Local-scale Partitioning of Functional and Phylogenetic Beta Diversity in a Tropical Tree Assemblage.

Jie Yang,Nathan G Swenson,Guocheng Zhang,Jie Li,Xiuqin Ci,Liqing Sha,Luxiang Lin,J W Ferry Slik,Min Cao

doi:10.1038/srep12731

Abstract

The relative degree to which stochastic and deterministic processes underpin community assembly is a central problem in ecology. Quantifying local-scale phylogenetic and functional beta diversity may shed new light on this problem. We used species distribution, soil, trait and phylogenetic data to quantify whether environmental distance, geographic distance or their combination are the strongest predictors of phylogenetic and functional beta diversity on local scales in a 20-ha tropical seasonal rainforest dynamics plot in southwest China. The patterns of phylogenetic and functional beta diversity were generally consistent. The phylogenetic and functional dissimilarity between subplots (10 × 10 m, 20 × 20 m, 50 × 50 m and 100 × 100 m) was often higher than that expected by chance. The turnover of lineages and species function within habitats was generally slower than that across habitats. Partitioning the variation in phylogenetic and functional beta diversity showed that environmental distance was generally a better predictor of beta diversity than geographic distance thereby lending relatively more support for deterministic environmental filtering over stochastic processes. Overall, our results highlight that deterministic processes play a stronger role than stochastic processes in structuring community composition in this diverse assemblage of tropical trees.

Highlights

Beta diversity represents the compositional differentiation between species assemblages
A clear early example of this comes from Fukami et al.[21] who found that experimental plant communities may functionally converge through time while maintaining divergent species compositions indicating the importance of functional determinism
The present study focused on quantifying the phylogenetic and functional beta diversity and partitioning their variation along environmental and spatial gradients at multiple spatial scales in a Chinese tropical forest

Summary

Introduction

Beta diversity represents the compositional differentiation between species assemblages. Recent conceptual advances have been made using patterns of beta diversity to disentangle the relative importance of stochastic and deterministic processes during community assembly[4,5,6,7]. A deterministic model, that assumes the importance of ecological interactions with the environment, predicts that environmental distance will be the best predictor of species beta diversity. Partitioning beta diversity into environmental and geographic components provides a useful tool for disentangling the relative importance of deterministic or neutral processes in community assembly[11]. While beta diversity approaches have been widespread, they have largely focused on the species turnover or dissimilarity between assemblages[4,5,7,11] Such an approach assumes that all species independent, ignoring the functional and phylogenetic differences between them[12,13]. Local-scale investigations integrating both phylogenetic and functional turnover have been rare[24,27,28], despite the large number of papers on phylogenetic and functional alpha diversity in plant communities[29,30,31]

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Conclusion