Where they rebuild nature

Humanity's footprint has grown so large that, increasingly, conservation means restoration of degraded landscapes and the reintroduction of species. Six case-studies with varying degrees of success show some hurdles and idiosyncrasies facing efforts to rebuild nature.

Conservation-minded leadership:

Costa Rica hosts 5 percent of the world's plant and animal species, more than Canada and the US combined. The government has worked for decades to conserve its natural heritage. One-quarter of its land is protected. And this pays off: Two million tourists visited in 2008, spending $2.2 billion – double what banana and coffee exports bring in. While deforestation remains a threat – and one species, Monteverde's Golden Toad, has disappeared – scientists cite the country as an example of what conservation-minded leadership can achieve.

The Philippine archipelago is what scientists call a biodiversity hot spot, hosting 1,100 land-dwelling vertebrates, half of which exist only there. But deforestation and poaching endanger one-fifth of vertebrate species and two-thirds of plant species. Some scientists take heart in a surge of home-grown conservation efforts that are credited with taking the lead in bringing the endangered Philippine cockatoo and the Visayan wrangled hornbill back from the brink of extinction in the past decade. New efforts are focusing on the Philippine crocodile.

Sometimes people prefer not to restore nature:

Sea otters were wiped out in British Columbia by the 1920s. Scientists reintroduced a few to Vancouver Island 40 years ago – and the population has grown to 3,000. But some indigenous communities aren't happy. Otters eat urchins and abalone, lucrative shellfish important to the local livelihood. With fewer grazing urchins, kelp forests have rebounded.

History may not be repeatable:

Florida's Everglades is one of the largest ecosystem-restoration projects. One goal of the $10.9 billion project: to reestablish the water flow from Lake Okeechobee. But the swamp is home to so many invasive species – pythons, wild pigs, jungle vines – that some people wonder if ecosystems are so altered that returning them to an historic state is possible. In such cases, what does restoration mean?

Conservation happens in spite of human conflict:

Only 700 mountain gorillas remain in the world – 380 live in the thick vegetation of the Virunga Volcanoes Conservation area, shared among Congo, Rwanda, and Uganda. Armed rebel groups in the war-torn region also inhabit the forest, slaughtering gorillas and other critters. Despite this, the gorilla population in the preserve has increased by 14 percent since the latest conflict began in 1998. How? Some credit goes to the intrepid park rangers. More than 100 rangers have been killed in violence over the past decade.

Using the market to save nature:

Madagascar, home to lemurs, baobab trees, and other unique species, is greatly degraded. Traditionally, Malagasies have practiced slash-and-burn agriculture. Deforestation and erosion are so severe that from space the island appears to bleed red into the surrounding ocean. But scientists are newly hopeful: Conservationists are tapping into emerging carbon markets for badly needed funds. They're selling off intact forest as carbon offsets. Dell bought a 900-square-mile swath of forest in Madagascar and turned it over to Conservation International for management.