'Mother Lode' Of Gorillas Found In Congo Forests

A group of western lowland gorillas in the Republic of Congo. i i

A group of western lowland gorillas. Thomas Breuer/Wildlife Conservation Society hide caption

itoggle caption Thomas Breuer/Wildlife Conservation Society
A group of western lowland gorillas in the Republic of Congo.

A young male sitatunga shares a feeding patch with a group of western lowland gorillas.

Thomas Breuer/Wildlife Conservation Society
Researcher Jean Robert conducts gorilla nest counts in the Republic of Congo. i i

African researcher Jean Robert conducts gorilla nest counts. Dave Morgan/Wildlife Conservation Society hide caption

itoggle caption Dave Morgan/Wildlife Conservation Society
Researcher Jean Robert conducts gorilla nest counts in the Republic of Congo.

African researcher Jean Robert conducts gorilla nest counts.

Dave Morgan/Wildlife Conservation Society

Gorilla experts with the Wildlife Conservation Society say they've made a spectacular find in isolated forests of the Republic of Congo: a large group of previously undiscovered western lowland gorillas. The animals are critically endangered.

Researchers say the first wildlife census of the area has revealed that 125,000 western lowland gorillas are now thriving in the country's northern forests, a number that is twice some estimates for the worldwide population.

"We have found the mother lode of western lowland gorillas," said Steven Sanderson, president of the society, which led the research. "We had no idea that these great densities, that is numbers per square kilometer [of the gorillas], were possible in central Congo."

The discovery comes even as other gorillas living in central Africa are being pushed toward extinction.

Sanderson says there are few signs that the gorillas in Congo's northern forests have been affected by the problems that have all but wiped out gorilla populations in other parts of Africa — wars, commercial poaching, massive logging operations and disease epidemics linked in part to frequent contact with humans.

"Diseases — led by, but not limited to, the Ebola virus — have created big, empty holes in the forest where gorillas used to be but are no longer," Sanderson said.

One of the main reasons the gorillas have been thriving is obvious to anyone who's ever spent time in the swampy forests that make up what explorers like Richard Ruggiero of the U.S. Fish and Wildlife Service sometimes call the "green abyss."

"You go into it, and it's a world unto itself," said Ruggiero, who wasn't involved in the current research but who has studied gorillas and elephants in central Africa for 15 years.

"These swamp environments are extremely difficult to get along in," Ruggiero said. "There's literally no place to pitch a tent and sleep."

And since there aren't any logging operations in the heart of these northern forests, Ruggiero said, roads are all but nonexistent. That, in turn, has led to low levels of poaching or subsistence hunting. Basically, there aren't many humans here, Ruggiero said.

But that's beginning to change. In recent years, the Republic of Congo has begun to sell the right to log the forests, Ruggiero said. In his view, the pressure to keep selling logging rights is at an all-time high — and it's getting higher.

"Where there are natural resources in Africa, the rush to exploit them is at a pace that no one ever dreamt possible," Ruggiero said.

"It's horrific, frankly. And the value of this announcement of this large population is, hopefully, people will realize that this is a chance to get there before the other guys do," Ruggiero said, referring to hunters and timber companies.

Ruggiero said he now hopes a plan is developed for managing the area's natural resources — a plan, he said, that doesn't include "leaving it up to people with chain saws and bulldozers."

Sanderson said there are ways to protect the gorillas in the "green abyss."

In recent years, his group has helped large logging operations in other parts of Congo learn to harvest trees sustainably and to limit poaching operations that rely on logging roads.

And the government of Congo is considering a plan to turn a big part of this forested area into a wildlife park, Sanderson said.

It'll be difficult and expensive to protect the newly discovered "mother lode," but Sanderson said he thinks it can be done.

A Gorilla Haven, But For How Long?

Unlike mountain gorillas, which number in the hundreds, the western lowland gorilla population is still large enough and inaccessible enough that conservationists do not know its size with any real accuracy.

What conservationists do know is that ape populations are plummeting, decimated by the combined effects of the Ebola virus, commercial hunting and deforestation. The gorillas' ability to recover remains in question, despite recent research led by the Wildlife Conservation Society.

"Ebola has resulted in dramatic local declines in gorilla populations in Congo and Gabon in the last two decades, with population crashes of more than 95 percent being recorded," said Emma Stokes, a scientist with the Wildlife Conservation Society.

"Given the long life spans and slow reproductive cycles of great apes, recent estimates suggest it may take up to 120 years to recover from population crashes of this magnitude," Stokes said.

Threats To The Species

In 2003, a team of scientists reported in Nature that between 1983 and 2000, the ape population in Gabon declined by more than half as a result of commercial hunting and Ebola hemorrhagic fever. They called for gorillas to be listed immediately as critically endangered — a status that means they are expected to suffer a reduction of at least 80 percent in the next three generations. The scientists projected an 80 percent loss in two generations.

Until that point, commercial hunting was considered the most pressing threat to the gorillas' existence. The expanding logging industry had transformed hunting from primarily a subsistence activity into a widespread commercial enterprise, by opening previously inaccessible forest areas to hunters and by providing an infrastructure to transport the bushmeat long distances, reported the scientists.

Between 2003 and 2004, the Zaire strain of the Ebola virus further ravaged the gorilla populations in Gabon and Congo, making the disease as dire a threat as hunting. Scientists in the Lossi Sanctuary in northwest Congo reported in the journal Science that Ebola killed 5,000 gorillas in their study area alone — 90 to 95 percent of the population.

And while commercial hunting is heaviest near human populations, Ebola's scourge is concentrated in remote areas. Observations of ape carcasses that were not slain by hunters spanned 600 km, from west of Booue to the Nouabale–Ndoki region of northern Congo, and was most severe between Lossi and Odzala National Park, the scientists said.

Scientists are able to estimate losses without knowing entire population numbers because losses are generally recorded by measuring changes in gorilla density or numbers in limited areas.

Critically Endangered

The World Conservation Union classified the western lowland gorilla as "critically endangered" in 2007.

It is the most populous of the gorilla subspecies and currently lives in seven countries across western equatorial Africa. Whereas western mountain gorillas can still be counted in the tens of thousands, the eastern lowland gorilla numbers in the thousands and the mountain and cross-river gorilla populations have shrunk to mere hundreds.

The 125,000 apes newly counted in the Wildlife Conservation Society's survey are an enormous boost for the subspecies' chance of survival and for the efforts of conservationists. But the miraculous finding is not without a shadow.

"Ebola is a localized threat to gorilla populations," said Stokes. "These important gorilla populations of 125,000 individuals are adjacent to areas that are known to have been impacted by Ebola outbreaks in recent years."

Although her team's data show that the virus has not yet reached these populations, she said that working quickly to protect this new found mother lode is paramount.

"Until it can be established that the risks from Ebola and hunting are sufficiently reduced or removed across their range," Stokes said, "then western gorillas will remain critically endangered."

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