ICES Journal of Marine Science: Journal du Conseil Advance Access originally published online on July 29, 2008
ICES Journal of Marine Science: Journal du Conseil 2008 65(8):1462-1468; doi:10.1093/icesjms/fsn118
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This article appears in the following ICES Journal of Marine Science issue: Marine Environmental Indicators: Utility in Meeting Regulatory Needs [View the issue table of contents]
Average functional distinctness as a measure of the composition of assemblages
1 Plymouth Marine Laboratory, Prospect Place, Plymouth PL1 3DH, UK
2 Department of Biological Science, Simon Fraser University, Burnaby, BC, Canada V5A 1SA
Correspondence to P. J. Somerfield: tel: +44 1752 633100; fax: +44 1752 633101; e-mail: pjso{at}pml.ac.uk
Somerfield, P. J., Clarke, K. R., Warwick, R. M., and Dulvy, N. K. 2008. Average functional distinctness as a measure of the composition of assemblages. – ICES Journal of Marine Science, 65: 1462–1468.Indices are used to quantify change in the environment by reducing aspects of environmental complexity to numbers. Biodiversity indices are typically calculated using the numbers of species and their relative abundances. A recent advance has been the development of additional measures of diversity, such as phylogenetic diversity, based on relationships between organisms. The emerging paradigms of the importance of biodiversity to ecosystem services and the ecosystem approach to fishery management could be well served by the development of indicators of ecosystem functioning. We discuss how relatedness measures may be adapted to quantify aspects of community structure of relevance to ecosystem functioning, by combining information on species occurrence, life history, and ecological traits. We present an index that reflects average functional distinctness within assemblages. We illustrate the approach using North Sea fish. Results reveal that average functional distinctness is not independent of taxonomic distinctness. This is expected, but the weakness of the relationship suggests that both indices may prove useful, because they are not constrained to convey the same information about samples. Both indices are shown to be weakly related to species richness, which was not expected. This is a consequence of differences in the frequencies of occurrence among species.
Keywords: biodiversity, functional distinctness, marine, monitoring, relatedness, taxonomic distinctness
Received 23 November 2007; accepted 21 May 2008; advance access publication 29 July 2008.