Tropical forest reserves are failing to preserve biodiversity, often because of poor management.
A team of more than 200 scientists has conducted hundreds of interviews with experts on 60 protected areas in 36 countries and found that four-fifths had experienced some declines in health. About half of the areas had suffered more serious losses to biodiversity.
"If you put a boundary around a piece of land and install some bored park guards and that's all you do, the park will eventually die," says University of Pennsylvania biologist Daniel Janzen. "It's death from a thousand cuts."
Among the types of wildlife and plants most negatively affected were bats, amphibians, lizards, large-bodied mammals, stream-dwelling fish, amphibians and old-growth trees. And this may be the tip of the iceberg, as the researchers didn't even attempt to monitor insects, fungi or other small organisms.
Much of the reason appears to be us. Environmental conditions and activities occurring outside of the reserves strongly predicted the biodiversity within. Logging, declining forest cover and increasing fires outside the protected areas tended to pull down the health of the reserves themselves.
The biggest problem is often getting the political and economic support to stave off threats from human activity in protected areas. And conservationists can't take a cookie-cutter approach to designing and managing protected areas, says Janzen.
"You have to fine-tune and tailor-make your park to the particular circumstances of a place: the nature of the people, the resources and the organisms," he says.