There is a particular conundrum facing conservation. With an ever-growing list of threatened species but a limited pool of resources, effective conservation action relies on the prioritisation of species and places most at risk of extinction. R. William Stein and a team of researchers, including Nick Dulvy, have identified 21 countries as targets to prioritise for shark, ray and chimaera conservation.
Their paper, published in 2018 in Nature Ecology & Evolution, uses evolutionary distinctiveness – how long ago a species branched off from its nearest neighbour in the evolutionary tree – as a measure to identify the most threatened creatures in our oceans and prioritise them for conservation action. The idea behind evolutionary distinctiveness is that some species have few close living relatives and are evolutionarily unique. These are species that have had more time to evolve differently over the course of evolutionary history. If species with high evolutionary distinctiveness were to go extinct, a proportionally larger amount of evolutionary history would be lost.