In an 85-square-kilometer swath of rainforest in Côte d'Ivoire's Taï National Park, monkeys call to one another, chimps drum on tree trunks, and tiny antelopes rustle through the underbrush. That's where researchers have been studying primate communities for more than 3 decades. Step outside the research zone, though, and the animal sounds fall silent. The forest is noticeably emptier as a result of heavy poaching. Field researchers all over the world have noticed that long-term research sites double as sanctuaries, but they've never had the numbers to prove it. Now they do.
In 1979, scientists from the Max Planck Institute for Evolutionary Anthropology in Leipzig, Germany, established a research site within Taï National Park to study chimpanzees, and a decade later another group began studying monkeys nearby. Back then, the entire park was teeming with animals, says Geneviève Campbell, a graduate student in primatology at Max Planck, but illegal hunting has since been on the rise. As in many parts of Africa, there are few rangers and little money for extensive patrols, and poachers operate with impunity throughout much of the park, Campbell says. Studies have shown that tourist traffic deters poachers, who may steer clear of other people in part to avoid getting caught. But nothing of the sort had been documented for researchers.
For the present study, published online today in Biology Letters, Campbell and several colleagues established 75-kilometer-long study transects, or temporary flagged paths. They spaced the transects evenly throughout a 200-square-kilometer area that encompassed most of the long-term research area, where the chimpanzee and monkey projects are located, and adjacent park forest. The researchers walked each transect three times during an 11-month period, tallying the primates and duikers—small antelopes—that poachers target, as well as evidence of their presence, such as chimp nests and duiker dung. They also recorded signs of poaching, such as campsites, traps, and empty gun cartridges.
They fed the numbers into a computer model to test whether distance from the research area, density of people, forest type, or distance to the park border best predicted the presence of animals and signs of poaching. Sure enough, distance from the research area was the only consistent and significant predictor. There were at least six times more animals near and within the research area than farther outside. The researchers found almost no signs of poaching within and around most of the area and up to 15 times as many signs outside it.
"Now people can at least say with certainty that their presence [has] a positive effect," Campbell says. She hopes the study will provide researchers with ammunition when they seek funding for long-term work in heavily poached areas. These have become a grim reality in many places, and even researchers more interested in behavior than conservation are realizing that they need to get involved. "All the primate populations are threatened," Campbell says. Even for researchers who are not conservation-minded, she says, "if their study animals are dying, they cannot continue their research."
Joshua Linder, a biological anthropologist with James Madison University in Harrisonburg, Virginia, says he's noticed the protective effect of long-term research sites in Cameroon, where he studies primates and the bushmeat trade. Linder says he appreciates the confirmation provided by the paper and has no doubt that it will be cited in many grant applications and papers. But whether it will burst open the funding gates is another question. "It's really, really hard to get long-term funding," Linder says. "I don't know if that's all of a sudden going to change because of this article."
Fabian Leendertz, a wildlife veterinarian with the Robert Koch Institute in Berlin, runs the veterinary program for the Taï chimpanzee research project and has worked with the monkey project. In a 2008 paper, he and colleagues documented the transmission of viral respiratory disease from people to chimpanzees living in the Taï research area, highlighting research's possible negative consequences. But the bigger picture was abundantly clear even then, he says. "There are way more animals in the research area than around [it]," Leendertz says, and when it comes to long-term research projects, "the benefit is, I think, always bigger than the possible harm."