DYNAMICS OF ZOOPLANKTON OF THE LEBYAZHYE LAKE IN CONNECTION WITH THE ACTIVITIES ON ECOREHABILITATION

The paper presents the results of longstanding (from 1991 to 2016) studies of the zooplankton community of the lake Lebyazhye (Kazan, Russia). In recent decades, under the influence of anthropogenic and natural factors, the water level has decreased and the area of the lake Lebyazhye has reduced. The area of the lake has decreased by 13 times, compared with the 1990's. The water level in the lake is artificially maintained by the supply of groundwater. This caused an increase in the mineralization of water, the predominance of sulfate ions in the ionic composition. This also led to changes in the structure of the zooplankton community. The species composition of zooplankton decreased by more than 20%. New species appeared in the lake, which did not exist before. The number of dominant species has decreased, and the complex of dominant species of zooplankton has changed. The number and biomass of zooplankton have decreased. Earlier, the values of quantitative indicators corresponded to the mesotrophiceutrophic water bodies, but now the reservoir is characterized as oligotrophic. The community is relatively aligned, although it is represented by a small number of species. This is confirmed by the rather high values of the Shannon index, characterizing the species diversity of zooplankton. The results of studies of the zooplankton community of the lake Lebyazhye can be used to justify the measures for the lake's eco-rehabilitation. Keywords: Zooplankton, Eco-Rehabilitation, Lake, Bioindication.