The World’s Greatest Apes Are in Grave Danger

The Grauer’s gorilla, the largest member in the great ape family, has experienced a 77 percent population decline since the 1990s, according to a new report from Fauna and Flora International and the Wildlife Conservation Society.

In 1995, an estimated 17,000 Grauer’s gorillas—close relatives to the better-known mountain gorillas—roamed the eastern portion of the Democratic Republic of the Congo, but only 3,800 of them are alive today. The drop in numbers is mainly owing to human conflicts in their native territory, illegal hunting, and habitat loss from increased mining operations, according to the report.

Andrew Plumptre, a Wildlife Conservation Society ecologist and the lead author of the study, said the loss of gorillas degrades ecosystems and reduces a forest’s ability to store carbon.

“Gorillas are important seed dispersers of some trees and also modify the habitat by breaking branches of trees and saplings,” Plumptre said. “When large-bodied seed dispersers such as gorillas and elephants are lost from forests in Africa, the amount of carbon in the forest is lower because they tend to disperse the larger trees and also prune the forest so that trees can grow larger.”

To get accurate gorilla numbers, the team surveyed widespread swaths of historically known Grauer’s gorilla habitat—a region that has shrunk from 15,000 square miles to about 7,300 square miles. Researchers looked for evidence of ground nests and other physical signs of the animals and gathered data from local wildlife rangers to estimate resident gorilla populations.

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Plumptre said the findings confirmed earlier fears from a 2008 estimate, which was based on less data.

To combat the rapid population decline, the study’s authors recommend the Grauer’s gorilla be recategorized as critically endangered by the International Union for Conservation of Nature to increase protections for the species worldwide.

“As one of our closest living relatives, we have a duty to protect this gorilla from extinction,” said Stuart Nixon of Fauna and Flora International, a coauthor of the study. “Unless greater investment and effort is made, we face the very real threat that this incredible primate will disappear from many parts of its range in the next five years. It’s vital that we act fast.”

The gorilla’s initial decline can be traced back to the Rwandan genocide in 1994, which was followed by the Democratic Republic of the Congo’s seven-year civil war. Five million people were killed during the conflicts, and the resulting insecurity led to an increase in illegal bushmeat trade and expansive deforestation.

The vulnerable primates have since been pressured by a new and growing threat: artisanal mining for coltan, a key mineral used in the manufacturing of mobile phones, and other minerals found within the gorilla’s range.

Plumptre said the road to saving Grauer’s gorillas is long, but the decline can be halted. He noted one location, Kahuzi Biega Park, where gorilla conservation efforts have been well funded and security is in place for wildlife rangers in the region.

“We found that gorilla numbers have increased since 2000 there—the only site in the whole survey that showed an increase,” Plumptre said.

The authors of the study laid out six actions to help preserve the surviving Grauer’s gorillas.

1. Establish and enforce boundaries for two known gorilla habitat areas: Itombwe Natural Reserve and Punia Gorilla Reserve. If protected, the areas would preserve 60 percent of the remaining gorilla habitat, only 25 percent of which is protected today.

2. Stop illegal mining inside protected areas, and legally establish artisanal mining cooperatives in areas close to gorilla habitats.

3. Disarm militia groups operating in the region that threaten wildlife rangers.

4. Support park staff and community eco-guards protecting gorillas and their habitat.

5. Find alternative sources of income for local people other than employment from mining.

6. Lobby cell phone, tablet, and computer companies to ensure that source minerals from this region are purchased from mining sites that do not hunt bushmeat and are conflict free.