Seasonal Dynamics and Resources of Forage Zoobenthos of Sivash as a Key Area for the Waders Migrating Along the Afro-Eurasian Flyways

Abstract

Results of nine years of the research (19942002) dedicated to the role of aquatic invertebrates in the distribution of longdistance migrating species of tundra waders. The stocks of forage resources and their seasonal dynamics were assessed for the first time. Forage resources of Sivash exceeded the tundra waders intake as follows: in Eastern Sivash during the spring migration-21.528.7 times, during the autumn migration-6.210.9 times; in Central Sivash-2.4 times in spring, and 5.7 times in autumn, respectively. A total of 22 species of aquatic invertebrates were recorded in the diet. They included 2 species of Polychaeta, 7 species of Crustacea (Anostraca-1, Isopoda-3, Amphipoda-3 species), 11 species of Gastropoda and insect larvae-2 species. Among the taxonomic groups, the greatest number of species was represented by mollusks and crustaceans. Research shows that Sivash can be referred to the most valuable wetland in Eastern Europe for longdistance migrants due to the consistently high indices of forage macrozoobenthos and extensive shallows suitable for bird feeding during their migratory stopovers.