BIOGEOGRAPHICAL CHARACTERISTICS OF SMALL MAMMALS OF THE HERB-BUNCHGRASS STEPPE AND ADJACENT TERRITORIES IN THE SOUTH TRANS-URAL REGION (KURGAN OBLAST)

Abstract

A brief history of the study of small mammals of the South Trans-Ural region is discussed. On the basis of data obtained using two generally accepted zoological methods (ditch with pitfalls and trap-lines), materials on the small mammal communities are summarized. The species composition, groups of background and dominant species, total abundance of insectivores and rodents were shown to be largely determined by the specific method of animal surveys. In the herb-bunchgrass steppe 18 species of animals were found in the ditch with pitfalls and 11 species in the snap traps surveys. The core of small mammals in this subzone was the common vole, herb wood mouse, tundra and common shrews. In the herb-bunchgrass steppe, as well as in the forest-steppe subzone and subtaiga in spring-summer period, insectivorous and mouse-like rodents were most densely concentrated in near-water biotopes, where there is their high overlap and intra- and interspecific contact, which is especially important for the spread and persistence of various infections. In the subtaiga of the South Trans-Ural region, the optimum complex of conditions is formed for forest-meadow forms, i.e. the Laxmann's and taiga shrews, Siberian chipmunk and bank vole. At the same time, open-space species such as the tundra shrew, southern birch mouse and steppe lemming inhabit the herb-bunchgrass steppe most densely. Of the 22 small mammal species recorded in the South Trans-Ural region in 2020-2022, only one of them, the common shrew, was among the dominant species in all subzones. The taiga shrew and the Siberian chipmunk, which are peculiar only to the subtaiga and do not penetrate into the more southern subzones of the studied territory, made up a special originality among the recorded species of insectivores and rodents of the Southern Trans-Urals.