Photo courtesy of Global Citizen/flickr.

BOGOR, Indonesia (1 February, 2012)_ Planting a thick hedge of repellent plants – such as hot chilli peppers – around farms can help African forest communities keep out primates who often raid crops to survive amid widespread deforestation and loss of habitat.

“Chilli peppers are non-palatable to apes and have, in some cases, proved a successful deterrent to invading primates,” Tatyana Humle, primatologist and lecturer at the University of Kent, said at a recent workshop held at the campus of the Center for International Forestry Research (CIFOR).

One of the main challenges facing primate conservation is the rising level of interaction between humans and great apes. “Humans and great apes basically are forced into conflict situations as land use changes to accommodate ever growing human populations and plantation expansions shrink existing forests to mere fragments,” said Terry Sunderland, a senior scientist at CIFOR.

According to the World Wildlife Fund, human-wildlife conflict is one of the main threats to the continued survival of many species, with elephants being the biggest crop raiding culprits. However there are also severe economic impacts on local people, many of whom are subsistence farmers, due to destruction of crops (a recent review by the FAO found that Indian farmers in Rajathstan lost 22% of their annual income due to crop losses from antelope invasion).

Compounding this issue is that in many areas of Africa, great apes, especially chimpanzees, occur outside protected areas and have become less fearful of humans. They are therefore more likely to raid crops, approach human habitation or even potentially attack humans if provoked.

IUCN guidelines on human and great ape conflict compiled by Humle and colleagues highlight that due to slash and burn practices, agricultural fields are often located adjacent to the borders of protected forest areas and forest edges and are therefore vulnerable to crop raiding by primates.

Greater distance from the forest reduces the susceptibility of farms or plantations to primate invasion, but this can also be effectively achieved by establishing buffer zones – blocks of land intended to discourage wildlife entrance –in the form of impenetrable barriers such as thorny bushes, or the use of unpalatable crops such as chilli peppers, chilli infused rope, or tea.

“Tea plantations, if wide enough, appear to provide effective barriers that mountain gorillas and other animals do not cross,” said Humle.

Western chimpanzee young male ‘Jeje’ aged 13 years stealing pineapples from villagers fields. Photo courtesy of Anup Shah.

Where great ape populations occur in fragments, the establishment and preservation of forest corridors that include a buffer zone, especially along riparian areas, may also reduce conflict in promoting greater availability and access to natural foods for the apes, while also helping link core habitats and preserve water sources.

These approaches however, are not without their challenges, with issues such as land tenure and financial sustainability due to requirements for buffer zone maintenance and management often arising.

“There is also some concern that the allocation of prime farming land for non-utilitarian buffering plants may impact local livelihoods i.e. the farmers are giving up valuable land to plants which may hold no economic gain to them. However, the resulting alleviation in crop losses due the presence of the buffer may outweigh such costs. A multi-buffer zone approach is also being encouraged, with farmers additionally planting “useful” subsistence and cash crops such tea that are non-palatable to apes.

According to Humle, animals – especially those as intelligent as great apes- may habituate to ranging in buffer areas containing chillies, reducing their effect as a deterrent.

“Solutions designed by humans are constantly challenged by adaptable wildlife. Once a human-wildlife conflict strategy has been designed and implemented, it needs to be properly monitored and constantly reassessed and revised otherwise it is not worth the investment.”

Africa’s experience in conflict management with buffer zones could yield many important lessons for Asia, said Humle. “The multi-buffer approach appears more promising since it provides an economic gain to local communities.”

However, constraints unique to Asia may limit the effectiveness of buffer zones. Agroforestry schemes often encourage farmers to grow fruit trees, which could exacerbate the problem of crop-raiding, said Humle. Compared to Africa, Asia also has a higher human population density, more fragmented primate populations outside protected areas, and a larger expansion of commercial activities that impact natural habitats – for example oil palm plantations.

“In situations of wildlife-human conflict, all stakeholders including villagers, local and national authorities, NGOs and relevant institutions etc., should be consulted in the design and implementation of mitigation schemes with expert advice. The greatest challenge is to strike a fitting balance between the needs of humans and great apes.” Humle said.

The workshop was the second of a series on “Great Apes and Poverty Linkages”, organized under the auspices of the Poverty and Conservation Learning Group (PCLG), and the International Institute for Environment and Development (IIED), with financial support from the United States Agency for International Development (USAID), United States Fish and Wildlife (USFW), the Arcus Foundation and the Great Apes Survival Partnership (GRASP). The event was hosted by CIFOR and the Forestry Research and Development Agency (FORDA) of Indonesia’s Ministry of Forestry.

Visit the workshop’s page to watch videos of presentations from the experts, read related blog stories and see pictures from the event and field trip to Central Kalimantan, Indonesia.