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Sorex pacificus

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Taxonomy [top]

Kingdom Phylum Class Order Family
ANIMALIA CHORDATA MAMMALIA EULIPOTYPHLA SORICIDAE

Scientific Name: Sorex pacificus
Species Authority: Coues, 1877
Common Name(s):
English Pacific Shrew
Taxonomic Notes: Sorex pacificus formerly was recognized as a subspecies of S. vagrans (Carraway 1985). Nominal species Sorex yaquinae, which has been regarded as a subspecies of S. vagrans or S. pacificus, was regarded by Carraway (1990) as synonymous with S. pacificus pacificus. New subspecies Sorex pacificus cascadensis from the Cascade Range of Oregon was described by Carraway (1990); S. p. pacificus is now limited to the Coast Range in Oregon.

Assessment Information [top]

Red List Category & Criteria: Least Concern ver 3.1
Year Published: 2008
Date Assessed: 2008-06-30
Assessor(s): NatureServe (Hammerson, G.)
Reviewer(s): Amori, G. (Small Nonvolant Mammal Red List Authority) & Chanson, J. (Global Mammal Assessment Team)
Justification:
Listed as Least Concern because it is relatively widespread, there are no major threats, and its population is not declining.

Geographic Range [top]

Range Description: This species' range is limited to western Oregon, including two disjunct areas, one in the Coast Range and the other in the Cascade Range in the United States (Carraway 1990, Verts and Carraway 1998).
Countries:
Native:
United States (Oregon)
Range Map: Click here to open the map viewer and explore range.

Population [top]

Population: This species is represented by at least several dozen occurrences or subpopulations (see map in Verts and Carraway 1998). The total adult population size is unknown, but it does not appear to be uncommon and presumably the population exceeds 10,000, based on the area occupied and typical Sorex densities. This shrew is readily obtained in field surveys; Verts and Carraway (1998) listed 589 museum specimens. Morrison and Anthony (1989) found that only 2% of 829 individuals of 10 species captured were S. pacificus, but the sampling was conducted in early successional clearcuts, which may not be the most favourable habitat for this species, and the methods used may not have been optimal for shrew capture.

The short-term population trend is not definitely known, but probably the extent of occurrence, area of occupancy, number of subpopulations, and population size have not declined more than 10 percent over the past 10 years. The extent of occurrence, area of occupancy, number of subpopulations, and population size probably have not declined more than 25 percent over the long term.
Population Trend: Stable

Habitat and Ecology [top]

Habitat and Ecology: Habitats include moist wooded areas, including especially shady riparian thickets and areas with decaying logs (Bailey 1936; Maser et al. 1981; Morrison and Anthony 1989; Maldonado, in Wilson and Ruff 1999). These shrews tend to avoid grass habitats occupied by S. vagrans (Morrison and Anthony 1989). Typical litter size is four or five, but may vary from two to six (Maser et al. 1981). Reproductively active males are found primarily from February to August; pregnant females recorded 18 April to 1 November (Carraway 1988, Carraway 1985). Apparently some females may produce more than one litter/year (Carraway 1988). It is an active hunter, and feeds primarily on insects but also consumes a large number of other small invertebrates, worms, molluscs, and centipedes. It may eat small amphibians and some vegetable matter. It is active throughout the year. Although some authors have indicated that this species is nocturnal, Verts and Carraway (1998) suspect that activity is "merely depressed in the daytime."
Systems: Terrestrial

Threats [top]

Major Threat(s): No major threats have been identified for this species. It is restricted to part of western Oregon, but is known from at least 50 collection sites; there is little information on population status but evidently it is not threatened.

Conservation Actions [top]

Conservation Actions: This species occurs in at least several protected areas, including Crater Lake National Park and various state parks and natural areas.

Citation: NatureServe (Hammerson, G.) 2008. Sorex pacificus. The IUCN Red List of Threatened Species. Version 2014.2. <www.iucnredlist.org>. Downloaded on 21 October 2014.
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