More than 200 bird species in six rapidly developing regions are at risk of extinction despite not being included on the International Union for Conservation of Nature (IUCN) Red List of at-risk species, according to a new study.
Researchers at Duke University in the US used remote sensing data to map recent land-use changes that are reducing suitable habitat for more than 600 bird species in the Atlantic forest of Brazil, Central America, the western Andes of Colombia, Sumatra, Madagascar and Southeast Asia.
Out of these 600 species, only 108 are currently classified by the IUCN Red List as being at risk of extinction.
The new analysis, however, shows that 210 of the species face accelerated risks of extinction and 189 of them should now be classified as threatened, based on the extent and pace of habitat loss documented by recent remote sensing.
"Good as it is, the Red List assessment process dates back 25 years and does not make use of advances in geospatial technologies," said Stuart L Pimm from Duke University.
"We have powerful new tools at our fingertips, including vastly improved digital maps, regular global assessments of land use changes from satellite images, and maps showing which areas of the planet are protected by national parks," he said.
By not incorporating this type of modern geospatial data directly into its assessments, Pimm said, the Red List is underestimating the number of species at risk and causing scientists and policymakers to overlook priority areas for conservation.
"The Red List employs rigorously objective criteria, is transparent, and democratic in soliciting comments on species decisions," he said.
For instance, while the Red List currently includes estimates of the size of a specie's geographical range in its assessment process, it fails to account for how much preferred habitat remains within that range, said lead author Natalia Ocampo-Penuela, who received her PhD from Duke this year.
"Some bird species prefer forests at mid-elevations, while others inhabit moist lowland forests," she said.
"Knowing how much of this preferred habitat remains - and how much of it has been destroyed or degraded - is vital for accurately assessing extinction risks, especially for species that have small geographical ranges to begin with. But it Is ignored in the current Red List assessment process," she said.
"When these factors are accounted for, some species that are not currently considered at risk of extinction likely have ranges that are smaller than those that the Red List otherwise quite sensibly decides are at risk," said Clinton Jenkins, who directs a biodiversity mapping site.
"Natural habitats in the most bio-diverse places on Earth are disappearing, pushing species towards extinction a thousand times faster than their natural rates," said Ocampo-Penuela.
"Preventing these extinctions requires knowing what species are at risk and where they live," she said.
The study was published in the journal Science Advances.