SOURCE: Columbia University News and Phys.org

DATE: April 24, 2017

SNIP: A new study indicates that the number of plant and animal species at risk of extinction may be considerably higher than previously thought. A team of researchers, however, believe they’ve come up with a formula that will help paint a more accurate picture.

The study appears in the journal Biological Conservation.

Currently, IUCN makes use of species sightings reported by experts to draw boundaries reflecting the geographic range of a given species. From these maps, the IUCN develops its Red List, which assigns a threat status to wild species: Vulnerable, Endangered, or Critically Endangered. Though the accuracy of threat risk assigned to a species relies heavily on these maps, Melnick and his colleagues believe they almost always overestimate the actual distribution of a species by incorporating areas of unsuitable habitat. This overestimation of range size, in turn, leads to a significant overestimation of population size and therefore an underestimation of extinction risk.