Historical climatic variability and geographical barriers as drivers of community composition in a biodiversity hotspot

Aim: To evaluate the roles of Quaternary (< 2.6 Ma) climatic stability and geologic barriers (i.e. the Andes Mountains) in shaping the modern community composition and patterns of endemism in Neotropical dry forest bird communities. Location: Marañón Valley and Tumbes, north-western Peru. Methods: We recorded presence and abundance of species in six dry forest bird communities on either side of the Andes Mountains. We used the data to calculate the beta diversity and phylogenetic beta diversity across regional and local scales. We compared the observed results to randomly permuted communities to determine if the communities were significantly more or less similar than we would expect by chance. Mantel tests evaluated whether beta diversity and phylogenetic beta diversity measures were correlated and whether there was a correlation between spatial distance and community diversity. Results: Bird community composition, including abundance, is highly heterogeneous in north-western Peru, ...