Deconstructing the mammal species richness pattern in Europe - towards an understanding of the relative importance of climate, biogeographic history, habitat heterogeneity and humans

Aim We deconstructed the mammal species richness pattern in Europe to assess the importance of large-scale gradients in current macroclimate relative to biogeographic history, habitat heterogeneity and human influence (HHH variables) as richness determinants for total species, and for widespread and endemic species separately. Location Europe, west of 30 degrees E. Methods We deconstructed total species richness (50-km resolution) into its widespread and endemic species richness components. We used simultaneous autoregressive modelling (SAR) with information-theoretic model selection and variation partitioning to assess the importance of macroclimate and HHH variables. The HHH variables included two historical factors, estimated by novel methodologies: (1) ice-age-driven dynamics, represented by accessibility to recolonization from hindcasting-estimated glacial refugia, and (2) biogeographic peninsular dynamics, represented by distance to the entry region for the main European faunal source in western Asia. Results A large fraction of explained variation was shared between macroclimate and HHH in the SAR models. For total species richness, more variation could be uniquely attributed to macroclimate than to HHH, whereas for the deconstructed patterns (widespread and endemic species) the opposite was the case. Considering the individual factors, there was a strong peninsula effect on both widespread and endemic species richness but not on total richness. Main conclusions Both macroclimate and HHH variables (history, habitat heterogeneity and human influence) proved important predictors of species richness, but also difficult to disentangle. Notably, biogeographic history, in particular peninsular dynamics, is an important determinant of widespread and endemic species richness.