As climate change and population growth deepen the human footprint on our planet, Earth's biodiversity is increasingly threatened (ScienceNOW, 2 July). For conservationists, insuring that other species have a fair chance to share the planet can sometimes seem like a losing battle. But three papers published by Science this week showcase conservation success stories that may point the way to future victories for endangered animals and plants.
The first piece of good news comes from Europe. In 1979, the European Union (E.U.) enacted a Birds Directive. It listed 181 endangered species and required E.U. countries to improve their habitats, for example, by creating special protection areas. A team led by biologist Paul Donald of the Royal Society for the Protection of Birds in Sandy, U.K., assessed how well the directive was working in the original 15 E.U. countries. The researchers used five different criteria, including whether populations of the listed birds had grown faster than those of species not on the list, and whether the listed birds did better in the E.U. than in other countries not bound by the directive.
When bird inventories from 1970 to 1990 were compared with those from 1990 to 2000, the answer was clear. For at least four out of the five criteria, the E.U.-listed birds did significantly better, the team reports. Moreover, Donald and his co-workers found strong evidence that the directive was responsible: There was a strong correlation between the percentage of its land each E.U. country set aside as protection areas and the overall success of the birds.
While Europe's birds were flying higher, the most endangered mammal in North America nearly crashed into extinction. The black-footed ferret once roamed over 11 Great Plains and Rocky Mountain states, as well as parts of Canada. But expanding croplands and extermination campaigns against the ferret's primary prey, the prairie dog, had dwindled its population to just 18 ferrets in Wyoming by the late 1980s.
A team led by mammalian biologist Martin Grenier of the Wyoming Game and Fish Department in Lander has found that the species is now recovering rapidly in Wyoming's Shirley Basin, thanks to a program of captive breeding and rerelease into the wild. Although early attempts to breed the animals failed when infectious diseases killed off a large number, leaving just five ferrets in the basin by 1997, the population had grown to 223 by 2006, the team reports. The secret of the animal's success, the researchers conclude, is that black-footed ferrets do most of their reproducing when they are about a year old, much younger than most other mammals do--thus fueling rapid population growth.
Finally, conservation policies seem to be paying off in the tropical rainforests of Peru. Whereas damage to Amazonian forests in neighboring Brazil from road building and encroaching developments has generated a lot of media coverage, the impact of human activities in Peru has received little study. A team led by ecologist Gregory Asner of the Carnegie Institution of Washington in Stanford, California, found that more than 600 square kilometers--or 0.1%--of the Peruvian Amazon were damaged or deforested each year between 1999 and 2005, owing to human activities such as the paving of the Interoceanic Highway. Nevertheless, only about 1% to 2% of this damage took place within designated protected areas, and only 11% of the deforestation occurred in areas occupied by indigenous communities, the researchers report. The Science papers provide "groundbreaking evidence" that conservation strategies work, says Thomas Brooks, a conservation biologist at Conservation International in Arlington, Virginia. Nevertheless, he and others caution that the battle is far from won. For example, Samantha Wisely, a wildlife biologist at Kansas State University in Manhattan, notes that although the renaissance of the black-footed ferret "offers inspiration and confirmation that endangered species can be recovered," other government actions--such as the U.S. Forest Service's plans to poison prairie dogs in a second ferret-reintroduction area in South Dakota at the request of some cattle ranchers--threaten their survival.