Disentangling phylogenetic from non-phylogenetic functional structure of bird assemblages in a tropical dry forest
do Nascimento Erivelton Rosário, Correia Isadora, Ruiz-Esparza Juan Manuel, Gouveia Sidney F.
Understanding the factors driving assembling structure of ecological communities remains a fundamental problem in ecology, especially when focusing on ecological and evolutionary relatedness among species rather than on their taxonomic identity. It remains critical though to separate the patterns and drivers of phylogenetic and functional structures, because traits are phylogenetically constrained, but phylogeny alone does not fully reflect trait variability among species. Using birds from the Brazilian dry forest as a study case, we employed two different approaches to decompose functional structure into its components that are shared and non-shared with the phylogenetic structure. We investigated the spatial pattern and environmental hypotheses for these phylogenetically constrained and unconstrained aspects of functional structure, including climate-induced physiological constraints, historical climatic stability, resource availability and habitat partitioning. We found only partial congruence between the two methods of structure decomposition. Still, we found a differential effect of factors on specific components of functional structure of bird assemblages. While climate affects phylogenetically constrained traits through endurance, habitat partitioning (especially forest cover) affects the functional structure that is independent of phylogeny. With this strategy, we were able to decompose the patterns and drivers of the functional structure of birds along a semiarid gradient and showed that the decomposition of the functional structure into its phylogenetic and non-phylogenetic counterparts can offer a more complete portrait of the assembling rules in ecological communities. We claim for a further development and use of this sort of strategy to investigate assembling rules in ecological communities.