Fish diversity in <scp>E</scp>uropean lakes: geographical factors dominate over anthropogenic pressures

Summary We aimed to distinguish the relative contributions of natural and anthropogenic local factors on patterns of fish diversity in E uropean lakes at different geographical scales. We compiled data from standardised fish monitoring using multimesh benthic gill nets, information on lake morphometry and on geographical, climatic and anthropogenic pressure variables from 1632 lakes in 11 E uropean countries. By means of regression trees, we determined those natural and anthropogenic factors and their thresholds that best predicted local fish diversity, density and mean size. Generalised linear models were used to assess the influence of anthropogenic factors at smaller geographical and morphometric scales. Local fish species richness and diversity were related mainly to morphometric and (bio)geographical/climatic variables. Larger and deeper lakes…