Diversity Patterns in Europe

Abstract

With more than 5000 species described, European subterranean biodiversity is the highest in the world. This is in part due to a long history of scientific activities, but some evidence suggests that it is actually higher in Europe due to historical and physiographical factors. The knowledge of European fauna is poorer for subterranean habitats than for any other habitat. In the PASCALIS project, 40% of the stygobiotic faunasampled in seven European sites was shown to be new to science. Several groups radiated extensively in Europe, particularly beetles and Niphargidae amphipods. Subterranean evolution also produced more troglomorphy in Europe than in any other continent.Relictualism is often associated with high troglomorphy, a number of European taxa having no close surface relatives. Cave diversity is unevenly distributed across the continent with a gradient in species richness dropping off to the north, as a result of extinctions due to quaternary glaciations and gradients of primary productivity. Biodiversity peaks on a midlatitude ridge between 42° and 46° north: the major part of European troglobionts, troglomorphic and relicttaxa are on this ridge. On this ridge, two areas contain most of the remarkable cave taxa: the Dinaric range and the Pyrenees. The ratio of troglobionts to stygobionts declines with increasing latitude from the biodiversity ridge. At a finer scale, considerable changes in subterranean communities are linked to habitat characteristics, especially pore size.