Functional Traits and Niche-Based Tree Community Assembly in an Amazonian Forest

TLDR

It is debated whether species‑level differences in ecological strategy, which play a key role in coexistence theory, are important in structuring highly diverse communities. The study examined co‑occurrence patterns of over 1100 tree species in a 25‑hectare Amazonian forest plot to assess the influence of functional traits. The authors analyzed these patterns using field‑measured functional traits. Using a null model, the authors found that co‑occurring trees are often less ecologically similar than predicted by a neutral model, and evidence of both convergence and divergence processes suggests at least two distinct niche‑based mechanisms that contribute to maintaining diversity in this tropical forest.

Abstract

It is debated whether species-level differences in ecological strategy, which play a key role in much of coexistence theory, are important in structuring highly diverse communities. We examined the co-occurrence patterns of over 1100 tree species in a 25-hectare Amazonian forest plot in relation to field-measured functional traits. Using a null model approach, we show that co-occurring trees are often less ecologically similar than a niche-free (neutral) model predicts. Furthermore, we find evidence for processes that simultaneously drive convergence and divergence in key aspects of plant strategy, suggesting that at least two distinct niche-based processes are occurring. Our results show that strategy differentiation among species contributes to the maintenance of diversity in one of the most diverse tropical forests in the world.