Taxonomic, phylogenetic and trait betadiversity in South American hummingbirds

Comparison of the taxonomic, phylogenetic and trait dimensions of betadiversity may uncover the mechanisms that generate and maintain biodiversity, such as geographic isolation, environmental filtering, and convergent adaptation. We developed an approach to predict the relationship between environmental and geographic distance and the dimensions of betadiversity. We tested these predictions using hummingbird assemblages in the northern Andes. We expected taxonomic betadiversity to result from recent geographic barriers limiting dispersal, and found that cost-distance, which includes barriers, was a better predictor than Euclidean distance. We expected phylogenetic betadiversity to result from historical connectivity, and found that differences in elevation were the best predictors of phylogenetic betadiversity. We expected high trait betadiversity to result from local adaptation to differing environments, and found that differences in elevation were correlated with trait betadiversity. ...