ЗООПЛАНКТОН МАЛЫХ ОЗЕР ВОСТОЧНОЙ ЧАСТИ ВОДОСБОРА ОЗЕРА ВОЖЕ (ВОЛОГОДСКАЯ ОБЛАСТЬ)

Abstract

In the summer period of 2017–2020, the authors studied the composition, dominant complex and the abun-dance of zooplankton in 23 small lakes in the eastern part of the Lake Vozhe catchment area (Vologda oblast). The lakes are located in lacustrine-glacial, moraine-hilly and moraine-plain landscapes. A total of 121 species are recorded in zooplankton of the lakes (Rotifera – 38, Cladocera – 56, Copepoda – 27) including Holopedium gibberum, Daphnia pulex, Bunops serricaudata, Paralona pigra, Chydorus ovalis, Acanthodiaptomus denticornus denticorn that are relatively rare species for the region. The highest occurrence is typical for eurybiontic species. The planktonic fauna of the waterbodies of lacustrine-glacial terrains is sui generis (the index of similarity with other lakes is 0.4). The level of similarity in the composition of zooplankton in moraine lakes is 0.7 on average. Zooplankton in the lakes of different landscape types differs in the structure of dominant complex. The set of dominants in the reservoirs of the lacustrine-glacial terrains is sui generis (Keratella cochlearis, Daphnia galeata, Eudiaptomus graciloides, Heterocope appendiculata). The composition of zooplankton dominants in moraine lakes is more diverse. Most of these waterbodies are dominated by Kellicottia longispina, Keratella cochlearis, Bosmina longirostris, Thermocyclops oithonoides. In the lakes of the moraine-hilly landscape, the set of dominants also includes Eudiaptomus gracilis and E. graciloides, and in the moraine-plain water bodies Asplanchna priodonta, Diaphanosoma brachyurum, Ceriodaphnia pulchella, Polyphemus pediculus are dominant. The highest average abundance (137.7 thousand ind./m3) and biomass (1.8 g/m3) are typical for the lakes in moraine-plain landscapes. The morphology of the depressions of these lakes contributes to the development of macrophyte thickets. The abundance and biomass of zooplankters in waterbodies of the lacustrine-glacial landscapes are 58.9 thousand ind./m3 and 0.8 g/m3, respectively. The development of macrophytes in these reservoirs is limited by a rapid increase in depth and the predominance of peat and peat-silt soils.