VIRUNGA NATIONAL PARK, Congo - Not far from a hillside where several mountain gorillas shot dead last summer lie buried, park ranger Innocent Mburanumwe peers across a primordial canopy of treetops into what may be the most dangerous game reserve on earth.
The lush sanctuary - home to some of the world's last mountain gorillas - was thrust onto the front lines of Congo's latest war in September. Since then, the fragile habitat in the Central African highlands has been overrun by rebels and soldiers, transformed into an off-limits war zone.
In the world of wildlife conservation, the biggest worry most rangers face is the extinction of endangered animals. But in Virunga National Park, where more than 120 rangers have been killed over the last decade, they also worry about their own survival.
In recent months, some have dodged bullets while driving in their cars. Some have spent nights hiding under beds with their families. All were forced to flee the park's so-called gorilla sector when rebels swept in, some taking shelter in tents on the sanctuary's edge.
"There are undoubtedly risks associated with this job," says Mburanumwe, 35, whose brother - also a ranger - was killed in the line of duty a decade ago. "But our concern is for the gorillas. That's the reason we're here."
The gorillas have the potential to draw tourist revenue to a desperately poor region and bring in vital funding through conservation groups. Over the last 12 months, though, rangers have watched helplessly as the gorillas have been massacred.
Last year was the apes' bloodiest year on record since famed American researcher Dian Fossey first began working in Congo in the mid-1960s to save them. The toll: 10 shot and killed, two others missing. The rangers don't know for sure who killed the gorillas, but they believe illegal charcoal traders are trying to sabotage the park for easier access to its trees.
Now armed groups have seized the habitat. With park staff unable to set foot inside the reserve for the last four months, the gorillas' fate is unknown.
"Nobody knows what's happening to them, nobody can track them anymore," Mburanumwe says bleakly, eyes fixed on the verdant slopes of dormant Mikeno volcano, where about 190 of the world's remaining 700 mountain gorillas live.
"It's a catastrophe," he says, turning away from the mountain, its mighty peak rising through the mist. "For them and for us."
When Mburanumwe was a boy, he watched his father put on a uniform and boots every morning as the light of dawn crept into their home. His father was a ranger. He became one, too.
Rangers in eastern Congo take great risks to save animals in a part of the world already heavy with human suffering. The job doesn't come with a steady paycheque, but it offers the security that comes with cradling a weapon in a region where the most powerful people - soldiers and militiamen - are usually the best armed.
Another ranger, 46-year-old Diddy Mwanaki, joined the park service in 1991 after a friend tipped him off to a vacancy. It's the only job he's ever had.
After weeks of training, Mwanaki was given a camouflage uniform and a rifle and taught how to fire it. Soon he was deployed with a radio-equipped team of trackers, observing the massive, jet-black gorillas that he and other villagers back then thought of as "monsters."
"I was surprised to find they were just like man, except that they cannot speak - at least not like we do," Mwanaki says. "It's true they can be aggressive - but only when they are aggressed. This is not always true of man."
When war first broke out in 1996, he fled the park's southern gorilla sector along with dozens of other rangers. Mwanaki and Mburanumwe are used to gauging the intensity and nearness of volleys of gunfire while on patrols or tracking missions - and deciding when to flee.
Threats abound: Heavily armed poachers, charcoal traders, traffickers who kidnap young apes to sell them for thousands of dollars. The rangers, who sport army-style berets and sometimes bandoliers of bullets wrapped over their shoulders, have even set fire to thatch-roof homes erected illegally in the reserve.
The biggest threat are militias and rebels from Congo, Rwanda and Uganda. Some rangers have been abducted and forced to work as guides for armed groups unfamiliar with the terrain. Rwandan militiamen held ranger Anicet Baziheraho for three weeks last year until he escaped from their forest base. "They tied me up and beat me," he says, showing scars on his wrists from the ropes. "They said I was a spy."
Robert Muir, who has worked in the region for years for the Frankfurt Zoological Society, describes the rangers' work as "a struggle to survive."
"The park is literally awash with military and militia and rebels who may not understand that the rangers are there to protect and conserve the wildlife, who may mistake the rangers for another rebel group, or who may fully understand who and what the rangers are and see them as a threat," Muir says.
Some rangers have died in assaults where hundreds of fighters surround a park station and rake it with automatic weapons fire, even rocket launchers. Attackers often pillage everything they can from park stations, from VHF radios to computers. They have ripped off solar-panelled rooftops and carted away stocks of food, including live chickens.
Muir's group has expanded beyond wildlife consideration to supply emergency food, clothing, medicine and shelter to rangers.
In the past decade about 120 of the 660 rangers have been killed on the Congo side of the border alone, a tenth of them in the gorilla sector.
Meanwhile, the gorilla population in Central Africa's Virunga Conservation Area - a fertile volcanic mountain chain spanning the frontiers of Congo, Rwanda and Uganda - has risen by roughly 10 per cent over the same period to about 380 today. The world's other 320 mountain gorillas live farther north in Uganda's Bwindi Impenetrable Forest.
Villagers are perplexed by the rangers risking their lives to watch over the giant creatures which sometimes eat their corn stalks.
"People often ask us, 'Do you think gorillas are more important than man? Why do you protect them and not us?"' Mwanaki says. "I tell them it's in all our interests, because if we don't protect them, we'll have lost something forever - not just the gorillas, but a source of income."
Across the border in Rwanda, tourist cameras click nonstop at a family of 23 gorillas on the edge of a dense bamboo forest. Youngsters tumble on top of each other in the crisp morning air.
More than 12,000 tourists make such treks to Rwanda each year, paying $500 a piece for the privilege. Back in Congo, tourism operators can't even get insurance to bring groups in, Muir says.
Still, Mwanaki and other rangers managed to escort about 817 people on gorilla visits in 2007. Most were expatriate humanitarian workers - not tourists - living in the nearby provincial capital, Goma.
Beside the park's southern headquarters at Rumangabo, six crude wooden crosses rise from a hillside.
Most of the graves belong to a gorilla family named Rugendo, whose 12 members were cut to five in July in the worst single assault recorded to date. The dead included the group's leader, a grey-haired silverback named Senkwekwe who took charge of the family in 2001 when his own father was killed during clashes. The names are given to them by the rangers.
Mburanumwe learned of the massacre after a call on his cellphone from his father, who is still a ranger. The rangers cut down nearby trees, converted them into makeshift stretchers and carried the slain gorillas out of the park "up high, like kings," Mburanumwe says.
Conservationists suspect the assailants were linked to the lucrative charcoal trade, dependent on trees chopped down illegally. It is conducted so openly that even trucks overloaded with hundreds of sacks move easily through army roadblocks.
Today, the rangers' daily gorilla tracking expeditions have ground to a halt, with the front line of the war cutting straight through the Virunga reserve. But the rangers continue to blog about their lives on an Internet site hosted by WildlifeDirect, which helped draw in more than $260,000 of cash for equipment and salaries last year, according to the American charity.
These days, the blog is filled with reports of shelling and gunfire, and sometimes seems more like a war diary than a conservation log.
"We're not used to this," Mburanumwe says, sitting in a Goma house with other colleagues unable to enter the reserve, typing on a laptop fuelled by a humming generator outside.