Diversity
Species diversity measured by Shannon Weaner index is directly proportional to the number of species in the sample and the uniformity of the species distribution in the total abundance [45]. In the three lakes species diver-sity was relatively high, which indicates good environ-mental conditions conducive to the development of many species, and according to Kajak [46] - moderate trophy of waters. It was only in wet season samples that values were much lower which was reflected by the lowest re-corded number of species in the zooplankton community [47] as well as by the domination of single species, ac-companied by low proportions of other taxa. This indi-cated poor lake conditions. This hypothesis that decrease in lake condition followed by community structure sim-plification was also confirmed by Rogozin [48].
4.5. Trophic State Index (Tsi)