Patterns of endemism in riverine fish of the Northern Hemisphere

Loss of endemic species represents a symptom of general degrading ecosystem conditions that is the indirect result of biodiversity alteration. Here, w e developed a predictive model relating species richness of endemic riverin e fishes to measured biological, climatic, and historical variables using d ata from 118 rivers distributed all over the Northern Hemisphere. In a mini mally adequate multiple general least square model, total riverine fish spe cies richness, historical biogeography (Pleistocene glaciations), and comte mporary climate accounted for 63% of the variability in endemic species ric hness; the strongest correlate being riverine fish species richness. Our fi ndings suggest that (i) endemism and richness patterns are generally simila r (fish diversity "hot-spots" areas sustain higher endemic species richness ); (ii) glaciation in the Pleistocene have had a significant negative influ ence on endemic species richness in the more septentrional areas; and (iii) certain basins situated in desertic areas (subtropical dry-zone of deserts ) have unusually high numbers of endemics. These last areas should not be o vershadowed when setting conservation priorities.