COS 49-1 - CANCELLED - The influence of environment, phylogeny, and morphology in the assembly of tropical hummingbird communities

Background/Question/Methods

How do traits drive or maintain niche partitioning in Earth’s most diverse environments? In this study we use hummingbirds as a system to examine how morphological diversity, specifically bill shape, facilitates species co-existence in the species-rich communities of the tropics. Recent work has found that both abiotic and biotic factors (e.g. competition) determine the phylogenetic structure of hummingbird communities. Here, we consider how bill shape may further mediate the process of community assembly, using a dataset of hundreds of captures across a range of environments in Antioquia, Colombia. We quantified the morphological and phylogenetic structure for each local community and asked how these structures varied across environments.

Results/Conclusions

Because interspecific competition is thought to be strong in these communities, we predict that the morphological and phylogenetic structure of hummingbird communities will vary predictably with environment. In warm, wet lowland environments, communities are likely to be phylogenetically over-dispersed, while in harsher abiotic environments (e.g., cooler high elevations, or lowland dry forests), communities should show phylogenetic clustering. In each of these communities, the distribution of bill shapes might be predicted by phylogenetic structure and taxonomic scale. In clustered communities bill shape would be over-dispersed at the sub-family level. Conversely, in over-dispered communities, bill shape would tend to be clustered within sub-families. These results would point towards the importance of competition in driving the evolution of niche partitioning in Neotropical hummingbirds.