Zoobenthos of littoral zone of natural monument - karst lake Bolshoe Paraskino (Komi Republic)

In the basin of the river Tobys, 50 km south of Ukhta, there are 20 different in size and shape karst lakes interconnected by underground rivers. This place known as "Paraskiny ozera" has the category of Regional Natural Monument and was included in the Nature Protected Areas system of the Komi Republic in 1989. This category means special protection regime of the territory that can be used for recreation only. On weekends, the lakes are visited by groups of tourists who carry out cutting of trees, fishing, making bonfires, move on vehicles off the roads, arrange garbage dumps in the coastal areas of the lakes, etc. Among the lakes of the area, the largest lake (4.8 hectares) is Bolshoe Paraskino. The state of this lake strongly depends on the watershed area. The anthropogenic impact increases the load on aquatic ecosystems, pollution of the environment, creates threats to the preservation of lakes and lake biota. During the autumn-summer period of 2005, we performed hydrobiological studies in the littoral zone of lake Bolshoe Paraskino in order to reveal main qualitative, quantitative and structural parameters of zoobenthos - the main and reliable source of information about the ecological state of the lake. 15 different systematical groups of invertebrates were found in the studied littoral zoobenthos: Nematoda, Oligochaeta, Hirudinea, Mollusca, Cladocera, Ostracoda, Сopepoda, Аmphipoda, Hydracarina, Ephemeroptera, Megaloptera, Trichoptera, Odonata, Ceratopogonidae, Chironomidae. In summer, chironomid larvae and oligochaetes prevailed in the zoobenthos; in autumn - chironomid larvae and mollusks. The main biomass of zoobenthos was represented by mollusks; among them some rare European species were found. Glacial relic crustacean Rivulogammarus lacustris Sars. was found in the lake.