Distribution and abundance of Vancouver Island marmots (Marmota vancouverensis)

Abstract

We analysed historic records and annual counts to assess the population status of Vancouver Island marmots (Marmota vancouverensis). Since 1972, marmots have been found at 47 sites on 15 mountains. All but 2 colonies were located within 5 adjacent watersheds on south-central Vancouver Island. Counts underestimated actual marmot abundance. For most site–year combinations, observers probably counted 66–78% of adults and 75–89% of juveniles. Reproductive colonies typically contained fewer than 5 adults ([Formula: see text], SE = 0.61, n = 34). Most animals were found at elevations above 1000 m (81%), on south- to west-facing slopes (74%). After 1981, marmots colonized 11 habitats created by logging of forests above 700 m. Numbers of adults were above average (134–147%) during the early 1980s and have been near or below average since 1990 (58–99%). The current (1995) population contains 100–200 animals, including 50–100 animals in logged habitats. Marmota vancouverensis is rare primarily because of the small size and patchy distribution of natural subalpine meadows on Vancouver Island. The species is apparently adapted to a metapopulation life-style, in which a network of small colonies exhibit population fluctuations, local extinctions and recolonizations over time.