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'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."
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 Mac Arthur 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 hot spots 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.
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.
You can continue reading this article at http://www.sciam.com/article.cfm?id=is-focusing-on-hot-spots&page=3
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