Phylogenetic diversity is a
measure of biodiversity which incorporates
phylogenetic
In biology, phylogenetics (; from Greek φυλή/ φῦλον [] "tribe, clan, race", and wikt:γενετικός, γενετικός [] "origin, source, birth") is the study of the evolutionary history and relationships among or within groups o ...
difference between species. It is defined and calculated as "the sum of the lengths of all those branches that are members of the corresponding
minimum spanning path", in which 'branch' is a segment of a
cladogram
A cladogram (from Greek ''clados'' "branch" and ''gramma'' "character") is a diagram used in cladistics to show relations among organisms. A cladogram is not, however, an evolutionary tree because it does not show how ancestors are related to d ...
, and the minimum spanning path is the minimum distance between the two nodes.
This definition is distinct from earlier measures which attempted to incorporate phylogenetic diversity into
conservation planning, such as the measure of 'taxic diversity' introduced by Vane-Wright, Humphries, and William.
The concept of phylogenetic diversity has been rapidly adopted in conservation planning, with programs such as the
Zoological Society of London
The Zoological Society of London (ZSL) is a charity devoted to the worldwide conservation of animals and their habitats. It was founded in 1826. Since 1828, it has maintained the London Zoo, and since 1931 Whipsnade Park.
History
On 29 ...
's
EDGE of Existence programme
The ''EDGE of Existence programme'' is a research and conservation initiative that focuses on species deemed to be the world’s most "Evolutionarily Distinct and Globally Endangered" (EDGE). Developed by the Zoological Society of London (ZSL), the ...
focused on evolutionary distinct species. Similarly, the
WWF's
Global 200
The Global 200 is the list of ecoregions identified by the World Wide Fund for Nature ( WWF), the global conservation organization, as priorities for conservation. According to WWF, an ecoregion is defined as a "relatively large unit of land or w ...
also includes unusual evolutionary phenomena in their criteria for selecting target
ecoregion
An ecoregion (ecological region) or ecozone (ecological zone) is an ecologically and geographically defined area that is smaller than a bioregion, which in turn is smaller than a biogeographic realm. Ecoregions cover relatively large areas of l ...
s.
Some studies have indicated that
alpha diversity is a good proxy for phylogenetic diversity, so suggesting that term has little use, but a study in the
Cape Floristic Region showed that while phylogenetic and species/genus diversity are very strongly correlated (R2 = 0.77 and 0.96, respectively), using phylogenetic diversity led to selection of different conservation priorities than using species richness. It also demonstrated that PD led to greater preservation of 'feature diversity' than species richness alone.
[Forest, F. et al. 2007. Preserving the evolutionary potential of floras in biodiversity hotspots. Nature 445, 757-760 http://www.nature.com/nature/journal/v445/n7129/full/nature05587.html]
References
{{Reflist
Measurement of biodiversity