Structure of Aquatic Communities in Mountain Lakes of the Torgovaya River Basin (Subpolar Ural)

This paper is analyzes the faunistic composition and quantitative characteristics of aquatic communities in the mountain lakes of the Torgovaya River basin (Subpolar Urals) with special focus on the distribution of Siberian fish and invertebrate species. Aquatic communities of seven mountain lakes have been studied; three of them can be considered as glacial refugia inhabited by the resident form of Arctic grayling. Four species of amphibiotic insects have been identified in the chyme of two grayling species; their main range is in Siberia. The zoobenthos included 16 large taxa; among them, nematodes, entomostracans, and chironomids were dominant in abundance and dipteran and stonefly larvae were dominant in biomass. Twenty eight taxa typical for the fauna of the European northeast of Russia have been identified in the zooplankton. The recorded patterns of distribution of the local aquatic fauna are determined mainly by the glacial history of the Urals. It is assumed that rheophilic benthic invertebrates of Siberian origin colonized the Torgovaya riverbed in the postglacial period.