Species distributions, assemblage composition, and species richness depend on both current environment and the diversification of lineages in past environments. On broad scales, processes that constrain diversifying lineages to certain regions or environments are particularly important. Through species pool effects, those processes also affect local community composition and richness. In addition, evolution directly affects local communities directly via niche-based assembly. We studied these effects with palms (Arecaceae) as a model group, using a) a dataset including >340,000 palm individuals in 430 transects in the Western Amazon, b) a set of range maps for all American palms (550 spp.), and c) global country-level presence/ absence data of all (>2400) palm species. These data were analysed with novel phylogenetic community structure and turnover methods. Globally, the phylogenetic structure of palm assemblages reflects several biogeographic and evolutionary processes. In the Americas, both dispersal limitation and a phylogenetically conserved temperature niche have constrained the evolution of palm species ranges. Broad-scale processes also influenced the local phylogenetic structure of Amazonian palm communities, which mainly reflects the evolution of habitat preferences.
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Botanikertagung 2011 - Diversity makes the difference