Not since George Schaller trekked through the remote jungles of Belgian Congo nearly 40 years ago have scientists known how many Grauer's gorillas lived in central Africa. Now, a seven-year census recently completed by the Bronx-Zoo based Wildlife Conservation Society (WCS), and published in the current issue of the journal Oryx, reveals that the population of these mysterious primates has remained surprisingly stable despite growing human pressures. Conservationists warn, however, that local populations have become increasingly threatened due to political instability, hunting and deforestation.
The research team, led by biologists from WCS and the Institut Congolais pour la Conservation de la Nature (ICCN), estimated a population of 16,900 individual animals ‹ many more than expected since preliminary surveys showed a dramatic upswing of poaching outside of protected areas. In 1960, Schaller put the total at 5,000-15,000.
"Much to our surprise we found many more gorillas than expected," said Jefferson Hall who led the survey team for WCS, "Given the virtual collapse of the economy, the need for local people to rely on bushmeat, and general state of anarchy that has persisted for the last several years, we expected to find that many populations to be wiped out. While this has happened in areas adjacent to large centers of human population, the situation was not nearly as bad within parks and remote areas,."
By using a combination of methods including line transects to count nests and forest reconnaissance, researchers identified 11 separate populations living in four general regions in eastern Democratic Republic of Congo (formally Zaire). Two thirds of the total population inhabit Kahuzi-Biega, Maiko and Virunga National Parks. Outside of protected areas, the group found that poaching and habitat loss gravely threatened gorilla numbers. Several local populations documented by Schaller had vanished.
Hall and others argue that continued support for the Congolese park service is essential during these troubled times.
"Our data show parks have made a difference. Even in a war-torn country with a very bad economy there is hope for conservation. But no Grauer's gorilla population should be considered safe from extirpation," Hall said.
Even within protected areas, the team found evidence of poaching. In Kahuzi-Biega National Park, for example, at least one individual in each of the tourist habituated groups had lost a hand to snares. According to the study, recent reconnaissance indicates that many gorillas were killed immediately following the recent civil war.
ICCN scientist, Omari Ilambu, supported by WCS, has worked in the Kahuzi-Biega since last October to assess how the war has affected gorilla and elephant populations. So far, he has found evidence of heavy poaching of both animals.
Grauer's gorillas Gorilla gorilla graueri, also known as eastern lowland gorillas, are the least studied of the three gorilla sub-species, probably due to their inaccessible habitat, and most recently, political turmoil that has made in-depth research too dangerous. WCS is the only conservation organization studying all three gorilla sub-species.
Journal
Oryx