Politicians gathering in Nagoya, Japan, for the United Nations' 10th Convention on Biological Diversity — a summit to set conservation goals for 2020 — face grim news: Scientists have reported that one-fifth of Earth's vertebrate species are at risk of extinction.
But the outlook for biodiversity would have been even bleaker without conservation efforts, according to the researchers, whose work was published online Tuesday in the journal Science.
"We've had some successes," said study coauthor Neil A. Cox of the International Union for Conservation of Nature and Conservation International. "Without conservation in place, extinctions would be much worse than they currently are."
The International Union for Conservation of Nature periodically surveys biodiversity worldwide and categorizes species on its so-called Red List based on their extinction risk. The new update compiled data for 25,780 vertebrate species: all mammals, birds, amphibians and cartilaginous fishes — such as sharks — and about 1,500 species each of reptiles and bony fish.
Amphibians are the most endangered, with 30% of species threatened. Of mammals, reptiles and fish, 21% are threatened, as are 12% of birds. On average, 52 species of mammals, birds and amphibians move one category closer to extinction each year, the paper said.
The Red List, which draws on the expertise of about 8,000 scientists, is unusually comprehensive, scientists said. "This is really thorough coverage," said Paul W. Leadley, a professor of ecology at the Universite Paris-Sud 11 in France.
The update includes the Red List's first survey of conservation successes, Cox said. Sixty-eight species — mostly mammals and birds — improved in status, all but four because of conservation efforts such as hunting restrictions and controlling invasive species. Among these: the humpback whale, whose numbers have increased since the introduction of restrictions on whaling, and the California condor, which has rebounded somewhat through a captive breeding and reintroduction program.
But Leadley, who coauthored another biodiversity paper in the same issue of Science, cautioned against placing too much emphasis on efforts to save celebrity species, one by one. "The number of species facing extinction may get to the point that you can't [address] the species individually," he said.
He said broader efforts, including reducing climate change, deforestation and pollution, would be key in the future.
Participants in the Nagoya talks hope to establish conservation goals for 2020. The previous target, for 2010, focused on achieving "a significant reduction of the current rate of biodiversity loss." Though that goal was not met, Cox said, his team's research showed that it still made sense to establish new targets.
"We've missed the target on 2010, but if you invest in conservation, there's gain to be made," he said.