37.

Ogilvie Mountains Collared Lemming

Dicrostonyx nunatakensis

French: Lemming du Yukon / German: Ogilvie-Mountains-Halsbandlemming / Spanish: Lemming de collar de Ogilvie

Other common names: Ogilvie Collared Lemming

Taxonomy. Dicrostonyx torquatus nunatakensis Youngman, 1967, “ Yukon Territory, [Canada]: 20 mi. [= 32 km] S Chapman Lake (lat. 64°35, long. 138°13%), 5500 ft [= 1676 m].”

Dicrostonyx nunatakensis is considered a subspecies of D. groenlandicus by some authorities, but a morphological study noted distinct differences in pelage color that led to recognition of D. nanatakensis as a distinct species. Dicrostonyx nunatakensis is thought to be an isolated Pleistocene relict that has been long separated on glacial nunataks in these mountains from other populations of Dicrostonyx . Additional systematic work on the D. groenlandicus complex is needed to fully understand species limits. Only 16 specimens are known from Trapper Mountain and Seela Range in the greater Ogilvie Mountains Range, but this region has received limited sampling. Monotypic.

Distribution. Ogilvie Mts, N Yukon, Canada.

Descriptive notes. Head—body 117-118 mm, tail length 11-12 mm. No specific data are available for body weight. Ogilvie Mountains Collared Lemmings have dark graybrown pelage above, with thin mid-dorsal stripe, yellowish red ear patches, and pinkish gray belly. They are described as paler than other nearby populations of Dicrostonyx .

Habitat. Rocky alpine habitat in only a few high-elevation sites in the Ogilvie Mountains. On Trappers Mountain and in the Seela Range, Ogilvie Mountains Collared Lemming is associated with dry heath (e.g. Arctous alpinus, Empetrum nigrum, Cassiope tetragona, and Vaccinium vitis-idaea, all Ericaceae, and Betula glandulosa, Betulaceae) habitat (1631-1709 m in elevation) with mountain avens ( Dryas spp., Rosaceae), dwarf willow ( Salix spp.), lichens ( Thamnolia vermicularis, Icmadophilaceae and Flavocetraria nivalis, Parmeliaceae), and grasses (e.g. Anthoxanthum monticola, Poaceae) also present.

Food and Feeding. The Ogilvie Mountains Collared Lemming probably eats plant leaves, flowers, buds, and roots.

Breeding. The Ogilvie Mountains Collared Lemmings probably breeds year-round, with gestation of c.20 days and litters of c.4 young.

Activity patterns. The Ogilvie Mountains Collared Lemming is likely active, feeding day or night.

Movements, Home range and Social organization. Only a few collected specimens of Ogilvie Mountains Collared Lemmings have been old adults, suggesting low overwinter survivorship in a harsh environment with only a three-month growing season.

Status and Conservation. Classified as Least Concern on The IUCNRed List. Ogilvie Mountains Collared Lemming is relatively widespread and faces few anthropogenic impacts.

Bibliography. Jung et al. (2014), Krohne (1982), Musser & Carleton (2005), Rausch (1977), Rausch & Rausch (1972), Slough & Jung (2007), Wilson & Ruff (1999), Youngman (1964, 1967, 1975).