Hunting may be altering the social ecology of our closest living relative, the pygmy chimpanzee, or bonobo, making this endangered ape even more difficult to study and protect.
A new survey of the Lomako forest, a 3600-square-kilometre region of the Democratic Republic of the Congo (DRC), found more bonobos than expected, says Jef Dupain of the African Wildlife Foundation in Kanshasa (DRC), who carried out the study. But because their distribution was a lot patchier than has been seen previously, there were fewer actual nest sites, so the bonobos were more difficult to find.
This patchiness could be due to a natural social ecology not seen before, says Dupain. But the pressure of hunting is a more likely cause. Either way, protecting the great apes will be made even more difficult.
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The findings could go some way to explaining why other surveys have found so few bonobos. In 2002, Dupain carried out a similar survey of the Lomako Forest and found just a quarter of the population compared with previous studies. Then last December WWF jointly published the largest population survey of bonobos ever undertaken, this time covering the Salonga National Park, the only place where the bonobos鈥� habitat is protected. There they found so few apes that it was impossible to work out how many were left (快猫短视频 print edition, 11 December 2004).
In the new study Dupain and colleagues covered about 100 square kilometres of the Lomako. By looking for evidence of the apes, such as nests or actual sightings, they calculated that the population density was roughly equivalent to pre-2002 levels 鈥� about two individuals per square kilometre.
Hunting and poaching
There is still clear evidence of poaching, says Dupain, but the situation is not as bleak as it seemed just months ago. 鈥淲hat鈥檚 becoming clear from these studies is that we still have lots to learn about their distribution and abundance,鈥� says Peter Stephenson of WWF鈥檚 African Great Apes Programme.
What we do know is that hunting is rife in all the areas where bonobos live, says Annette Lanjouw of the UN Environment Programme鈥檚 Great Apes Survival Project. And if that is forcing bonobos to move around, it could have a very negative effect on their population structure and social ecology. 鈥淚t鈥檚 not just that their numbers are being decimated,鈥� she says. But also that they are being forced to move from their permanent settlements.
It is a very difficult situation, says Dupain. Just by studying the bonobos researchers can unintentionally lead hunters to the apes because of the trails they create. 鈥淭his is a huge problem,鈥� says Lanjouw. Both logging roads and research trails open up areas of the forest, making it easier for hunters to reach their prey, she says. 鈥淚t鈥檚 an invitation to hunters,鈥� says Dupain. 鈥淗owever, if we hadn鈥檛 have been there they would be hunted anyway.鈥�
