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10-year plan hopes to give western chimpanzees a fighting chance

Without immediate action, the plan’s authors say they fear the western chimpanzee subspecies will soon become extinct. Image courtesy of Liran Samuni/Tai Chimpanzee Project.

  • The IUCN recently released its latest 10-year action plan for the critically endangered western chimpanzee.
  • Poaching, habitat loss and disease were identified as the key threats to the species.
  • These threats were found to be exacerbated by the high rate of population growth in West Africa, resulting in rapid agricultural expansion and a demand for economic development projects.
  • The IUCN plan sets out nine strategies to be implemented between 2020 and 2030; they include filling research gaps, ensuring chimpanzees are considered in land use planning, improving legal protection, and raising awareness of the plight of western chimpanzees.

Western chimpanzees are the most threatened of the four confirmed chimpanzee subspecies. Conservationists estimate that populations of the western chimpanzee (Pan troglodytes versus) declined by 80% between 1990 and 2014. Large tracts of chimpanzee habitat have already been lost, and much of what remains is in the crosshairs of agriculture, industry and infrastructure development.

Adding to the pressure, in their West African home, the subspecies shares its space with the world’s fastest-growing human population. Without immediate action, the IUCN warns the western chimpanzee may soon become extinct.

The IUCN recently released its latest 10-year action plan, setting out nine key strategies to protect chimpanzees. On the agenda are improved legal protection, raising awareness, and more research into their distribution, genetics and behavior. The plan also highlights the need for chimpanzees to be considered at all levels of the land use planning process if they are to have a future in the rapidly developing West Africa region.

“The western chimpanzee is in dire need of coordinated and effective conservation action right now,” said Erin Wessling, a postdoctoral fellow at Harvard’s Department of Human and Evolutionary Biology and lead editor of the IUCN plan.

The western chimpanzee’s range extends across eight countries in West Africa: Côte d’Ivoire, Ghana, Guinea, Guinea-Bissau, Liberia, Mali, Senegal and Sierre Leone. The subspecies is already locally extinct in Benin, Burkino Faso and Togo.

The western chimpanzee is the most threatened of the four known chimpanzee subspecies. Image courtesy of Liran Samuni/Tai Chimpanzee Project.

Fighting for space

The exact challenges western chimpanzees face vary by location, but the IUCN has identified common key threats across the region: poaching, habitat loss, and disease.

According to U.N. population data, almost half of West Africa’s 367 million inhabitants were 15 or younger in 2015, making it highly likely that the region’s current rapid population growth will continue in the near future. Agricultural production in West Africa has been growing even faster than population growth in the last 30 years, allowing the region to greatly reduce undernourishment.

While vital for West Africa’s food security, this rapid agricultural expansion has had unfortunate consequences for chimpanzees. Much of their habitat has been lost to subsistence and industrial agriculture, and what remains has become increasingly fragmented.

In Côte d’Ivoire, once home to one of the largest populations of western chimpanzees, widespread agricultural expansion for coffee, cacao and palm oil has seen the chimpanzees’ range cut by 70%. Researchers now believe that only small remnant populations of a few hundred individuals remain in two of Côte d’Ivoire’s national parks.

Large portions of the remaining chimpanzee habitat in West Africa — as much as 80% in Liberia — are also suitable for oil palm production,  a valuable export crop. Without a voice for chimpanzees in the land use planning process, experts fear the lure of foreign exchange may well override any conservation concerns.

Living alongside chimpanzees can pose a disease risk for both chimpanzees and humans. The IUCN calls for disease monitoring and disease risk analysis in its new plan. Image courtesy of Erin Wessling.

As well as agriculture, artisanal and industrial mining, logging, new roads and development projects all have an impact on chimpanzee habitat. According to a study modeling western chimpanzee distribution, 10% of chimpanzees live within 25 kilometers (16 miles) of four major development corridors planned in West Africa.

“As large-scale land-use change is occurring across West Africa, this action plan points out the need for integrated land-use planning that involves chimpanzee experts,” said Stefanie Heinicke, a postdoctoral researcher with the Potsdam Institute for Climate Impact Research and one of the authors of the IUCN plan.

At present, chimpanzees are sometimes considered in environmental impact assessments for individual projects in the region. However, the IUCN plan argues that unless the cumulative impact of multiple projects is considered, the full impact of development on chimpanzees can’t be seen.

Chimpanzee experts need to have a voice in the planning practice, argues the action plan, which was developed following a four-day workshop in Monrovia that included representatives from the governments of all eight range countries as well as NGOs and researchers.

The authors propose that environmental assessments be carried out at both a national and range-wide level to assess the impact of development and land use change on chimpanzee populations and identify important no-go zones to protect. The IUCN plan also emphasizes the importance of ensuring land use planners have accurate information on the likely impact of developments on chimpanzee populations. As a last resort, the IUCN suggests establishing “offset” programs to counteract the impact of development projects on chimpanzees.

An artisanal gold mine in Senegal. Due to their informal nature, artisanal mines aren’t normally considered in formal land use planning, but they still have an impact on chimpanzees. The IUCN plan calls for artisanal mining to be covered by land use planning processes to protect chimpanzees. Image courtesy of Erin Wessling.

Danger from all sides

In addition to fragmenting habitat, infrastructure projects like roads also make chimpanzee habitat more accessible to poachers — 60% of western chimpanzees already live within 5 km (3 mi) of a road. Bushmeat consumption is the main driver of direct killing of chimpanzees in West Africa, with researchers documenting the availability of chimpanzee meat in both rural and urban bushmeat markets. Chimps are also killed for their body parts and as a result of human wildlife conflict, or are captured live for the exotic pet trade.

Heinicke’s modeling study calculated that 83% of the estimated 52,800 remaining western chimpanzees live outside protected areas, leaving them especially vulnerable.

“As less than 20% of western chimpanzees occur in high-level protected areas, the strengthening and extension of protected areas is a central strategy of this new conservation action plan,” she said.

And even living in a protected area is not a guarantee of safety. A study surveying hunters around Liberia’s Sapo National Park recorded 74 chimpanzees killed and eight infants captured alive in two months.

To tackle this, the action plan calls for increased legal protection for chimpanzees and international coordination to improve the enforcement of wildlife laws.

“Laws and protected areas dedicated to protecting this subspecies haven’t been as effective as we need them to be,” Wessling said. “To do so will require that chimpanzee conservationists have a seat at the table in the discussions.”

There are also other consequences to the growing proximity between chimpanzees and humans.

“An increasing spatial overlap can increase the risk of disease transmission between humans and chimpanzees, and can also increase the likelihood of conflicts,” Heinicke said.

Without immediate action, the plan’s authors say they fear the western chimpanzee subspecies will soon become extinct. Image courtesy of Liran Samuni/Tai Chimpanzee Project.

With many physiological similarities, chimpanzees are susceptible to a number of human diseases, and vice versa. Chimpanzees are known to have caught human respiratory diseases, including a type of human coronavirus, that can prove fatal. Another disease of major concern in the West Africa region is Ebola. While there is no evidence that chimpanzees have been affected in the worst outbreak, from 2014-16, gorilla and chimpanzee populations have been severely affected in the past.

The action plan calls for disease monitoring and risk analysis to understand and mitigate the risks of disease transmission between humans and chimpanzees, an issue that has recently shot to prominence in light of the current COVID-19 pandemic.

Another area the plan focuses on is the need to fill gaps in scientific knowledge about the distribution, behavior and genetic diversity of western chimpanzees — an area also highlighted in the previous action plan.

“Since the last conservation action plan … many areas across West Africa have been surveyed,” Heinicke said. “However, there are still gaps, especially in terms of chimpanzee density and distribution.”

The remaining strategies in the action plan call for an increased awareness of the plight of western chimpanzees at both the local and international level, and the need for effective long-term financing for chimpanzee conservation.

With rising competition for chimpanzee habitat and increasing proximity to West Africa’s growing human population, the future for the western chimpanzee is precarious. Wessling and Heinicke say they are hopeful that the nine strategies the IUCN plan sets out can offer a glimmer of hope for the western chimpanzees.

“There’s an urgent need to make calculated efforts to give this subspecies a chance,” Wessling said. “[T]he consequences if we aren’t effective are immense.”

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