The main regularities of distribution chironomids in benthic communities the central area of the Votkinsk reservoir in long-term perspective

The data of monitoring observations of changes in the structure of chironomid communities of the central region of the Votkinsk reservoir are summarized. Stationary studies were conducted on the basis of the Kama Biological Station from 1975 to 2014. Zoobenthos was harvested during the growing season in the right-bank and left-bank shallow waters, as well as in the deep-water zone of the water. The taxonomic composition has been established, dominant complexes have been identified, quantitative indicators of the development of chironomid larvae on different biotopes of the reservoir have been considered. High qualitative and quantitative indicators of the development of chironomidocenoses are noted on the flooded floodplain of the left-bank shallow water, favorable conditions for the development of chironomid larvae develop here. The study of the seasonal dynamics of the abundance and biomass of chironomid larvae showed that the majority of the chironomid populations living in the right-bank shoal are monocyclic, and both monocyclic and dicyclic species are common on the left bank. Monitoring observations made it possible to establish long-term periods during which the productivity and species composition of chironomidocenoses changed, which is connected with the entry of organic pollutants into the reservoir.