Can We Save Africa's Great Apes?

It’s becoming the planet of the disappearing apes.

Africa’s great apes could lose between 85% and 94% of their range by 2050, a new study finds. The threats to their habitat include climate change, land use, and human disturbances. If those pressures continue, their range will continue to shrink and their chances of survival will also dwindle, researchers say.

With climate change, some of their lowland habits are becoming drier and warmer. And lowland vegetation is growing up to new places in the mountains. Animals that rely on those habitats have to shift their range in order to avoid extinction.

All African great apes are classified as endangered or critically endangered by the International Union for the Conservation of Nature (IUCN) Red List. Mountain gorillas, bonobos, Nigeria-Cameroon chimpanzees, eastern chimpanzees, and central chimpanzees are endangered. Grauer's gorillas, Cross River gorillas, western lowland gorillas, and western chimpanzees are critically endangered. They’re all considered flagship species for conservation, the researchers point out.

University of British Columbia conservation researcher Jacqueline Sunderland-Groves is part of the international team that studied how these threats have an impact on the survival of Africa’s apes. Their research was published in the journal Diversity and Distributions.

She talked to Treehugger about the research and what measures might be taken to help the survival of gorillas, chimpanzees, and other great apes.

Treehugger: What was the impetus for your research?

Jacqueline Sunderland-Groves: I spent a decade researching the Critically Endangered Cross River gorilla and the Endangered Nigeria-Cameroon chimpanzee which straddle the international border between Nigeria and Cameroon, to understand their density, distribution, and ecology. The Cross River gorilla is the most poorly known of all gorilla forms and has the smallest population size of any great ape with only 250-300 surviving in the wild today. Understanding their ecology; where they live and how they are surviving is critical to aid future conservation planning strategies. 

Together with other scientists and researchers across Africa, I contributed my great ape occurrence data to this important new study, which is the first to combine climate, land use, and human population changes to predict specific distributions of African apes by 2050. These results have serious implications for how we best plan to ensure the future survival of the charismatic great apes across their entire African range. 

What are the primary threats to the habitats of great apes?

In recent history, we have seen significant declines in all great ape populations and their natural habitat. As such, all great apes are listed as either Critically Endangered or Endangered by IUCN, and they continue to be marginalized and fragmented across their range by habitat loss and hunting.

Habitat loss is caused by the extraction of natural resources through commercial logging, mining, conversion of forests to make way for large-scale agricultural plantations or other human development activities like roads and infrastructure, all of which encroach on great ape habitat. As our activities exacerbate climate warming, many areas of lowland forest are expected to become uninhabitable by apes and other species, which has serious implications to the future survival of great apes. 

Why is it so critical that they don't lose their range?

Great apes rely on very specific habitats, largely pristine diverse forests, which provide all the food resources and space they require to survive. If those forests disappear, then ultimately so will the great apes. But these forests aren’t just important for great apes and other charismatic wildlife species. They are also critical for human health. Healthy forests equate to healthy animals and healthy people. None of us can afford to lose our natural forests.

What were the main findings of your research?

Combining climate, land-use, and human population data across present day great ape range, this study predicts that under the best-case scenario, we can expect a range decline of 85%, 50% of which is outside of protected areas. And worst-case we would see a range decline of 94%, of which 61% is outside of protected areas.

Potentially, and if great ape populations do shift their range in response to changing landscapes, we can expect some significant range gains, but there is no guarantee that they will. Apes may not be able to occupy these new areas immediately due to their limited dispersal capacity and migration lag. It takes a long time for a great ape population to change their range. 

Are these changes and losses unavoidable?

Most importantly, this study shows that we have time to mitigate these predictions. Some climate change-related range loss can be avoided if appropriate management measures are taken, and we take real strides to reach our climate goals. At the same time, if we increase the protected area network within great ape range states based on suitable habitats for them and ensure that we are utilizing eroded habitats for development rather than pristine dense rainforest, then we could mitigate much of the predicted loss.

What can conservationists learn from your findings? How can they be used to protect the animals' habitat?

New plans to conserve great apes need to be looking at the long-term and utilize the best science available to guide our efforts. This study demonstrates how we can plan for great apes, placing our efforts on minimizing habitat loss, and extending the current network of protected areas and corridors to maintain connectivity. We still have time to rewrite the future for great apes, now we just need to make this a reality.