Two decades of devastating civil war in the Democratic Republic of Congo have prevented scientists from getting to a rainforest area that's home to the Grauer's gorilla, also known as Eastern Lowland Gorillas, to monitor the subspecies' well being.  But new surveys are revealing that primate's numbers have sharply plummeted.

A new report (.pdf link) from the Wildlife Conservation Society (WCS), Flora and Fauna International and the Congolese Institute for the Conservation of Nature says the DR Congo's population of Eastern Lowland Gorillas has dropped 77 to 93 percent.  In 1998, there were an estimated 17,000 of these majestic great apes in the DRC; today there are around 3,800. 

"It is one of the least known apes in terms of its ecology and population due to the existence of armed groups and very poor infrastructure to access gorilla sites,” said Andrew Kirkby, Project Manager for the Wildlife Conservation Society's Grauer's Gorilla Conservation Project.

Since 1959, the country has been plagued with two civil wars, waves of refugees escaping the Rwandan Genocide, high levels of political instability, agricultural expansion, unlicensed mining, as well as illegal logging and hunting - the latter being both for trophies and for bushmeat.  Despite the war being over in 2003, armed groups still roam the country practically unchecked.

The Grauer's Gorillas are the earth's largest primate subspecies, with males frequently growing to 227 kilograms.  But unlike its sister subspecies the Mountain Gorilla which has spread out across the border to Uganda and Rwanda, the Grauer's Gorilla lives only in the DRC's Kahuzi-Biega National Park and surrounding wild areas. 

"The DRC army has been going into the Kahuzi-Biega national park and trying to chase out armed groups," said WCS's Andrew Plumptre.  "But they don’t maintain a long-term presence.  Also, if the army find mining sites, they start managing those sites," he added.

In addition to preserving their habitat and the species, the Wildlife Conservation Society hopes to research how Ebola is transmitted between Gorillas, according to the WCS website.