Население мелких млекопитающих подтайги Южного Зауралья

Abstract

On the basis of materials obtained using two generally accepted counting methods, data on the species composition of small mammals, the ratio of background and dominant species, the total abundance in the main groups of biotopes of the South Trans-Ural region are presented. The differences in the community structure of small mammals in the subtaiga and forest-steppe sub-zone of the South Trans-Ural region have been analysed. The paper discusses materials on the community of small mammals in the sub-taiga of the South Trans-Ural region. A brief history of the study of this group of animals is reviewed. The use of two counting methods (the ditch with pitfalls and trap-lines) allowed the most complete identification of the species composition of insectivores and rodents in the sub-taiga of the South Trans-Ural region in 2021. In terms of species, the ditch with pitfalls were more effective, with 17 species identified; trap-lines counted 13 species. The abundance of animals in 2021 was very low. In our opinion, was determined by the abnormally hot spring and summer period. On average, only rare and very rare species have been recorded in the snap-trap counts in the study area. Numerous species were absent in the average meaning regardless of the method of capture. The core of small mammals of the sub-taiga of the South Trans-Ural region consisted of species typical of humid habitats and small-leaved forests, such as the Laxmann's shrew Sorex caecutiens, common shrew S. araneus and Eurasian pygmy shrew S. minutus rodents, as well as the common vole Microtus arvalis and harvest mouse Micromys minutus (surveys using the ditch with pitfalls). The common shrew was predominant in the snap-trap counts, accounting for about 45% of the total abundance of all animals recorded. In pine forests with poor productivity and in open spaces, the total abundance of insectivores and rodents is lowest. The species composition of small mammals of the sub-taiga and forest-steppe subzone of the South Trans-Ural region are largely similar (83% of the total species). Specific features of the taiga subzone were determined by the taiga shrew Sorex isodon and Siberian chipmunk Eutamias sibiricus, unusual for the forest-steppe and herb-bunchgrass steppe subzone of the South Trans-Ural region. A characteristic feature of the sub-taiga of the South Trans-Ural region is a specific proportion of the northern red-backed vole Myodes rutilus and European bank vole M. glareolus, their abundance is comparable, or the M. glareolus predominates, which is not observed in the forest-steppe. In the sub-taiga, in the surveys using ditch with pitfalls among insectivores and rodents, the Laxmann's shrew prevailed, its share was approximately one fourth of all recorded animals, although in general the community of small mammals is polydominant, in contrast to the surveys using the trap-line method, where one species dominated – the common shrew. In 2021 (sub-taiga) as well as in 2020 (forest-steppe) the territory of the South TransUral region was characterized by a deep depression of water vole Arvicola amphibius numbers, which was completely absent in the counts.