phylogenetic diversity and functional diversity

Comparing the phylogenetic diversity (PD; Faith 1992) measure to the Faith (1996) functional trait diversity measure.

Phylogenetic diversity (PD; Faith 1992) predicts patterns of feature diversity, but Faith (1996) suggested an alternative index to better predict functional trait diversity among species.

Faith DP (1996) Conservation Priorities and Phylogenetic Pattern. Conservation Biology, Vol. 10, No. 4 (Aug., 1996), pp. 1286-1289.

Functional traits are broadly interpreted to include any attributes of species that influence their survival and/or influence ecosystem level processes. Biodiversity summaries at the level of functional traits are commonly used to characterise the functional diversity of ecological communities, ecosystems or localities.

An historical review of functional diversity measures (“Quantifying Functional Biodiversity”; Pla et al 2012) refers to the Faith (1996) study: “In the last decade of the twentieth century, Faith (1996) proposed a functional diversity index based on the application of the index of environmental diversity (ED) to a functional space constructed using phylogenetic information.” Faith (1996) drew on “phylogenetic information” in considering  the information left unexplained by the phylogeny – the set of features or traits that showed convergent evolution. He concluded: "The phylogenetic pattern therefore has contributed not only to priorities based on general feature diversity but also to different priorities based on variation in function or habitat".

The original discussion of PD (Faith 1992) foreshadowed the need for this alternative approach:
“In some conservation contexts, representation of convergent features is considered a reasonable goal, because these features correspond to different ecologically functional types... In such cases alternative pattern representations of the taxa (robust ordinations, Faith, 1989) that account for feature variation due to convergence and/or function, and methods for representative sampling of such ordination spaces....may be a useful complement to phylogenetic diversity.” 

see:Quantifying Functional Biodiversity
SpringerBriefs in Environmental Science 2012, pp 27-51 Functional Diversity Indices
Laura Pla, Fernando Casanoves, Julio Di Rienzo


Dr Dan Faith , Senior Principal Research Scientist email:danfaith8[at]
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