Population Fluctuations of Voles in North Fennoscandian Tundra: Contrasting Dynamics in Adjacent Areas with Different Habitat Composition

摘要: During 1991-1996. we studied population fluctuations of microtine rodents (primarily Clethrionomys rufocanus). their winter food plants, and predators in a low arctic habitat complex, dominated by unproductive lichen dwarf-birch tundra. More productive habitats occurred patchwise throughout the landscape. On south-facing slope, scrubland prevailed, luxuriant were locally abundant. Our main method was live-trapping on 14 grids, representing typical lowland tundra (5 replicates), slope (4 replicates) barren high-altitude replicates). Within vole populations cyclic. In primarily seasonal, but erash coincided with phase relatively densities lowland. The highland characterised densities. rapid growth, long-range dispersal within from to surrounding areas. Moreover, small mustelids which had initially been present only started move elsewhere, along natural corridors. Shoot mortalities plant. Vaccinium myrtillus. remained low. observed scenario is consistent hypothesis that cycles represent mustelid-microtine limit cycle, because created this mechanism should disappear when habitats, capable supporting resident predators, become fragmented embedded vast unsuitable area.