Washington, June 10 : A new research has determined that climate change has hastened extinction in Madagascar's reptiles and amphibians, with three species in the region predicted to go extinct between 2050 and 2100 because of habitat loss associated with rising global temperatures.
The research, conducted by the American Museum of Natural History in the US, also provides the first detailed study showing that global warming forces species to move up tropical mountains as their habitats shift upward.
These species, currently moving upslope to compensate for habitat loss at lower and warmer altitudes, will eventually have no place to move to.
Uphill movement is a predicted response to increased temperatures, and other studies have provided some empirical evidence of how tropical animals respond to climate change.
Christopher Raxworthy, Associate Curator in the Department of Herpetology, has been surveying the diversity of Madagascar's herpetological assemblage since 1985 and discovered the uphill migration almost by chance while in the field. n repeated surveys of northern Madagascar's mountains, the Tsaratanana Massif, he noticed that some species were missing from camps where they'd been previously observed.
Moreover, some of these "missing" species popped up at the next higher elevation surveyed.
"I noted this in the field as strange, but when I later sat down and looked at the data, the trend persisted," explained Raxworthy.
He culled elevation records and was able to compare surveys of animals over a ten-year period.
The results were dramatic.
Among 30 species of geckos, skinks, chameleons, and frogs, and controlling for sampling effort, an average shift uphill of 19 to 51 meters (62 to 167 feet) was observed over the decade.
When these results were compared with meteorological records and climate change simulations, the movement of animals could be linked to temperature increases of 0.1°C to 0.37°C over the same decade, which corresponds to an expected upslope movement of 17 to 74 meters (59 to 243 feet).
These animals come from five different families of amphibians and reptiles-narrow-mouthed toads, mantelline frogs, chameleons, geckos, and skinks-making it unlikely that a simple phenological change could explain the upward movement.
"When you see a general trend across all these groups of organisms, it is likely to be related to a broad explanation like general temperature warming, not something more subtle such as seasonal variation," said Raxworthy.
"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," said Christopher Raxworthy, Associate Curator in the Department of Herpetology.