An index of functional diversity
Version of Record online: 9 APR 2009
2003 IAVS - the International Association of Vegetation Science
Journal of Vegetation Science
Volume 14, Issue 4, pages 571–578, August 2003
How to Cite
Mason, N. W.H., MacGillivray, K., Steel, J. B. and Wilson, J. B. (2003), An index of functional diversity. Journal of Vegetation Science, 14: 571–578. doi: 10.1111/j.1654-1103.2003.tb02184.x
- Issue online: 9 APR 2009
- Version of Record online: 9 APR 2009
- Received 3 January 2002; Revision received 15 October 2002; Final version received 24 February 2003; Accepted 24 February 2003.
- Abundance measure;
- Character evenness;
- Allan (1961);
- Edgar & Connor (2000);
- Webb et al. (1988)
Abstract. Functional diversity has been seen as the key to predicting the stability, invasibility, resource capture, nutrient cycling and productivity of communities. However, it has been unclear how to estimate it. Ten criteria for an index of functional diversity are developed. These include that it should reflect the range of characters present and the abundance of the species with those characters in the community, and be unaffected by the measurement units used or by the number of species.
An index that meets all ten criteria, FDvar, is investigated. It is based on the variance in characters, weighted by the abundance of the species with those characters. Tested with artificial and randomly generated data, it showed reasonable use of the 0 - 1 range (mean 0.60, range 0.0009 - 0.975) and intuitive behaviour. Tested with field data from eight sites in New Zealand, it gave a good spread of values (mean 0.65, range across sites 0.34 - 0.84), showed good ability to distinguish between the communities and its performance was ecologically intuitive. Illustrative correlations are made with mean annual temperature and soil fertility, determined by a bio-assay. FDvar is recommended for general use.