Structural-functional organization of the littoral zooplankton communities of the Kremenchutskiy reservoir

The present state of the structural and functional organization of the littoral zooplankton communities of the upper Kremenchug Reservoir in the area of the Kaniv Nature Reserve (Ukraine) has been studied. The material was collected during the summer of 2016 at 6 stations of the littoral zone of the upper Kremenchug Reservoir. The research objects were representatives of three main groups of zooplankton (rotifers, cladocerans, copepods), as well as ostracods and larvae of bivalve molluscs. The obtained results represent the present state and organisation of the littoral zooplankton. Species richness of the littoral zooplankton from the upper Kremenchug Reservoir was presented by 48 species. There are 20 species of monogonont rotifers, 18 cladocerans species and 10 copepods. The representatives of the rotifer-cladoceran complex dominated in the taxonomic composition that can be explained by preservation of the river regime and rheophilic conditions in that part of the reservoir. The analysis showed that according to the ecological spectrum of zooplankton groups, the representatives of the pelagic group dominated (47.92 %). As for the feeding type, the largest share was represented by the non-predatory group (64.58 %). After analyzing quantitative indices (density and biomass) of zooplankton, it was found out that they were lower than average for overgrown biotopes (112,580±129,914 ind./m3 and 1.83 ± 2.07 g/m3) and low for open water (26,160 ± 19,161 ind./m3 and 0.82 ± 0.86 g/m3). The conducted studies allow to predict further changes in zooplankton communities, assess the ecosystem and calculate the natural feed supply for fish juveniles.