The population of the endangered West African chimpanzees in Ivory Coast has fallen by about 90% in less than 20 years, a study has suggested. Researchers found 90% fewer nests than a similar audit carried out in 1990, which suggested the chimp population had crashed from 12,000 to about 1,200. Increased levels of deforestation and poaching were likely to be main factors for the decline, they added.
Details of the survey’s findings appear in the journal Current Biology. Ivory Coast, thought to be one of the last strongholds for the species (Pan troglodytes verus), was believed to be home to between 8,000 and 12,000 individuals. This estimate was primarily based on a nationwide survey carried out in 1989 and 1990.
When scientists carried out the most recent count in 2007, using the same techniques as the 1990 audit, they discovered a very different situation. The researchers revisited 11 sites that had been surveyed 17 years earlier.
Professor Christophe Boesch, a director at the Max Planck Institute for Evolutionary Anthropology, Germany, said poaching and deforestation were on the increase as a result of the nation’s rapidly growing human population. The number of people living in Ivory Coast is now estimated to be 18m, up from 12m in 1990.
“The forest has been cut back in order to grow cash crops and other things,” he explained. “Also, chimpanzees, like many other species, are hunted for their meat. In some regions, including West Africa, something called ‘empty forest syndrome’ has been recorded. “This is where the forest itself is still intact but it has been emptied by hunting.”
But Professor Boesch said that there was one glimmer of hope in the otherwise bleak findings. One of the sites was located within the boundaries of Tai National Park, where the local population of chimps had fared much better. “Our closest living relative will not survive, and I ask myself about what this means for the future of humans if we let this species disappear.”
- from bbc
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