Spatial distribution of diversity in benthic communities of lotic systems in the Middle and Lower Volga region

The spatial variability of species diversity and taxonomic structure of local benthic communities is analyzed based on the results of long-term hydrobiological surveys of benthic communities on 102 small and medium sized rivers in the Middle and Lower Volga basins. Null hypotheses about the absence of statistical dependence of the structural indicators on geographical coordinates in macrozoobenthos communities are tested. It is shown that the overall biodiversity is composed of four characteristic components: species richness, their rarity, uniformity and taxonomic complexity of communities. The most informative indices are selected and their comparative analysis is carried out using the DER algorithm. The spatial distribution of the calculated biotic parameters is illustrated on thematic ecological maps, which are the most important tools for analyzing processes in the meta-community at the species and cenotic levels.