Coordinating editor: N. Mason.
Partitioning of functional diversity reveals the scale and extent of trait convergence and divergence
Article first published online: 20 MAY 2009
© 2009 International Association for Vegetation Science
Journal of Vegetation Science
Volume 20, Issue 3, pages 475–486, June 2009
How to Cite
De Bello, F., Thuiller, W., Lepš, J., Choler, P., Clément, J.-C., Macek, P., Sebastià, M.-T. and Lavorel, S. (2009), Partitioning of functional diversity reveals the scale and extent of trait convergence and divergence. Journal of Vegetation Science, 20: 475–486. doi: 10.1111/j.1654-1103.2009.01042.x
- Issue published online: 20 MAY 2009
- Article first published online: 20 MAY 2009
- Received 15 October 2007;Accepted 22 October 2008.
- Alpha and beta diversity;
- Assembly rules;
- Biotic and abiotic filtering;
- Limiting similarity;
- Niche complementarity;
Questions: Trait differentiation among species occurs at different spatial scales within a region. How does the partitioning of functional diversity help to identify different community assembly mechanisms?
Location: Northeastern Spain.
Methods: Functional diversity can be partitioned into within-community (α) and among-communities (β) components, in analogy to Whittaker's classical α and β species diversity concept. In light of ecological null models, we test and discuss two algorithms as a framework to measure α and β functional diversity (the Rao quadratic entropy index and the variance of trait values). Species and trait (specific leaf area) data from pastures under different climatic conditions in NE Spain are used as a case study.
Results: The proposed indices show different mathematical properties but similarly account for the spatial components of functional diversity. For all vegetation types along the climatic gradient, the observed α functional diversity was lower than expected at random, an observation consistent with the hypothesis of trait convergence resulting from habitat filtering. On the other hand, our data exhibited a remarkably higher functional diversity within communities compared to among communities (α≫β). In contrast to the high species turnover, there was a limited functional diversity turnover among communities, and a large part of the trait divergence occurred among coexisting species.
Conclusions: Partitioning functional diversity within and among communities revealed that both trait convergence and divergence occur in the formation of assemblages from the local species pool. A considerable trait convergence exists at the regional scale in spite of changes in species composition, suggesting the existence of ecological redundancy among communities.