National Geographic News
For more than a year, conservationists in equatorial Africa have witnessed an Ebola epidemic burn a deadly trail through great apes at the heart of their range. The lethal virus has felled hundreds of endangered western gorillas and common chimpanzees from populations already devastated by commercial hunting and habitat loss elsewhere on the continent.
Now, in the latest grave news from the region, researchers announced yesterday that numbers of great apes in Gabon have declined by more than half in less than 20 years. Experts fear the decline is even greater outside Gabon and that, unless trends are reversed, great apes could become effectively extinct in as little as two generations.
"This is a catastrophic decline of great apes in an area that contains the bulk of the world's remaining populations," said Peter Walsh, a quantitative ecologist at Princeton University and lead author of the study.
Concerned that standard conservation interventions will not work quickly enough, researchers call for aggressive law enforcement, protected areas management, and Ebola research and intervention measures to slow the rapid decline of great apes. "The other stuff is not working," said Walsh.
Among the countries of western equatorial Africaa region that includes Cameroon, Equatorial Guinea, and the Central African RepublicGabon and the Republic of Congo are considered ecological crown jewels. Tropical forests still cover 80 to 60 percent of the respective countries. Human populations remain relatively low. Last year, Gabon president Omar Bongo established 13 new national parks. The region is home to 80 percent of the world's western gorillas and most of its common chimpanzees. Which makes news of great ape declining fortunes there all the more troubling.
"If chimpanzees and gorillas are in trouble in Gabon, an area known for its pristine, unbroken forests, then we have a species-wide crisis on our hands," Lee White, a Wildlife Conservation Society conservationist who has worked in Gabon for the past decade and study co-author, said in a news release.
The survey warns that unless current trends are reversed, great ape species in the region will decline by another 80 percent in less than 30 years, or two generations, if not sooner, effectively signaling their extinction from Africa.
A 1995 study of great ape numbers in Gabon based population estimates on the percentage of forest cover. The formula failed to account for the impacts of commercial poaching and Ebola epidemics, which felled great ape numbers while leaving forests intact.
Researchers based the new estimate on extensive ground surveys of gorilla and chimpanzee nests in protected and prospective protected areas conducted between 1998 and 2002. Their analysis also factored in regional proximity to cities and incidences of human Ebola outbreaks.
The new study confirms what wildlife experts on the ground have long suspected and provides the first accurate handle on their true numbers, said Rebecca Kormos, a research fellow with the Center for Applied Biodiversity Science at Conservation International, in Washington, D.C.
"A lot of deaths from the Ebola epidemic have occurred since this survey was finished, and it's done a lot of damage," said Walsh. "The situation is even worse than those numbers say."
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