IN THE race to catalogue and protect biodiversity before it vanishes, history may offer the best guidance. The unenviable task of deciding how to spend precious conservation funds could be made easier by a technique that focuses on areas where the climate has remained stable for millennia.
That some regions of the Earth are rich in a wide variety of species is well known. But some , such as the Atlantic forests of Brazil, are in remote and little-studied tropical areas, leaving conservationists unsure as to where to best direct their efforts. 鈥淲e need to know at a much higher resolution where to invest,鈥� says Thomas Brooks, vice president of , based in Arlington, Virginia.
, an evolutionary biologist at the University of California, Berkeley, and her team are attempting to refine this targeting. They suggested that biodiversity is more likely to have flourished in regions with a long-term stable climate. To test this idea, the team used reconstructions of the climate in the Atlantic forest over the past 21,000 years. The central part of the forest, in Bahia, was the largest area with a stable climate, while areas in the south, near S茫o Paolo, had been less stable, they found (Science, ).
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If their hypothesis was correct, the central region would possess more diverse species than the south. To find out, they took genetic samples from three common species of tree frog found in both regions. Sure enough, their analysis revealed greater genetic diversity 鈥� which can only develop over a long period 鈥� in the frogs of the central region. 鈥淲e鈥檙e assuming the frogs are telling a story that鈥檚 applicable to the whole ecosystem,鈥� says Carnaval. Similar data on birds and lizards also revealed greater diversity in the central forest.
Conservationists, who have expended much of their effort on the southern Atlantic forest, may be missing the hotspot鈥檚 鈥渉ottest鈥� part.