Modern climate changes and dynamics of density and structure of bird population of South Baikal of forest ecosystems in winter period

Abstract

On the basis long-term researches (2010-2021), the features of the formation of the winter population of birds on the right bank of the source of the Angara river (South Baikal) during a period of sharp climate warming are considered. It is shown that the warming was accompanied by a gradual decrease in the total density of the bird population and a noticeable increase in their species diversity. On the key site, were 73 wintering species recorded, of which 28 were new to the region. However, 24 species were previously in this area as nesting, migratory and summering birds found. Only 4 species were really new. All new wintering species differed in insignificant numbers and the increase in the number of wintering species was due to an increase in the comfort of the living conditions of birds as result of climate warming. The relationship between population density birds and the number of wintering species was clearly in certain categories manifested, and only in minor species did it play a certain role in increasing their population density. The reformation of the structure of the bird population in the winter period due to the noticeable warming of the climate was almost completely by the dynamics of the population of the most massive and numerous species of sedentary and migrating for wintering species determined. The decrease in the abundance of birds is clearly associated with a shift in the optima of their ranges to more northern regions.