On a typical mountain, every 1000 meters of elevation increase brings a temperature drop of 6°C. In the tropics, some species have evolved to live only in the cool-temperature oases of mountain peaks. It is these high-elevation species that stand a lot to lose as global warming heats up their habitats. AMNH researchers now suggest that climate change is already driving reptiles and amphibians that live on Madagascar's highest mountains toward extinction.
Chris Raxworthy, an Associate Curator of AMNH's Department of Herpetology, led a team that surveyed 30 species of chameleons, geckos, frogs, and other species living on northern Madagascar's Tsaratanana Mountains both in 1993 and 2003. Raxworthy discovered that overall, the species are gradually climbing to higher elevations in order to remain in the cooler temperature zones they require for survival.
Three of the species endemic to the very highest area of Tsaratanana's summit—meaning they do not live anywhere else—were not seen in 2003. This hints that they could already be extinct or are likely to become so before the century's end.
Onslope deforestation is further hindering the ability of these reptiles and amphibians to find the habitats they need. "The Malagasy government is creating important new reserves and protecting forests," says Raxworthy. "Yet with a phenomenon like global warming, this conservation problem requires a global solution." Extinctions of high-altitude species may be preventable if humans worldwide take dramatic action to reduce greenhouse gas emissions