Viernes 17 febrero 2012. 12:05 a 13h.
Salón de Actos. MNCN
(This lecture will be held in English)
Large-scale effects of current and historical climate in the diversity and structure of European assemblages
Speaker: Joaquin Hortal, MNCN.
The geographic patterns of diversity are known to be associated with both current climate and Pleistocene climatic changes. However, the variables describing current and past environmental gradients are spatially correlated, and their relationship with current diversity gradients varies in space. Both characteristics make difficult to disentangle the precise contributions of these factors to the composition and structure of assemblages.
Here I present some results from a working group aiming to determine the roles of current and historical climate on European diversity. First, we assessed the associations of these two factors with the European Scarabaeinae dung beetles, a group with high dispersal ability and well-known adaptations to warm environments. By assessing spatial stationarity in climate variability since the Last Glacial Maximum (LGM) we find that current scarab richness is related to the location of their limits of thermal tolerance during the LGM. These limits mark a strong change in their current species richness–environment relationships and the patterns of species replacement through space. Community phylogenetics analyses show that northern scarab assemblages are nested and composed of a phylogenetically clustered subset of large-range sized generalist species, whereas southern ones are diverse and variable in composition.
These results imply that species responses to current climate are limited by the evolution of assemblages that occupied relatively climatically stable areas during the Pleistocene, and by post-glacial dispersal in those that were strongly affected by glaciations.
We also evaluated the relative importance of the association between species richness and both current climate and the variation of climate since LGM, for nine taxa (mammals, birds, amphibians, reptiles, butterflies, dung beetles, Brassicaceae, Caryophillaceae and trees) throughout Western Europe. The results of these analyses show that richness is generally more strongly associated with long-term variations in climate than with current climate in many parts of Europe, and that the location of these areas is consistent among groups. I finish by discussing some of the forthcoming works of this working group, devoted to determine the impact of glaciations on species replacement and phylogenetic and functional diversity.
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