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

The 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 was 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 XVIII century, the tasks of research 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 peculiarities development in various climatic zones of the Lower Volga River basin: forest-steppe, steppe and semi-desert 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, a promising direction is to study the functional features of meiobenthos and macrozoobenthos.