Current climate, but also long‐term climate changes and human impacts, determine the geographic distribution of European mammal diversity

Aim: Historical climate variations, current climate and human impacts are known to influence current species richness, but their effects on phylogenetic and trait diversity have been seldom studied. We investigated the relationship of these three factors with the independent variations of species, phylogenetic and trait diversity of European mammals. Considering the position of the 0 ºC isotherm in the Last Glacial Maximum as a tipping point, we tested the following hypotheses: northern European assemblages host fewer species than southern European ones; northern areas harbour trait and phylogenetically clustered assemblages, while the more stable southern areas host random or overdispersed assemblages; and species richness correlates positively with human influence, while phylogenetic and trait diversity show clustered patterns in areas with stronger human influence. Location: Western Palaearctic. Time period: Current and Late Pleistocene effects on present-day diversity. Major taxa studied: Terrestrial mammals. Methods: We used a novel analytical approach based on distance matrices to separate the independent variations of species, phylogenetic and trait diversity, and assessed their relationships with current climate, climate stability and human influence through structural equation models. Results: The species-poor assemblages from northern Europe show higher phylogenetic and trait clustering than the more stable richer southern areas. However, no assemblage presented trait or phylogenetic overdispersion. Current climate is the primary driver of phylogenetic and trait diversity, while species richness is affected similarly by both current and past climates. Higher human influence correlates positively with species richness and trait diversity, both directly and by mediating indirect effects of present climate. Main conclusions: Current climate, climate stability and human influence affect the studied aspects of diversity, although the form and magnitude of their effects vary through space. Importantly, higher levels of human disturbances correlate with more species rich and trait diverse assemblages, an apparently counterintuitive result that deserves further study.

info:eu-repo/semantics/publishedVersion