There are many reasons conservation biologists might value phylogenetic diversity. One is practical: if closely-related species are more similar than we might expect by chance (phylogenetic signal), phylogenetic diversity can be used as an easy-to measure proxy for functional diversity. Yet the assumptions underlying this motivation have rarely been empirically tested. Another reason to preserve phylogenetic diversity is ideological: preserving sets of species with higher phylogenetic diversity ensures more millions of years of unique evolutionary history will survive. Despite a large body of theory, there are few guidelines available for practitioners who wish to include phylogenetic relationships as a component of conservation prioritization schemes. I describe ongoing work to test the assumption that phylogeny is a proxy for functional diversity, and present preliminary results from a working group organized with the Zoological Society of London (ZSL) about how to best implement phylogenetically-based conservation prioritization.
Preliminary results across multiple taxa suggest that, in some cases, phylogenetic diversity is not a good proxy for functional diversity, despite species' traits exhibiting phylogenetic signal. I describe how this ties in with ongoing theoretical work, and suggest positive ways forward for conservation biologists wishing to effectively use phylogenetic diversity for conservation prioritization. I describe insights gained during discussions with ZSL about how best to incorporate phylogenetic diversity into conservation prioritization. Conservation NGOs have a number of data requirements that academic biologists can work to address, providing a tangible way that we can help make good use of insights gained from existing prioritization research.