European hotspots as evidenced by the Palearctic distribution of songbirds

A database has been created of digitized equal area distribution maps of 2,401 phylogenetic species of songbirds endemic to the Palearctic Region. Geographic distribution of species richness delineated several hotspot regions in the Palearctic, mostly located in mountainous areas. The index of range-size rarity generally identified similar hotspot regions as that for species richness, although it de-emphasized the large central-Siberian hotspot. The hypothesis was tested that databases restricted to a non-natural biogeographic region, such as "Europe," will identify a different set of hotspots, as compared with a spatial analysis of a more natural biogeographic region such as the Palearctic. For that purpose, only those taxa from the dataset were selected that occur in the geographic region delimited by the EBCC atlas and the Climatic Atlas of European Breeding Birds, in total 516 taxa. European hotspots of species richness were slightly more prominent in the Palearctic dataset as compared with the European dataset of 516 taxa. The index of range-size rarity indicated a more pronounced difference between the hotspots identified by the Palearctic dataset and the European dataset, with little or no differentiation in the latter. It is concluded that the present qualitative analysis suggests that it is important for hotspot and conservation studies to examine a natural biogeographic region, and not a geopolitical entity such as "Europe."