Third more wild gorillas than previously thought, major study finds

There are far more gorillas left in the world than previously believed, according to a major new study.

At least 361,900 western lowland gorillas remain in the wild, a third more than previous estimates, a landmark 10-year survey found.

However, they remain critically endangered, with their population falling by more than 20 per cent in eight years.

Eighty per cent of the remaining gorillas exist outside of protected areas, researchers added, making them especially vulnerable to poaching and habitat loss.

The scientists carried out foot surveys spanning 72,000 square miles of western equatorial Africa, including some of the world’s most remote forests.

Researchers walked more than 5,400 miles in total, collecting data on 20,000 nests of western lowland gorillas, which are by far the most widespread and numerous subspecies of the great ape.

Although the majority were found outside protected areas, they were all in forests close to or bordering national parks and nature reserves away from human activity, suggesting conservation efforts will be key to their survival.

The greatest threats to gorillas are illegal hunting, habitat degradation and disease – particularly ebola, which has decimated their numbers in recent years.

“All great apes, whether in Africa or Asia, are threatened by poaching, especially for the bushmeat trade,” said David Greer, co-ordinator of African great apes programme at WWF, one of eight organisations involved in the survey.

“Our study found that apes could live in safety, and thus in higher numbers, at guarded sites.”

The International Union for the Conservation of Nature (IUCN), which compiles a “red list” of critically endangered species, had estimated there were between 150,000 and 250,000 lowland gorillas in west Africa.

The new figure was compiled using data from areas not previously not surveyed, as well as improved methodology, said the researchers involved.

The scientists also assessed the population of central chimpanzees, a subspecies native to the same range. Their numbers were put at 130,000, around a tenth higher than previously thought.

“It’s great news that the forests of western equatorial Africa still contain hundreds of thousands of gorillas and chimpanzees, but we’re also concerned that so many of these primates are outside of protected areas and vulnerable to poachers, disease, and habitat degradation and loss,” said lead author Samantha Strindberg, a scientist at the Wildlife Conservation Society.

She added: “These findings can help inform national and regional management strategies that safeguard the remaining habitat, increase anti-poaching efforts, and curtail the effects of development on great apes and other wildlife.”

While the new estimated gorilla population is far higher than previously thought, it remains considerably lower than the IUCN's 2005 assessment, in which 450,000 were thought to remain in the world.

At the current rate of loss, 80 per cent of gorillas will have gone by the end of the century, said University of Illinois primate expert Paul Garber, who was not part of the study but praised it.

“That is a doomsday scenario, and we need to reverse this immediately,” he added.

Said Hjalmar Kuhl, of the Max Planck Institute for Evolutionary Anthropology, which was involved in the research, said: “Protecting our gorillas and chimpanzees will… require a major increase in political will at all levels—national, regional, and global.

“Financial commitments from governments, international agencies for endangered species conservation and the private sector, are also critical for conserving our closest relatives and their habitats.”