IN MAY AND JUNE 2004, scientists from the Nature Conservancy ran a Rapid Ecological Assessment of the Solomon Islands. For 35 days, they cruised 2,000 miles down the 950-island archipelago in their liveaboard dive ship, counting spinner dolphins and clownfish, Maori wrasses and beaked whales. The place was an astonishing hot spot of bio­diversity, teeming with 494 coral species and at least 1,019 species of reef fish, including several previously unknown to science.

The scientists also found significant evidence of overfishing, confirmation that these waters needed protection—and fast. But what they did next reflects an ongoing shift in conservation philosophy. Instead of just setting up a marine park to keep local fishermen out, the Nature Conservancy and its partners engaged the islands' tribal leaders, allowing them to manage the fishery for their own long-term economic interests. The conservationists scrapped pristine nature as the goal and put people first; the people, in turn, found a way to both create a protected area and keep fishing. Sea turtle numbers have almost tripled. And livelihoods have doubled.

"Too much conservation is about sequestering nature," TNC's chief scientist, Peter Kareiva, says. Environmentalists have always worked with local people, he points out; that's not new. "The difference is that now we're being more explicit about it. Instead of collecting data to see how the birds and trees are doing, we do household surveys to see, if we set up a marine protected area, whether the people in those communities feel better off. That's a down-to-earth, concrete change."

People? Really? Since John Muir first walked the Sierra, hasn't the point of conservation been to protect nature from people?

Not anymore. In a slow but dramatic shift, the world's biggest environmental NGOs—the Nature Conservancy, the World Wildlife Fund, and Conservation International—have retooled their goals. Saving chunks of nature by fencing people out is too piecemeal, too arrogant, they've come to believe. What's more, it doesn't work on the scale we need.

"The historic approach will fail," says Peter Seligmann, Conservation International's co-founder and CEO. If we don't rethink our tactics, he believes, "we will have islands in a sea of development, and islands are always eventually eroded."

That's a strong statement coming from Mr. Biodiversity himself. CI invented the term "hot spots"; since its founding, in 1987, when Seligmann and others peeled off from the Nature Conservancy, the group has championed the preservation of wild places above all else. But over the past two years, CI has embarked on a painful journey of consultant-aided soul searching. This fall, it announced a new mission: "to empower societies to responsibly and sustainably care for nature for the well-being of humanity."

In some ways, CI can afford this kind of drama; it's the only big conservation NGO not beholden to public members. But the turnaround required some harsh reexamination of its past successes. "With our conservation partners, we've put some 500 million acres of priority lands and waters in protected status," Seligmann told me. "That's an area about 30 miles wide that wraps around the equator. It seems really big—until you go to outer space and you look at the earth and you see it's actually a tiny bit of land. You look at the issues of climate change, consumption, and the state of the world's oceans and you realize that, although we've succeeded in putting a lot of land and waters into what I like to refer to as ‘the conservation pantry,' we haven't changed the hunger of development, nor have we reduced the capacity of development to reach into that pantry whenever they want something and pull it out."

Biodiversity is still crucially important to CI, he says, "but it has now become the indicator of the health of the ecosystem we're focusing on, as opposed to the driver of where we're going to work."

On the face of it, using biodiversity—the glorious variety of nature in all its forms—in the service of human well-being sounds pretty cynical. Tough times, snail darter! Nice knowin' you, polar bear! For those of us raised on the American idea of wilderness—on the sacred mission of keeping some places immune from being paved, bulldozed, and mined—scrapping that notion rips at the foundation of our beliefs. When I brought this up with Kareiva, he reminded me, quite gently, that the rest of the world is not made up of "European or North American affluent white people who enjoy taking nature hikes."

"As the conservation movement has gotten outside of the U.S.," he said, "it's had its eyes opened to global realities, and the realities are that it's not about the affluent U.S. having nature reserves. It's about meeting lots of needs."

Some of those needs have been ignored ever since the U.S. first pushed Native Americans out of Yosemite, in 1864. "Fortress conservation," the practice of fencing off protected forest or savanna, has created a new class of "conservation refugees"—people forced from subsistence living within a landscape to straight-up poverty outside of it after it gets "preserved."