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Functional richness, functional evenness and functional divergence: the primary components of functional diversity


  • Norman W. H. Mason,

  • David Mouillot,

  • William G. Lee,

  • J. Bastow Wilson

N. W. H. Mason and J. B. Wilson, Botany Dept, Univ. of Otago, P.O. Box 56, Dunedin, New Zealand ( – D. Mouillot, UMR CNRS-UMII 5119 Ecosystèmes Lagunaires, Université Montpellier II Case 093, FR-34 095 Montpellier Cedex 5, France. – W. G. Lee, Landcare Research, Private Bag 1930, Dunedin, New Zealand.


Functional diversity is hypothesised as being beneficial for ecosystem functions, such as productivity and resistance to invasion. However, a precise definition of functional diversity, and hence a framework for its quantification, have proved elusive. We present a definition based on the analogy of the components of species diversity – richness, evenness and divergence. These concepts are applied to functional characters to give three components of functional diversity – functional richness, functional evenness and functional divergence. We demonstrate how each of these components may be calculated. It is hoped that our definition of functional diversity and its components will aid in elucidation of the mechanisms behind diversity/ecosystem-function relationships.