Molluscs of selected water bodies in Warsaw

Abstract

Malacofauna of lakes: Powsinkowskie, Wilanowskie and Czerniakowskie is composed of a similar number of taxa (14–16), but the species composition differs considerably. Mollusc densities are low, frequencies of individual species mostly do not exceed 25%, dominance structure, not very well marked in the deposits, is very clear among the few molluscs living on emerged macrophytes and macrophytes with floating leaves. Species diversity (Shannon-Weaver index) is higher in the bottom deposits, compared to macrophytes. Taxonomic composition of empty shells found in the bottom deposits, indicates that a few dozen year ago the malacofauna of the lakes was richer and similar between the lakes. It apears that the present composition of the malacofauna is affected, among others, by the character of the bottom deposits, transformations of littoral vegetation, level of pollution and trophy of the lakes; the influence of all these factors varies between species