By Paul Rincon
BBC News Online science staff
Numbers of the eastern lowland gorilla have plummeted by more than 70% over the past decade, scientists say.
The lowland gorilla might not last long if the decline continues at its current pace
The researchers have estimated that fewer than 5,000 of the endangered great apes remain in their habitat.
That represents an astonishing drop of 12,000 gorillas since 1994, says the group Conservation International.
War, over-hunting, mining and the spread of humans into the apes' former habitat have placed the species under serious threat it is claimed.
"This decline is massive. But these are also extraordinary circumstances. This is an area that was ravaged by war," Juan Carlos Bonilla, senior director for Central Africa at Conservation International, told BBC News Online.
"There's room for concern and for cautious optimism. There's been an extraordinary response. Never has so much interest centred on this area for conservation," he added.
But if the gorilla's decline continues at the present pace, conservationists agree that it might not be long before it is driven to extinction.
"Gorillas are slow reproducers. This has to be a long-term focus," Dr Patrick Mehlman, director of Africa programmes for Dian Fossey Gorilla Fund International, told BBC News Online.
The eastern lowland gorilla is found almost exclusively in the eastern Democratic Republic of Congo (DRC).
Civil war and mining of the mineral coltan, which is used to make pinhead capacitors in mobile phones and laptops, has brought an influx of people into areas where the apes live. With this often comes a thriving bushmeat trade.
Gorillas are just another victim of the country's civil war
"There's all sorts of things being done, but it's logistically a very difficult place to work," said David Jay, project co-ordinator at the Born Free Foundation.
"Ideally, you wouldn't ban the coltan mining, because it's a very poor area and you don't want to deny people a livelihood. But you want to make sure it's being done in a sustainable way."
A spokeswoman for the International Fund for Animal Welfare (Ifaw) told BBC News Online:
"We and other organisations are working on the bushmeat issue to encourage those countries in which it is a problem to enforce their own laws on the killing and selling of great apes.
"But when the political situation is out of control it's very hard to see how there's going to be any priority put on those laws. It's looking very bleak at the moment."
Maiko National Park in DRC, which is home to many lowland gorillas and has been a protected area since 1938, has had little actual protection according to Conservation International.
The organisation is making an estimated $3m (£1.6m) investment in the Dian Fossey Gorilla Fund International (DFGFI) to strengthen its programme in the region.
Included within this investment is a plan to strengthen protection for the Maiko National Park.
"In eastern Congo, at present, we don't have these huge multinational logging companies building these roads that then become paths for the bushmeat out," said Dr Mehlman.
He added that he wanted to establish projects to get existing communities in the DRC involved with conservation of the gorillas.
"I'm optimistic for the long haul. If community-based conservation projects get in and have the support of the government then 10-15 years down the line populations will become stable again."
Dr Mehlman said he also wanted to develop industries in the area not based on timber. These include banana growing and tourism.
Ebola is another contributing factor to the gorilla's demise. When the gorilla is pushed into ever smaller areas, Ebola and other diseases can spread like wildfire through its population.
A recent survey of mountain gorillas showed their numbers had risen 17% since 1989. It suggested conservation efforts to protect the species from poachers in their remote habitat were paying off.
Eastern Lowland Gorillas are concentrated in the Maiko National park in eastern DR Congo.