In the field of conservation, success stories about saving individual species abound. Bald eagles have recovered from their bout with the pesticide DDT; from fewer than 500 breeding pairs in 1963, the population in the lower 48 states has grown to nearly 10,000 breeding pairs, such that they are no longer listed even as threatened under the Endangered Species Act. Gray wolves have returned to Yellowstone National Park, as well as to the Italian and French Alps. The California condor has been brought back from the absolute brink of extinction, after the last surviving birds were rounded up and bred in the San Diego and Los Angeles zoos. And so on.

When human ingenuity and resources are trained on a particular species, usually a charismatic one, it makes a difference—but it does not change the global pattern, which is a steady drumbeat of extinction and of the permanent loss of biodiversity that goes with it. In a recent global assessment, Stuart Butchart and his colleagues at BirdLife International in England concluded that between 1994 and 2004 conservation efforts had saved 16 species of bird from extinction, at least temporarily. During that same decade, however, another 164 bird species listed as threatened by the International Union for Conservation of Nature (IUCN) had slipped a notch closer to extinction.

Conservationists have many priorities and many strategies. But for the past two decades, a leading priority has been to preserve as much biodiversity as possible, and the most prominent strategy has been to focus on “hotspots”—regions of the world, such as tropical rain forests, that are rich in species and yet losing them fast. The strategy has been arguably successful, yet it has also been controversial.

“The most difficult challenge we face as conservationists today is to answer the question, Why does biodiversity matter?” says Mike Hoffmann, an ecologist based at Conservation International (CI), an organization that has made hotspots the centerpiece of its efforts. All conservationists oppose extinction, it seems, in the same way that they favor apple pie. But not all agree that saving the maximum number of species worldwide should be the number-one priority—or that preserving hotspots on our increasingly crowded planet leads to the best of all possible worlds.

Defining Diversity
The word “biodiversity” first appeared in print in 1988, as the title of a National Research Council report edited by Harvard University entomologist E. O. Wilson. In the opening chapter Wilson guessed that the earth held between five million and 30 million species, more than half of them living in tropical rain forests. “From a single leguminous tree in the Tambopata Reserve of Peru,” he wrote, “I recently recovered 43 species of ants belonging to 26 genera, about equal to the entire ant fauna of the British Isles.” He went on to make an equally rough estimate of how many species the earth was losing to extinction: about one every half an hour. Most were undescribed tropical insects vanishing without witness.

Wilson’s calculation was based on his theory of “island biogeography,” which predicts how many species can survive in a given area of isolated or fragmented habitat, and on estimates of how much rain forest was being cut down. An area the size of West Virginia, Wilson said, was being lost every year—confirming predictions made a decade earlier by a British researcher named Norman Myers. Those predictions had been dismissed by some of his peers as alarmist, but it became clear they were not: human beings were causing a mass extinction unparalleled since the demise of the dinosaurs 65 million years ago.

Over in species-poor Britain, Myers was also coining a new term in 1988—new at least to conservation biology—and it would soon become a buzzword, too: “hotspots.” Myers is an independent environmental consultant, an adjunct academic, notably at the University of Oxford, and a self-described “lone wolf.” After previous lives as a schoolteacher in colonial Kenya and then as a photographer of African wildlife, he had earned a Ph.D. at the University of California, Berkeley, in the early 1970s and moved into conservation work. By the late 1980s he was frustrated. “It struck me that because of sheer shortage of funds, scientific expertise and government attention, we were not helping many species all that much,” Myers recalls. “We were spreading ourselves far too thinly.”

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Hotspots were his solution: If you had limited resources and wanted to preserve the maximum number of species, Myers reasoned, you should concentrate on regions that had the most “endemic” species—species that were not found elsewhere—and that were losing them fastest. In his 1988 paper Myers identified 10 such hotspots, all of them centered on tropical forests. Two years later he added eight more to the list, including four regions with Mediterranean climates—subtropical grasslands that were under intense pressure from humans.

The hotspot concept caught on almost immediately. From 1990 on the Mac­Arthur Foundation supported hotspot preservation to the tune of $15 million a year. Later the idea was adopted by CI, which had initially been formed by defectors from the Nature Conservancy and the World Wildlife Fund. Those older organizations had also been concerned with preventing extinctions, but CI made the preservation of global biodiversity—that is, the total number of species—its main focus. Working with Myers, it refined his concept, defining a hotspot as a region that had at least 1,500 species of endemic plants (0.5 percent of the world’s total) and that had lost at least 70 percent of its original vegetation. Hotspots brought a welcome rigor to conservation biology, says Peter Kareiva, chief scientist of the Nature Conservancy. “There was a sense before that conservation was ad hoc—that it was about this pretty place or that charismatic animal. The good thing about hotspots is that they were the beginning of being analytical.”

Above all, hotspots made sense to the World Bank and to the foundations that have become increasingly important supporters of conservation work. Even people in the business of healing the world’s pain do not like feeling they are pouring money down a bottomless hole. Hotspots divided a vast and intractable problem into more manageable parts, with definable targets, and that made foundation managers want to sign checks. Ask Myers today, 20 years after he hatched his simple little idea, which of its impacts he is proudest of, and he says this: “The mobilizing of $850 million.” It is indeed an astonishing sum. CI, which has received much of it into its Critical Ecosystem Partnership Fund, had fewer than 100 employees in 1990; it now has about 900 in locations all over the world. Recently it increased the number of hot­spots to 34. “If our number-one priority is to save as many species as possible, I don’t see how you can do much better than hotspots,” Myers says.

Focusing Aid and Attention
Hotspots, as Myers and CI define them, are large regions—Central America is one, for instance, as is Madagascar. Within those regions, various conservation strategies are possible, including captive breeding programs for particular species. But because habitat loss is generally the gravest threat, the most obvious strategy is to designate smaller, even hotter spots within those regions as “protected areas.” Beside its “Red List” of threatened species, the IUCN also maintains, along with the United Nations, a list of protected areas. They number over 100,000 and cover 11.5 percent of the earth’s land surface.

But many, especially in the poorer tropical countries, are what conservationists call “paper parks”—parks in name only. A few years ago Ana Rodrigues of CI and her colleagues compared the ranges of 11,633 species of terrestrial vertebrates with the geographic coverage of the protected areas. They found that a minimum of more than 12 percent of vertebrates—­1,483 species, including 833 listed as threatened by the IUCN—fell into gaps between the parks and thus had no protection at all. Mammals fared the best, amphibians the worst, presumably because people care more about mammals and because amphibians tend to have smaller ranges that are less likely to overlap with a park.

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Thus, a large gap exists between conservation need and conservation resources: compared with what it would take to prevent the mass extinction that is now under way, $850 million spread over many years is actually a tiny sum. People such as John Watkin, an ecologist who is also a grant director for the Critical Ecosystem Partnership Fund, feel that gap acutely. “I’m a huge advocate of the hotspots approach,” he said recently. He was speaking on his cell phone, stuck in what he said was “the longest traffic jam in my life,” on a bus that was taking him from Arusha, Tanzania, to Nairobi, Kenya. Hotspots, such as the Eastern Arc Mountains of those two countries, are not wilderness areas; on the contrary they are areas that are being crushed by a needy humanity. “When I first joined [Conservation International], I was very skeptical of hotspots,” Watkin went on. “I’ve been turned around by looking at the financial resources. Everybody has to draw a line in the sand somewhere.”

Biodiversity hotspots channel resources to places that need it most, Watkin observed—not only away from the temperate-latitude industrial countries, which are richer in cash than in creatures, but away from “the Serengeti and the other established reserves that have been popularized by research and tourism.” At the northern end of the Eastern Arc Mountains, for instance, CI is working to protect the cloud forests of the Taita Hills. Ninety-eight percent of the forest has been cut down, mostly in the past 40 years, to make way for agriculture; a little more than 1,000 acres are left, a dozen small islands in a sea of farmland and exotic tree plantations. No lions, elephants or giraffes live in the Taita Hills; there are not even gorillas, but there are three species of bird that live only in those beleaguered islands. Saving those birds means saving what is left of the forests.

Saving the Picassos
In that sense, the forest islands are irreplaceable—which is the essential feature of hotspots. The concrete criteria for choosing hotspots are just convenient ways of measuring irreplaceability and threat, Hoffmann says, and they work. Threatened vertebrate species may be falling freely through the gaps in the protected-area network, but three quarters of such species are found in hotspots and nowhere else on the earth—indicating that hotspots are good places to protect more land and in general to focus efforts at saving vertebrates as well as plants. “We believe everything can be saved,” Hoffmann says. “It’s about where you go first. If we fail in the hot­spots, half of biodiversity is gone. Finished.”

The fear of that finality is something that drives most conservation biologists, including some who are critical of the hotspot approach. “There is nothing as bad as losing species,” says Walter Jetz, an ecologist at the University of California, San Diego. “They are unique biological entities, with unique evolutionary histories and a set of functions we have only partly understood.” People will rush back into burning houses to retrieve family photographs and heirlooms; something like that emotion stirs in the hearts of conservation biologists when they contemplate the irreversible loss that is extinction—although Jetz compares species to Picassos, not snap­­shots. Jetz grew up in Bavaria, saw how much money was spent there conserving relatively little biodiversity, then plunged as a young scientist into the teeming tropics of central Africa. He wholeheartedly endorses the transfer of conservation resources from North to South.

But Central Africa is a case in point: it is not on the hotspot list, because it is still in relatively good shape. In revising its list, CI also created a parallel list of five “wilderness areas,” including the Congo Basin, but it devotes far fewer resources to them. Conservation efforts in general tend to focus on areas that have suffered heavy human impact in the past—but those areas, Jetz and his graduate student Tien Ming Lee concluded in a study published this year, often are not the areas projected to suffer the heaviest impacts in the future. Central Africa, for instance, still retains most of its original forest, but in recent decades industrial logging concessions have been granted to more than 30 percent of it, and only 12 percent is protected. “That’s potentially a hotspot for conservation,” Jetz says. “Future challenges to conservation may not have much to do with the past.”

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Especially when global warming enters the equation: no one really knows what to do about it. In mapping out the future high-impact areas, Jetz and Lee considered the effects of climate change on vegetation but not its effects on the ranges of animals, because too little is known about that. A study published in Nature in 2004, however, predicted that by 2050 between 15 and 37 percent of the species on the earth might be “committed to extinction” as a result of climate change alone. Those alarming numbers were contested—but not the basic reality that no area on the earth can be completely protected anymore. Carbon dioxide (CO2) from fossil fuels warms the planet everywhere, and it will change habitats everywhere, including ones we are not destroying in a more direct way.

That doesn’t mean stopping the destruction isn’t a good idea, of course—it is, not only because it protects habitats but because it curbs the deforestation that is itself a huge source of CO2. Expanding the focus of conservation beyond hotspots, however, does mean that the entire rationale behind parks and other protected areas is going to need to be rethought for a warming world. “Unless you worry some about the area between the reserves, species won’t be able to move,” Kareiva says. The Nature Conservancy has been focusing much of its efforts lately on creating migration corridors. “Thinking only about parks leads people to pay not enough attention to the rest of the world,” he adds.

“Protected areas are just a tool, not a goal,” says Luigi Boitani, a biologist at the University of Rome “La Sapienza” who has spent decades studying the wolves and bears of Italy. He participated with Rodrigues in the analysis of gaps in the existing protected area network, and he thinks the explicit purpose of such reserves should be to preserve biodiversity. But reserves are not the final answer, he says: “By setting aside 10 percent of the world, we are far from saving the world. Protected areas are useless if we don’t find a broad agreement between humans and nature.

“We have wolves 20 minutes from the Coliseum,” he goes on. “Bears an hour from downtown Rome. I must believe in coexistence.” If the carnivores are spreading once again in Italy, he says, it’s not because they are being protected in parks—it’s because the government compensates farmers for lost livestock, subsidizes guard dogs and electric fences, and in general encourages Italians to live alongside the beasts, not shoot them.

Warming Up to Coldspots
Coexistence between humans and nature can be encouraged in biodiversity hot­spots, too. In the Taita Hills, Watkin and Conservation International are trying not so much to create forest reserves as to get people to respect reserves that already exist. To that end, they are involving the local population in the conservation strategy, and they are funding projects designed, as Watkin puts it, “to provide very realistic alternatives to chopping down the forest and making charcoal.” Farming butterflies or indigenous silkworms, for instance: both can be done without en­croaching further on the cloud forest, and both have become significant moneymakers for the Taita Hills.

Much good conservation work has been done and continues to be done as a re­­sult of the hotspot approach; that $850 million has been put to good use. Yet the same critique Kareiva and Boitani direct at parks applies, on a larger scale, to hot­spots: that they lead people to not pay enough attention to the rest of the world—to the “coldspots,” as Kareiva calls them. Hotspots are hot because they are rich in endemic species and because Myers and CI define the top priority as preserving the maximum number of species on the whole planet.

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The main argument for this view, aside from the moral one that it is wrong for us to extinguish any species, is that species diversity keeps ecosystems functioning. Functioning ecosystems in turn provide eco­­nomically valuable services; for instance, healthy forests around cities keep local water supplies clean. Hard scientific data back up both those claims—but only at the level of individual ecosystems, not the whole planet. “There is not a single scientific paper that shows a loss of ecosystem services when you change the total global number of species,” Kareiva says.

The hotspot concept, he goes on, “doesn’t have a scientific basis at all. When we say we care about biodiversity, we mean wherever you live, Montana or Tanz­ania, you don’t want to lose so many species that your ecosystem just won’t function. The goal might be, nowhere in the world do we lose half our species. If we lose that much, that place is gone.” Boi­tani’s long-term priority is similar. It is “to find a stable relationship between humans and other species,” he says. “Stop the negative trend. Find a relation of coexistence and tolerance, even if it means we have to lose 50 percent of the species. I’m ready to sign off  on that if it means what is left will last.”

That view is anathema to hotspot proponents. “The notion that biodiversity loss of any kind is acceptable is just not acceptable,” Hoffmann says. “We don’t believe that extinction is inevitable—human-mediated, fast-tracked extinction should not be inevitable.” From that standpoint, accepting the reality that we are causing extinctions every day and, as global warming accelerates, are soon going to be causing many more is unforgivably unambitious. The counterargument is that trying to preserve the whole planet in some kind of ecologically intact form is in fact far more ambitious than just focusing on the 2 percent of land surface that happens to be in hotspots.

Biodiversity hotspots were a useful conceptual shortcut—a quick way of figuring out where to begin with the daunting task of saving the world. By focusing efforts on the total number of species, they allow conservationists to avoid the hard science required to decide which species matter most to ecosystems and the hard choices required to decide which species matter most to us. But we’ll come closer to making real conservation progress, say Kareiva and other scientists, when we face up to those choices. “We’re the stewards of the planet,” Kareiva declares. “We get to choose its future. Let’s admit that.”

Note: This article was originally printed with the title, "Are Hot Spots Key to Conservation?"