Paleolimnological assessment of past aquatic vegetation dynamics and ecosytem state in Turkish shallow lakes

Levi, Eti Ester
Since submerged macrophytes are a key primary producer of shallow lakes and are sensitive to environmental changes, macrofossils of them can be used in investigations of past environmental conditions, to infer human introduced environmental impacts (e.g. eutrophication) and to determine past macrophyte communities. The present study includes twenty six shallow lakes, which were chosen along a latitudinal gradient ranging from the North (41°52́N, 27°58́E) to the South (37°06́N, 29°36́E) in Turkey. Sampling for environmental variables and sediment was carried out using a snap-shot sampling protocol (developed within the framework of the EU FP6 project ‘Eurolimpacs’) during the summers of three consecutive years (2006-2008). Surface sediment, short core and long core samples were retrieved from the lakes. The aims of this study were i. to compare the surface sediment plant macrofossils with present day macrophyte taxa of the lakes, ii. to determine the environmental variables potentially influencing the temporal changes in macrophyte communities, and iii. to assess vegetation community dynamics in dated short and long cores. Comparison of plant macrofossil assemblages in surface sediment with present day macrophyte coverage revealed that approximately 41% of the modern taxa were represented among the surface sediment macrofossils. Redundancy analysis (RDA) was carried out for surface macrofossil data with corresponding environmental data. RDA revealed relation of plant species and environmental variables (e.g. Salinity and Najas marina L.). Changes in plant species assemblages in short and long cores from eight lakes chosen along a latitudinal gradient ranging from North to South Turkey is discussed in relation to the RDA results.