ABUNDANCE AND DIVERSITY OF ZOOPLANKTON IN THE LITTORAL ZONE OF LAKE LICHEÑSKIE

The aim of the present study was to determine the species diversity and abundance of zooplankton as well as to describe the relationships between the thermal conditions in littoral waters and the numbers and biomass of taxocenoses. The study was conducted in a monthly cycle during the years 2001 and 2002. Thirty-five species belonging to Rotifera and 32 species representing Crustacea were identified. The mean species richness varied significantly in particular months; it was the lowest in June and the highest in September. No significant correlation was found among water temperature and species abundance and the values of the diversity index in the zooplankton community. Zooplankton diversity did not show great fluctuations and was comparable over the entire experimental period. The numbers of Rotifera, Cladocera, and Copepoda were at a similar level, whereas their biomass was highly differentiated. An increase in water temperature was followed by an increase in the abundance and biomass of Cladocera as well as by a decrease in the numbers of Rotifera. The domination of pelagic species was observed in the spring only, while littoral species later assumed the leading position.