A band of park guards defending a population of rare eastern lowland gorillas against rebel armies and poachers in the Democratic Republic of Congo, has made it possible for the endangered animals to survive - and even to increase their numbers.

Scientists with the Bronx Zoo-based Wildlife Conservation Society (WCS) have just completed a census showing that there are more gorillas today than there were five years ago, although the population is still small.

The census, led by WCS project director Innocent Liengola, counted 168 gorillas living in the mountain highlands of Kahuzi-Biega National Park. Conservationists are encouraged by his discovery that some of the gorilla family groups had infants.

A male eastern lowland gorilla in Kahuzi-Biega National Park (Photo courtesy WCS)

The ability of the park guards to negotiate with rebels and potential poachers has kept the gorillas safer than expected, WCS said.

Eastern lowland gorillas, also called Grauer's gorillas, are the tallest of the ape species. They live only in Congo and inhabit a forested area from Lake Albert near the Ugandan border to the northern tip of Lake Tanganyika on the frontier with Burundi.

The tropical forest park is dominated by two spectacular extinct volcanoes, Kahuzi and Biega. Founded in 1970 and declared a UNESCO World Heritage Site 10 years later, Kahuzi-Biega National Park was supposed to be a sanctuary for the endangered apes.

But ongoing insecurity in the region has made Kahuzi-Biega extremely dangerous for conservation work. As recently as last May, Liengola and his colleagues attempting to count gorillas had to flee the area in the face of automatic weapons-fire exchanged between two rival militias.

A census under difficult conditions in 2000 estimated 120 to 130 gorillas in the same area. Preliminary surveys from other regions in the park and outlying areas have also shown these rare large primates to continue to persist, despite some recent reports that the animals are nearing extinction.

"The fact that this Grauer’s gorilla population may actually be increasing is a tribute to the park guards who have stood their ground against rebel armies and poachers. They are true conservation heroes," said WCS Conservationist Dr. Jefferson Hall, who conducted the first Grauer’s gorilla census in 1996.

"I’m absolutely convinced that if the guards did not remain in Kahuzi Biega, there would be no animals left," he said.

Eastern lowland gorillas survive against all odds. (Photo courtesy WCS)

Following his survey, the population was hit by the onset of Congo’s long civil war, which has raged across much of the country.

"When we counted up the numbers of gorillas we knew had been killed during the war, we thought we might find fewer than 100 left," Liengola said about the current census.

"The survey results show us that even sensitive species like gorillas can make a comeback if they are protected and their habitat remains intact, he said. "The challenge is to hold this trend."

Five years ago a survey team of 10 was killed by rebel fighters during attempts to demarcate the park border.

In 1997 UNESCO inscribed the park on its List of World Heritage in Danger. "The site has been much affected by the influx of refugees," UNESCO wrote at the time. "Park facilities had been looted and destroyed, and most of the park staff have fled the area. The park may also be serving as a hideout for large militia groups, as well as for illegal settlers. This has led to fires, increased poaching and the illegal removal and burning of timber."

The eastern lowland gorilla is the least-studied of the four gorilla sub-species. More than three-quarters of the world’s population is believed to be living in and around Kahuzi Biega National Park, though WCS says a total population estimate remains unknown.

The WCS program in Kahuzi-Biega is supported by Deutsche Gesellschaft für Technische Zusammenarbeit (GTZ) of Germany, the Born Free Foundation, the Hallewell Foundation, USAID, the U.S. Fish and Wildlife Service, and UNESCO.