Freshwater Mollusks of the Vyatka-Kama Interfluve

Abstract

Data on the structure of malacocenoses in unregulated flow of the upper Vyatka and Kama basin are summarized. Freshwater malacofauna is formed by 58 species from 9 families represented mainly by widespread species with European and European–Western Siberian types of distribution range. Mollusks are typical for all benthic ecosystems in the Vyatka River. The maximum species diversity is recorded in the upper reaches of the river and is mainly represented by Gastropoda (53%). Bivalvia (58–71%) are dominant downstream. The structure of Unionidae varies along the longitudinal profile of the river: Unio crassus and Pseudanodontakletii are common in overgrown upper reaches; Unio tumidus and Unio pictorum are common along the river bed. The species composition of Sphaeriidae is relatively stable; Sphaerium radiatum, S. rivicola, and Pisidum amnicum are dominant. Bivalvia are dominant in terms of the abundance and biomass in most benthic ecosystems of the Vyatka and Kama rivers.