Phylogenetic Diversity and Endemism: Metrics for Identifying Critical Regions of Conifer Conservation in Australia

Abstract

Accurately and sufficiently quantifying biodiversity is integral for conservation. Traditional metrics for measuring biodiversity, species richness (SR) and weighted endemism (WE), do not take into account the evolutionary history of organisms. Phylogenetic diversity (PD) addresses the shortcomings of SR by quantifying the evolutionary connections among the species present in an area. Phylogenetic endemism (PE) addresses the shortcomings of WE and represents the ranges of the branches of the evolutionary tree connecting the species in an area. Australia, with its advanced digitization of spatial reference data is the best model system for quantitative studies of biodiversity at present. I created a phylogeny for the 39 indigenous Australian conifer species using matK and rbcL sequences from GenBank and sequencing the 4 species for which there were no existing data. I used spatial data from Australia’s Virtual Herbarium and removed records of conifers that were not naturally-occurring. I then used Biodiverse v 0.17 to calculate PD, PE and two derived metrics, Relative Phylogenetic Diversity (RPD) and Relative Phylogenetic Endemism (RPE). These metrics identify regions with statistically significantly high or low levels of PD and PE based on randomization tests. The results show that conifer RPD is significantly low on the Northeast coast of Australia, although conifer PD is high in the same region. RPE is significantly high along the Northeast coast, in the same region that RPD is low. Most of these regions are currently encompassed by legally protected Australian Reserves. More precise estimates of biodiversity can be used by conservation policy-makers.