Taxonomy [top]

Kingdom Phylum Class Order Family
Animalia Chordata Mammalia Rodentia Cricetidae

Scientific Name: Microtus richardsoni
Species Authority: (DeKay, 1842)
Common Name(s):
English Water Vole

Assessment Information [top]

Red List Category & Criteria: Least Concern 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)
Listed as Least Concern because of its wide range, although it is uncommon, its population is stable, and there are no major threats.
Previously published Red List assessments:
1996 Lower Risk/least concern (LR/lc)

Geographic Range [top]

Range Description: This species range is in two distinct segments. The smaller portion extends from the Coast Mountains of western British Columbia in Canada to the Blue and Cascade mountains of Washington and Oregon in the United States. The larger portion extends from the Rocky Mountains of southeastern British Columbia and southwestern Alberta, Canada, southward to western Montana, western Wyoming, Idaho, and central Utah in the United States.
Countries occurrence:
Canada (Alberta, British Columbia); United States (Idaho, Montana, Oregon, Utah, Washington, Wyoming)
Range Map: Click here to open the map viewer and explore range.

Population [top]

Population: This species is considered secure within its range (NatureServe). Populations may fluctuate dramatically yearly or seasonally. In Alberta, monthly density estimates (June-September) in several streamside sites ranged from 0.2 to 12.2 per hectare; seasonal recruitment increased population size 0.8- 6.2 times, with highest numbers in August or September (Ludwig 1988).
Current Population Trend: Stable
Additional data:
Population severely fragmented: No

Habitat and Ecology [top]

Habitat and Ecology: It is a habitat specialist, with a patchy distribution within its range. It prefers subalpine and alpine meadows close to water, especially swift, clear, spring-fed or glacial streams with gravel bottoms, and marshes, or pond edges. It uses underground nests throughout the year. It burrows into stream banks and makes runways in wet meadows. Forested blocks and mountain slopes constitute barriers to movement between suitable habitats.

In Alberta, mating activity was recorded late May or early June through to August or September; young first entered trappable population in early July; maximum of two litters per year; average litter size about 5-6 (range 2-9); about 26% of young bred before their first winter (Ludwig 1988).

Diet includes leaves and occasionally stems of forbs are the major foods. Also eats grasses, sedges and willows. May eat some seeds and insects. Feeds on subterranean parts of plants throughout the year.
Systems: Terrestrial; Freshwater

Threats [top]

Major Threat(s): There are no major threats to this species.

Conservation Actions [top]

Conservation Actions: This species is not of conservation concern.

Citation: Linzey, A.V. & NatureServe (Hammerson, G.). 2008. Microtus richardsoni. The IUCN Red List of Threatened Species 2008: e.T42634A10737385. . Downloaded on 05 October 2015.
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