Great ape habitat in Africa has dramatically declined
28th September 2012
The first continent-wide survey of African ape habitat shows a dramatic decline in recent years.
Over the last few decades, great ape numbers have plummeted across Africa – due to increasing rates of commercial hunting, environmental destruction, and disease. A continent-wide database of their habitats is now available at the A.P.E.S. portal.
The research combined over 15,000 field data points on chimpanzees, gorillas and bonobos. These results estimated the continent-wide distribution of suitable ape habitat conditions and changes over the past 20 years. Over 200,000 km² of ape habitat have been lost since 1995 – approximately four soccer fields every day.
This decline varied dramatically among species, however. Over 50% of eastern gorilla habitat has been rendered unsuitable, for instance, compared with about 10% or less for chimpanzees. This, the authors say, may be due to differences in ecological requirements, such as dietary preferences, as well as differences in vulnerability to hunting related to the behaviour and social structure of the different species.
The regions that experienced the greatest loss of suitable ape habitat were the Congo Basin rainforest and the West African coastal forest in Liberia. Importantly, the lack of decline in other areas may reflect the fact that much habitat had already been lost before the 1990s, such as in the East and West African regions. Even more concerning is the finding that suitable habitat loss appears to have been particularly severe in the central African forest block - currently regarded as the remaining stronghold of great apes. Even these vast and once-remote forest tracts have been interlaced with logging and mining roads and subsequent human immigration.
Inaoyom Imong, of the Wildlife Conservation Society in Nigeria and PhD student at the Primatology Department of the Max-Planck Institute for Evolutionary Anthropology (MPI-EVA): "This study shows how threats to African great apes are increasing over time throughout their range. It highlights the urgent need to intensify conservation measures, including law enforcement and raising awareness. Increased and sustained commitment of all stakeholders – local and international – to conservation efforts throughout the range of African great apes is essential to their survival."
"This is the first continent-wide estimate of African great ape distribution and its changes over time", says Jessica Junker, also a PhD student at MPI-EVA and lead author of the study. "This is also the first study to have combined data across 22 African ape range countries in an attempt to bridge the gap between local efforts in the field and global ape distribution patterns. We hope that together with a series of other geo-referenced data on human activities, land-cover, topography, and conservation, our model will aid funding agencies, industry and politicians in making decisions in identifying priority conservation areas, research gaps, potential wildlife corridors and future survey sites."
"Once again, a multi-site analysis has demonstrated the increasingly grave situation in which the African great apes exist," says Fiona Maisels of the Wildlife Conservation Society. "Threats to these species are rapidly increasing: bushmeat hunting continues to expand and the rate of habitat conversion from forest to oil palm plantations and other monocultures is about to explode."
Dr. Hjalmar Kuehl, another co-author: "The situation is very dramatic. Many of the ape populations we still find today will disappear in the near future."
Full details are published in the journal Diversity and Distributions.