Palaeolimnological investigations in Poland based on Cladocera (Crustacea)
Abstract The results of subfossil Cladocera analysis obtained from deposits of 26 lakes throughout Poland have been presented. For years throughout Poland a broad range of palaeolimnological studies have been conducted. Their aim is to discover the historical development of water basins and climatic changes in the course of the last 13,000 years and also to investigate the gradual influence of man on the ecosystem with particular emphasis on the last few decades. The hitherto obtained results of palaeolimnological studies, including the results of Cladocera analysis, have yielded information about the development of lakes and provided the basis for plans of certain reservoirs and their basins. Over the past years, analysis of subfossil Cladocera has become one of the leading palaeolimnological methods. The results of detailed qualitative and quantitative analysis of Cladocera remains from sediments of 15 lakes allowed for a reconstruction of the lakes' development. The littoral and limnetic regions, changing trophy, from oligotrophy to advanced eutrophication, changes in pH and fluctuation of water levels, as well as changes resulting from settlement — from Mesolithic and Neolithic through Medieval times until the present — have been reconstructed. For individual lakes, phases of Cladocera development and periods of eutrophication were indicated which partially correlated with certain pollen zones as well as periods of human impact and geochemical effects.