Zoobenthos Research in Medium-Size and Small Rivers of the Lower Volga River Basin

This article provides an overview of studies of macrozoobenthos and meiobenthos of medium and small rivers of the Lower Volga basin. The study of macrozoobenthos in this region is mainly aimed at determining the taxonomic diversity, quantitative indicators, and patterns of formation of bottom communities under the influence of natural and anthropogenic factors. Since the end of the 18th century, the tasks of researchers have gradually expanded from inventory–faunal to determining the quantitative, structural and functional characteristics of communities. The study of the macrozoobenthos of rivers is considered in the context of the features of development in various climatic zones of the Lower Volga River basin: forest-steppe, steppe, and semidesert and belonging of rivers to the basins of the Kuibyshev, Saratov, and Volgograd reservoirs. The middle rivers in all natural and climatic zones have been studied most fully, while information about the zoobenthos of most small watercourses is often absent or sketchy. To date, the communities of meiobenthos remain practically unexplored in both medium and small rivers. At the present stage, much attention is paid to the zonal distribution of macrozoobenthos; it is promising to study the functional features of meiobenthos and macrozoobenthos.