Patterns and processes in the distribution of European centipedes (Chilopoda)

Abstract

Aim: To identify consistent biogeographical modules, and examine species diversity and distribution patterns of centipede assemblages. Location: Europe, including Turkey and Macaronesia. Methods: A dataset was compiled, detailing the occurrence of 585 species of centipedes in 56 countries. Cluster analysis using UPGMA (unweighted pair-group method with arithmetic averages) was used to identify biogeographical modules. To cope with potential issues resulting from the use of political geographical entities, the robustness of the modules was tested using two different randomization approaches. Potential centres of diversity and dispersal for the taxa were hypothesized using two different approaches, based on nestedness analysis using NODF and on investigation of species diversity gradients, respectively. Results: The Mediterranean region was found to be the most species-rich area. Cluster analysis identified four major biogeographical modules, namely Eastern Mediterranean, Western Mediterranean, Balkan Peninsula with eastern-central Europe, and north-western Europe. The robustness of these modules was supported by two randomization approaches. Both the analysis of nestedness and of species diversity gradients consistently identified the Balkan Peninsula as a potential centre of diversity for centipedes in Europe. Main conclusions: The arrangement of the centipede fauna into four biogeographical modules is consistent with European topography and environmental heterogeneity, with high mountain ranges acting as dispersal barriers, limiting the species overlap between modules. Common palaeogeographical history may explain the high degree of nestedness observed in the central and north-western European modules, whereas the high number of singletons and endemics is responsible for the low degree of nestedness in southern Europe. The identification of the Balkan Peninsula as a potential centre of diversity is in agreement with its high environmental heterogeneity and its known role as a Pleistocene glacial refugium.