Analysis of the Structure of the Metacommunity of Plankton and Bottom Organisms in Rivers of the Lake Elton Basin

A statistical analysis was performed on hydrochemical and hydrobiological data obtained from samples of macrozoobenthos, meiobenthos, and zooplankton in 2013 and 2018 from different biotopes of the five highly mineralized rivers of the basin of the hyperhaline Lake Elton. The general trends in the formation of the species structure of the metacommunity of aquatic organisms are considered based on the Lybold-Mikkelson concepts. Randomized null models are used to test hypotheses on the consistent occurrence of species ( coherence ), the formation of compact species associations ( boundary clumping ), and the regular change in the species composition along environmental gradients ( turnover ). The nature of changes in biotic diversity were determined to be nonstationary and intermittent, and the taxonomic structure was highly mosaic, which is characteristic of stochastic-type ecosystems. A close correlation was established within individual mixed associations of benthic and planktonic species due to biotic interactions and the coordinated response of organisms to environmental factors. Statistical models Random Forest and subsequent multivariate analysis were used to identify groups of species by the degree of tolerance to external abiotic influences, and the sets of factors having a significant impact were established.