]

Habitat and Ecology: Available information indicates that habitat is primarily open grassy/weedy/dry bracken areas among sagebrush and other shrubs in ponderosa/Jeffrey pine, pinyon/juniper, or montane hardwood-conifer associations. Secondary habitat is also open areas in Joshua tree and high desert shrub associations and old-field communities of herbaceous plants in high desert scrub associations, arid annual grassland (e.g., rangeland dominated by introduced grasses), and a fallow grain field dominated by Russian thistle (Sulentich, 1983; Williams, 1986; Best, 1994).

At higher elevations, this rodent is found in yellow pine forest with bracken fern and pinyon-juniper woodland habitats. At lower elevations, chaparral and coastal sage scrub habitat is occupied. It is a nocturnal species, remaining in burrows during the day and emerging at night to forage on a variety of plant and animal matter. Seeds are carried in cheek pouches to underground storage chambers.
Systems: Terrestrial

Threats [top]

Major Threat(s): Current threats to the species are related to its increased vulnerability to habitat modification due to its restricted and patchy distribution (Nowak, 1999). Habitat is used for timber production, but the effect of this is unknown. The species may be threatened by cattle grazing, but the effects of different levels of grazing are not known. Many of the mountain valleys within the potential range of subspecies alticolus are privately owned and have been developed or inundated by reservoirs; with exception of a Forest Service fire lookout tower, the area surrounding Strawberry Peak is privately owned and largely developed (Winter, 1998).

Conservation Actions [top]

Conservation Actions: This species is not listed as threatened or endangered; some historical localities are on public land but habitat is unprotected. Further surveys are needed in potential habitat throughout its historical range and in contiguous potential habitat. Areas likely to support populations are the mountain slopes of the Tehachapi and San Gabriel ranges that front on the Mojave Desert (Williams, 1986). All known occurrences should be protected, but no data are available to determine the type of protection needed, other than protection from development. Information is needed on basic biology, ecology, and the taxonomic relationship between the two subspecies.

Citation: Linzey, A.V. & NatureServe (Hammerson, G.) 2008. Perognathus alticolus. The IUCN Red List of Threatened Species. Version 2014.2. <www.iucnredlist.org>. Downloaded on 02 September 2014.
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