Global warming could cause at least two toad species and one gecko species to go extinct by the end of this century as 30 species of reptiles and amphibians are moving uphill to find cooler temperatues, a biologist warns.
The animals that could go extinct are two species of narrow-mouth toads (Plethodontohyla tsarartananensis and Plethodontohyla sp. Z) and one species of gecko (Phelsuma l. punctulata) found in Madagascar's mountainous north, says researcher Christopher Raxworthy of the American Museum of Natural History.
Uphill movement is a predicted response to increased temperatures, Raxworthy says. Earlier studies in Costa Rica have provided evidence of how tropical animals respond to climate change.
The new research — based on surveys of Madagascar's amphibians and reptiles conducted in 1993 and 2003 and announced this week — extends that work, expanding the number and diversity of species that the trend affects, making a stronger link with meteorological changes, dealing with relatively large shifts in elevation, and assessing the extinction vulnerability for tropical communities in the mountains.
Two of these species were not found again during the most recent 2003 survey. (And for the 30 species that were re-sampled between 1993 and 2003, the majority are already moving upslope to compensate for habitat loss at lower and warmer altitudes.) Extinction is expected to occur between 2050 and 2100 if current trends persist, because there will eventually be no higher ground, predict Raxworthy and his colleagues from the Université d’Antananarivo in Madagascar, University of Michigan and University of Oxford.
The prediction is based on a conservative scenario in which warming remains below 2 degrees C (3 degrees F). Warming above 2 degrees C is considered to be dangerous in terms of impacts on biodiversity.
"Obviously, more warming will put more species at risk," Raxworthy told LiveScience. "Two things together — highly localized distribution close to the very highest summits, and the magnitude of these upslope shifts in response to ongoing warming — make a poisonous cocktail for extinction."
Source:Xinhua/Agencies
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