Zoo- and Ichthyoplankton in the Communities of Aquatic Plants and in the Adjacent Sections of the Littoral Zone of Various Water Bodies in the Lower Reaches of the Desna River

Abstract

Zoo- and ichthyoplankton in the littoral zone of various water bodies of the lower reaches of the Desna River occurring in the communities of aquatic plants essentially differed from those registered in the adjacent sections free of vegetation. The complicated structure of the environment formed by aquatic plants was responsible for higher taxonomic richness, numbers, and biomass of zooplankton communities compared to the shallow water zone free of vegetation. It should be noted that this phenomenon was observed in early summer as well during the period of ichthyoplankton mass development, which is indicative of the sufficient food base. The highest quantitative indices of zooplankton development were registered in multispecies communities of aquatic plants in floodplain water bodies especially under lentic conditions unlike those occurring in mono-species communities of macrophytes observed in the main riverbed of the Desna River, the development of which was limited by high current velocity. Ichthyoplankton was also registered mainly in macrophyte communities. Its highest species richness, quantitative indices, and the number of size-age groups were observed in the communities of aquatic plants in the semi-flow floodplain water body hydraulically connected to the main riverbed.