MEHNER (T.), DIEKMANN (M.), GARCIA (X.F.), BRÄMICK (U.), LEMCKE (R.), 2005.- Möglichkeiten und Grenzen der Bewertung der ökologischen Qualität von Seen anhand der Fischfauna. Limnologie aktuell, 11: 137-150.


To assess whether fish communities may be used to evaluate the ecological integrity of lakes, a project was conducted that combined data compilation from natural lakes between 50 and 53,470 ha surface area. Whereas littoral, benthic and pelagic habitats in 67 lakes in north-east Germany (ecoregion 14, "Central Lawlands") were fished in a standardized way, literature data on both reference and present fish communities were collected for all 25 lakes in Germany larger than 1,000 ha. In addition, almost 60 parameters describing lake morphology, productivity, shore structure, and land use intensity were recorded. By using a number of multivariate analyses, lakes were grouped according to their fish communities, and the main external structuring factors were derived. Present fish communities were predominantly structured by lake morphology (depth and volume) and productivity (expressed as chlorophyll a content or total phosphorus concentration). The historical and present fish communities in the large lakes differed significantly and the shifts in fish species were mainly attributable to eutrophication. Anthropogenic degradation other than eutrophication had only a little influence on fish community composition. It may be concluded that the fish communities can be used as a tool to evaluate the ecological quality of German lakes as long as eutrophication is considered to be the main anthropogenic impact on the lakes.