Vegetation richness and nutrient loads in 16 lakes of Drawienski National Park (Northern Poland)

The paper provides morphometric, physicochemical and vegetation structure of the 16 lakes in Drawienski National Park (DNP). These lakes showed considerable differentiation according to their morphometrical and physico-chemical variables. There are distinguished 4 groups of lakes: (1) throughflow lakes; (2) small, eutrophic non-throughflow lakes; (3) dystrophic lakes with humic water bodies; and (4) mesotrophic lakes. A dependence of the structure of the predominant vegetation types on morphometrical and physico-chemical variables was tested. Results of study of vegetation structure proves the initial classification of the lakes into several groups on the basis of environmental variables. The most important type of vegetation of throughflow lakes are helophytes and nymphaeids. The phytolitoral of eutrophic non-throughflow lakes is scanty. The vegetation of dystrophic lakes is dominated by species with floating leaves and mosses. The common vegetation of mesotrophic lakes is dominated by Chara species and elodeids.