Spatial distribution of lemming mats in the Canadian High Arctic

Abstract

Spatial distributions of lemming mats on exposed beach ridges on Bathurst and Devon islands, N. W.T., in the Canadian High Arctic were recorded by triangulation. The collared lemming Dicrostonyx groenlandicus is the only microtine in this region, which eliminates interspecific influences. In addition, vegetation is sparse, making centres of activity easy to identify. Mats were relatively permanent structures with a mean diameter of 3.88 m and an average of 13.0 burrows. The mean nearest neighbour distance ranged from 40 to 45 m and the average mat polygon area (interpreted as territory or home range) was 0.34 ha. Individual mat polygons were contiguous with an average of 5.3 other polygons and the distribution of the mats over the environment was nonrandom. The data support the conclusion that lemming mats represent core areas within lemming territories or home ranges which are distributed regularly over the environment because of social processes which influence social interaction. The data are discussed as they apply to current theories on microtine demography and population dynamics.