Rethinking Extinction Risks

Reducing rates of extinction represents one of the greatest ecological challenges of our time. Over the past few years, the International Union for Conservation of Nature has published Red Lists documenting the inexorable slide towards extinction of species; recent losses include the Hawaiian crow, golden toad, Baiji dolphin, and the West African black rhino. In groups we know well, such as mammals, the risk of extinction has been related to biology, with the most vulnerable species tending to be large, slow breeding, and narrowly distributed. Although plants are the basis for life on Earth, our knowledge of the drivers of plant extinctions is poor.

In this new study on plants, we show that the processes of extinction and speciation [the evolutionary process by which new species arise] are linked. The most vulnerable species are found within young and fast-evolving plant lineages, opposite to patterns in vertebrates. Our results have important implications for conservation priorities and suggest that we might have to rethink the criteria we use to assess extinction risks in plants, where detailed data on species' declines is difficult to obtain.