Detecting biodiversity hotspots using species-area and endemics-area relationships: the case of butterflies

Using data of the Red Data Book of European Butterflies we establish the species-area relationship (S = 8.5 A(0.23)) and the endemics-area relationship (S = 0.5 A(0.18)) of European butterflies. Applying confidence limits as tools for the identification of hotspot countries we show that in the case of butterflies hotspots of endemism and hotspots of overall species richness do not coincide. We introduce plots of residuals from species-area relationships shifted upwards by the 95% confidence limits of the intercept (alpha-values) as a new tool for identifying and ranking of hotspots.