Ebola Spurs Fears of Looming Ape Extinction

Sean Markey
National Geographic News
April 7, 2003
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 Africa—a region that includes Cameroon, Equatorial Guinea, and the Central African Republic—Gabon 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.

Counting Nests

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."

Researchers noted that populations have not declined by 56 percent across the board. "What's left now is sort of islands of gorillas and chimpanzees…and other areas where they've been wiped out completely," said Walsh.

The survey noted that ape densities declined by 99 percent in the Minkébe forest of northern Gabon in the last decade. Ebola was the likely cause.

"It's mind-boggling how bad this news is," John Robinson, a senior vice president of international conservation programs with Wildlife Conservation Society, said in a news release.

Guns and Guards

Habitat lost to logging and agriculture once posed the greatest single threat to great apes in Africa. But commercial hunting and Ebola have leap-frogged to the fore in recent years.

Africa confronts a growing crisis in the bush meat trade. Commercial hunters using snares and guns strip an estimated one million tons of wildlife from forests to supply logging camps and distant cities with smoked bush meat. Trade has grown into a U.S. $1 billion-a-year industry.

While Gabon does have a crack, national anti-poaching team, it is too small and under funded to grapple with the scope of the country's bush meat problem, Walsh said. To intervene effectively, arming park guards, conducting regular anti-poaching patrols, establishing road blocks and vehicle searches, and searching trains and airlines for smuggled bush meat are necessary steps, Walsh said.

Other wildlife experts agree. "I think there are many different solutions, not just guns and guards. But that's also part of it," said Kormos, a great ape expert who has spent five years working in Gabon and Equatorial Guinea. "Because at the end of the day you have to make a decision. If these species are really going to disappear because of bush meat hunting, well sometimes fairly strong actions are needed."

While controversial, similar law enforcement measures have proven effective elsewhere in Africa. In the 1980s the Kenyan government armed Kenyan Wildlife Service guards with semiautomatic G-3 rifles and shoot on sight authority to battle ivory poachers who killed close to 80 percent of the country's wild elephants and black rhinos in just two decades. Tanzania, Botswana, Namibia and, more recently, the Central African Republic have enforced similar programs.

Meanwhile, commercial logging companies still routinely cut inside park boundaries in Gabon, Walsh said. Enforced park borders, park management plans, budgets, and other protected area management strategies are needed, he said.

National park systems and wildlife agencies in many African countries often lack basic resources to deal with complex problems facing them. "They're highly underfunded. Park guards have very little resources, very little training. And conservation staff from international conservation organizations often can't provide the support that they need to," said Kormos.

Ebola Outbreak

How to intervene in the Ebola outbreak sweeping through great apes in the region poses a thornier issue.

An outbreak in Gabon a decade ago may have killed thousands of gorillas and chimpanzees, according to the Wildlife Conservation Society.

The latest epidemic, most visible in Congo's Lossi sanctuary and now approaching gorilla-dense Odzala National Park, has spread like wildfire through 100,000 square kilometers (38,600 square miles) and shows no sign of slowing down, according to Walsh.

The crisis has highlighted some disagreement within scientific circles as to the origins and true nature of the Ebola epidemic and what steps, if any, can be taken to arrest its spread.

Scientists are still seeking answers to such basic questions about where Ebola hides, how is it transmitted, and whether growing incidents of the disease is the result of human ecological change, as most commonly believed, or a spatial epidemic.

Those answers will ultimately determine what course of action to take. Is there little to do but watch disease burn itself out? Or can more aggressive measures, such as constructing epidemic "firebreaks" along rivers and roads, developing vaccination programs, relocating healthy animals, and culling the reservoir hosts of the virus, be taken?

Walsh and other paper authors demand that U.S. $10 million be immediately added to the budget of the U.S. Fish and Wildlife Service Great Ape Fund for Ebola research and prevention.

They've also requested that the World Conservation Union upgrade western gorilla and common chimpanzees from "endangered" to "critically endangered" status.

Top researchers in human and ape Ebola met late last month in Brazzaville, Congo, to discuss the unfolding crisis. A second meeting hosted by Conservation International will be held in Washington, D.C. late next month.

"The idea that this is just a bunch of crazy environmentalists who only care about gorillas and chimpanzees is misplaced," said Walsh. "Our ability to understand the ecological dynamics of emerging disease is absolutely fundamental to preventing those emerging diseases from devastating humans, both in the remote places in the developing world and in the developed world—United States underlined."

A summary of the research appears in the current online edition of the science journal Nature.

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