Phil. Trans. R. Soc. B 370, 20140010 (2015)

Credit: DANWEI HUANG

Climate change, alongside human impacts, is increasing the extinction risk of reef corals. A third of reef-building corals are threatened, and the loss of these species would reduce the evolutionary diversity of reefs. To prioritize conservation efforts that would maintain such diversity, information is needed at a regional level.

Danwei Huang, of National University of Singapore, and Kaustuv Roy, of the University of California, San Diego, USA, use two metrics of evolutionary diversity — phylogenetic diversity (representing the amount of evolutionary history present) and phylogenetic species variability (a measure of the level of evolutionary redundancy). Combining these with the geographic distributions of 842 reef-building corals they investigate ecoregions at risk of losing evolutionary diversity.

The two measures give different results on the regional scale, highlighting the need to consider multiple metrics in risk assessments. The authors report that regions that are species-rich are at lower risk of losing a substantial amount of their evolutionary diversity, whilst regions with fewer species are at a higher risk and should be prioritized for conservation. This is counter to current practices, where species-rich areas are often favoured due to the potential loss of a large number of species.