Neither species geographic range size, climatic envelope, nor intraspecific leaf trait variability capture habitat specialization in a hyperdiverse Amazonian forest

Abstract

Many plant species exhibit strong association with topographic habitats at local scales. However, the historical biogeographic and physiological drivers of habitat specialization are still poorly understood, and there is a need for relatively easy-to-measure predictors of species habitat niche breadth. Here, we explore whether species geographic range, climatic envelope, or intraspecific variability in leaf traits is related to the degree of habitat specialization in a hyperdiverse tropical tree community in Amazonian Ecuador. Contrary to our expectations, we find no effect of the size of species geographic ranges, the diversity of climate a species experiences across its range, or intraspecific variability in leaf traits in predicting topographic habitat association in the ~300 most common tropical tree species in a 25-ha tropical forest plot. In addition, there was no phylogenetic signal to habitat specialization. We conclude that species geographic range size, climatic niche breadth, and intraspecific variability in leaf traits fail to capture the habitat specialization patterns observed in this highly diverse tropical forest.