Long-Term Dynamics of the Avifauna in the North of Western Siberia

Abstract

Changes in the avifauna of the three large regions of the north of the Yamalo-Nenets Autonomous Okrug (Russia), the Lower Ob River region, the floodplain of the Lower Ob, and the Yamal Peninsula, have been analyzed for a period of more than 60 years. The analysis is based on relative estimates of the number of species on a 4-point scale; cases of significant shifts in the species ranges also have been considered. It is shown that avifaunae in the long term are highly dynamic formations, the process of their changes is of a permanent nature. Its scale is about half of the species composition for 60 years and its directions vary greatly in different regions, depending on the degree of anthropogenic transformation of the territory. Areas with a relatively low anthropogenic impact (the Lower Ob and the Ob floodplain) are characterized by the predominance of the positive trends, mainly expressed in the appearance of new species. Many of them (more than 25% of the modern species composition) have been detected in the Ob floodplain, which indicates the canalization of the penetration process for new species to the north. The Yamal Peninsula region, where the anthropogenic impact associated with domestic reindeer overgrazing is high, is characterized by the predominance of the negative trends in the form of a decrease in the number of typical tundra species.