Dynamics of the ecological structure of fauna birds in lake Baikal hollow (late XYII – early XXI centuries)

Abstract

The work was performed in the hollow of Lake Baikal (1965-2023). For comparative analysis, the generalizing materials of T.N. Gagina (the end of the XYII – the first half of the XX centuries) were used. By this author, the hollow of Lake Baikal was not identified as an independent ornithogeographic unit and was part of several ornithogeographic sites. At the same time, the hollow differs from the surrounding territories in terms of a complex of physical and geographical conditions and represents a united region. It should be considered as an independent zoogeographic unit – the Baikal complex. Modern climate warming has had a strong impact on the bird fauna of the region. Their fauna increased by 106 species in the second half of the XX – early XXI centuries and now amounts to 427 species of birds (previously 321 species). It should be borne in mind that a slight warming has been observed since the middle of the XVIII century. By the middle of the 20th century, 57 vagrant species had already been recorded here, which clearly expanded the area. However, most of the new species appeared towards the end of the last century and were associated with a series of large, extensive and frequently recurring droughts, followed by long periods of low water, in Central Asia. The process of eviction of birds continues, but at a very slow pace. Few species, ichthyophages and insectivorous, have reached high numbers in the new areas. The remaining species are found in limited numbers as vagrant birds. As a result, the species diversity of birds in the hollow of Lake Baikal has sharply increased, but the number of their main part has remained low.