Spatio-temporal interrelations of three sympatric species of voles (Mammalia: Rodentia) in the South Urals
Institute of Plant and Animal Ecology, Ural Branch,
Russian Academy of Sciences
ul. 8 Marta, 202, Yekaterinburg 620144, Russia
e-mail: zig@ecology.uran.ru
The structural and functional organization and the spatiotemporal interrelations of three sympatric vole species (Microtus oeconomus, Clethrionomys, rutilus, and C. rufocanus) were analyzed on territories different in the type of their functional significance to the animals (survival stations, zones of temporary dispersal, and transit zones). The study was conducted in the environs of the Iremel massif (54°31'25" N 58°50'18" E) in 1979-1981, in four 1 ha marking-areas in four different altitudinal zones. It is shown that the abundance and demographic structure is different for each species pair in each area, whereas their dynamics is synchronous. The overlap of niches in two Clethrionomys species is small and cannot cause their competition for food. The distribution of voles within the areas is usually independent, but has some peculiarities depending on the type of territory usage by the animals. Preferred microterritories that help species to avoid competition are revealed for each species to occur in different areas. These are cases of spatial separation, not of ecological isolation of sympatric species. Spatial and temporal division of environmental resources is controlled by mechanisms that have developed in the process of the community's evolution.
