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Quantifying the relevance of intraspecific trait variability for functional diversity
Article first published online: 12 OCT 2010
© 2010 The Authors. Methods in Ecology and Evolution © 2010 British Ecological Society
Methods in Ecology and Evolution
Volume 2, Issue 2, pages 163–174, April 2011
How to Cite
de Bello, F., Lavorel, S., Albert, C. H., Thuiller, W., Grigulis, K., Dolezal, J., Janeček, Š. and Lepš, J. (2011), Quantifying the relevance of intraspecific trait variability for functional diversity. Methods in Ecology and Evolution, 2: 163–174. doi: 10.1111/j.2041-210X.2010.00071.x
- Issue published online: 1 APR 2011
- Article first published online: 12 OCT 2010
- Received 15 December 2009; accepted 14 September 2010 Handling Editor: Robert P. Freckleton
- community dynamics;
- grassland management;
- mass-ratio hypothesis;
- repeated measures;
- trait convergence and divergence;
- trait intraspecific variability;
- variance partitioning
1. Intraspecific trait variability is a crucial, often neglected, component of functional diversity (FD) in ecological communities. In particular, uncertainty remains as to the importance of intraspecific variability in the quantification of FD.
2. To explore this uncertainty, we propose two methods addressing two critical and complementary, but largely unexplored, questions: (i) what is the extent of within- vs. between-species FD in different communities? and (ii) to what extent is the response of FD to environment because of compositional turnover vs. intraspecific trait variability across habitats? The methods proposed to address these questions are built on a variance partitioning approach and have the advantage of including species relative abundance, therefore taking into account species dominance and rarity. For each of the questions, we illustrate one dedicated case study in semi-natural grasslands with associated sampling strategies.
3. The decomposition of total community variance into within- vs. between-species effects can be implemented in a manner similar to the decomposition of quadratic entropy on pairwise individual dissimilarity. The approach can be applied with single and multiple traits, although it proves more informative for single traits. It can prove particularly useful when assessing the role of different sources of trait variability in the assembly of communities.
4. The assessment of the relative contribution of intraspecific trait variability and species turnover to the response of FD to environment is based on a variance partitioning comparing FD indices computed (i) either using individuals measured in a specific habitat alone (FDhabitat) or (ii) all individuals measured across different habitats (FDfixed). This approach provides a more complete understanding of the response of FD to environment.
5. We further propose a guide to apply these two methods and to choose the most suitable method for intraspecific trait measurements. Assessing the role of intraspecific trait variability should allow a more comprehensive understanding of the processes that link species and ecosystems.