Climate-Niche Evolution in Leaf-Warblers (Aves: Phylloscopidae): A Matter of Phylogeny

Macroevolutionary studies which focus on the development of traits in a phylogenetic context are increasingly used to explore the evolutionary mechanisms and processes that have led to the diversity in species we see today. This includes the study of the evolution of climatic niches within taxonomic groups. Here, we used the leaf-warbler family (Aves: Phylloscopidae) and two dated phylogenetic trees on this group to assess how phylogenetic trees can affect results on the evolution of climatic niches. Trees applied differ in numbers of extant species and in species’ divergence times. We established ecological niche models from climate and occurrence data for all species represented in these trees and calculated predicted niche occupancies (PNOs) and ancestral niches for each of the two trees. Additionally, we examined the niche overlap and deviations from a Brownian motion model for each tree by assessing the accumulation of disparity through time, the strength of the phylogenetic signal and the best-fitting evolutionary model for different niche dimensions. We found differences in the evolutionary history of PNOs for the two phylogenetic trees. The accumulation of disparity through time, phylogenetic signal and mode of evolution of different climatic variables also differed when using the two trees and even suggested contrary interpretations. Our results indicate that the phylogenetic tree applied could strongly influence the outcome of similar macroevolutionary studies and recommend caution for their interpretation.