Areographic Structure of Charadriiformes in the Lake Baikal Basin
An analysis of the structure of local faunas without an arealogical component will be incomplete, since it does not always reflect well the degree of their connection with the fauna of other regions. The purpose of this work is to identify the species composition and conduct an arealogical analysis of the fauna of shorebirds in the Baikal basin. The typological analysis is based on the principles of classification of insect ranges adapted to birds. The geographical distribution of 61 bird species was analyzed, excluding migrant species. They were differentiated according to four arealogical complexes: cosmopolitan, Eurasian-North American, Afro-Eurasian and Eurasian, within which we identified 27 arealogical groups, including 6 longitude groups and 15 latitudinal latitudinal groups. Out of 61 species, 7 species (11.4%) nesting ranges cover more than three continents (cosmopolites), 14 species (23.0%) have Eurasian-North American ranges, 3 species (4.9%) are Afro-Eurasian (two of them Palearctic), the remaining 37 species (60.7%) nest on the Eurasian continent, of which 14 species live only in Asia. The share of the latter in the fauna of the Charadriiformes of the Baikal basin is more than one quarter (23.0%). In total, the number of species from the Eurasian and Eurasian-North American complexes (83.6% of the fauna of Charadriiformes) clearly prevails over the cosmopolitan and Afro-Eurasian ones. The analysis demonstrates a very complex arealogical structure of the fauna of Charadriiformes in the basin Baikal and, obviously, in the Asian part of the Palearctic as a whole. Most species of shorebirds are inherent in their original range, and there are practically no two species with the same area of distribution. This picture is connected, first of all, with different requirements for habitat conditions in combination with the history of development and formation of their habitats. Charadriiformes, regularly recorded in the Baikal basin, demonstrate a noticeable diversity in the nature of distribution. The fauna is based on Eurasian, and to a lesser extent, Eurasian-North American species. The proportion of cosmopolitan and Afro-Eurasian species is small. According to the latitudinal component, the charter-like species of the region were distributed over natural zones from the Arctic to subtropical zones, and many species adhere to certain climatic zones. Among the nesting species, the presence of temperant and subboreal species is noticeable, which is due to the ecotone position of the region and the diversity of its landscape and ecological conditions.