Researchers found that tropical mammals living within protected areas are not immune to the effects of human activity, even when it occurs outside of the protected boundaries.

The study, published in Nature Ecology and Evolution, could help 30 by 30 participants make biodiversity policy decisions. Based on the largest long-term camera-trap wildlife survey of its kind to date, the study sheds light on how anthropogenic stressors like human population density and habitat fragmentation affect 159 mammal species across three biogeographic regions in 16 protected areas.

The data set was assembled by a large-scale network of research stations that agreed to implement a consistent data-collection protocol as part of a partnership between Conservation International, the Wildlife Conservation Society, and the Smithsonian Institution. It is made up of millions of images collected over multiple years from over 1,000 camera-trap sites.

“This data set is just phenomenal — it was a herculean effort unlike anything attempted before,” said Beaudrot, an assistant professor of biosciences.
The study found that specialist species — which occupy specific habitats only — thrive when habitat fragmentation is low and are generally more susceptible to the negative impacts of human activities like hunting and land use than generalist species, which are able to live in more diverse habitats.

Thus, a white-bellied pangolin living in the Bwindi Impenetrable National Park in Uganda should shuffle closer to its centre, since specialists are likely to fare better the farther inward they are from the edge of a protected area.
“Habitats are more varied at the edge of the protected area,” said Asuncion Semper-Pascual, a postdoctoral researcher at the Norwegian University for Life Sciences and the lead author of the study.

“There is usually this difference between forest cover and open landscape, such as an area used for agriculture, etc. Some generalist species thrive in this diverse setting because it provides access to different resources.”

Generalist species, such as the tayra — a dog-sized omnivore in the weasel family that is at home both under forest cover and in grasslands or cropland, only thrive near the edge of protected areas if human population density there is low.

Understanding species-specific responses to different anthropogenic stressors can help set conservation priorities and guide protected-area management — locally by focusing on the most vulnerable species in a region and globally by highlighting how landscape-scale factors impact biodiversity beyond the protected perimeter.

“We have to think about the situation holistically,” Beaudrot said. “Conservation is going to work best when it’s tackled in specific contexts and in concert with the people who live there so as to create win-win situations for both the people and the wildlife.”
“As more protected areas are created, we need to think carefully about the factors both within and outside protected areas that influence biodiversity,” Semper-Pascual said.