Regularities of Spatiotemporal Dynamics of Chironomid Communities (Chironomidae, Diptera) in the Kuibyshev Reservoir

Abstract

The dynamics of benthic communities of various reaches of the Kuibyshev Reservoir over a long-term observation period 1966 to 2016 has been statistically analyzed. The results of a comparison of the spatial-temporal distribution of structural indicators of chironomid (Chironomidae) communities, including the species diversity and abundance of 48 taxa based on hydrobiological survey data in nine large parts of the reservoir for different years, are presented. Nonparametric analysis of variance revealed a high statistical significance of the variability of the species composition of benthic communities under the influence of temporal and spatial factors. Using multidimensional ordination and generalized Procrustes analysis, the dynamics of the distribution of ecosystem objects (individual species and areas) in the coordinates of two latent axes of maximum variation is shown. A geometric analysis of the multidimensional trajectories of changes in the community of aquatic organisms in individual reaches for different periods of time is carried out. Similar developmental processes of chironomid communities were revealed in a longitudinal succession of reaches on the former channel and sunken floodplain, while the analogous structural characteristics of the Kamskiy reach and eutrophic Cheremshanskiy Bay are specific. The priority role of chironomids as the most important indicator group necessary for biotic assessment of long-term (50 years) changes in the ecological state of a large reservoir is considered.