For lakes, cause-effect relationships are based on phosphorus (P) and nitrogen (N) loadings. Eutrophication is generally considered a good indicator of land use intensity in the lake’s catchment, and the effects of eutrophication on lake biota are rather well studied.
Literature data from about 20 studies on biodiversity related to P and N were combined and fitted by logistic regression. Cause-effect relationships were established separately for deep and shallow lakes. The results indicate a 50% MSA loss at total phosphorus concentrations around 0.1 mg/l for shallow lakes and 0.03 mg/l for deep lakes.