Lizards, victims of global warming .

The blue lizard.Tags: Lizards, Warming, Jean Clobert.

A study shows that 20% of all of these reptiles could disappear from the planet by 2080.

The lizards are already paying a heavy price to global warming. About forty people followed in the Cevennes last ten years, four have disappeared. "The extinctions occurred each time after a period of high heat," said Jean Clobert, director of experimental ecology center at the CNRS in Moulis (Ariege). "Contrary to what we imagine, these little creatures that are fond of heat are very poorly equipped to face sudden changes in temperature." Lizards often seen motionless in the sun on rocks or walls are always finding an optimum temperature. Once it exceeds a critical threshold, they are threatened.
A study revealed that 4% of lizards disappeared since the 1970s in areas such as the Cevennes, and that 20% could disappear over the entire planet if the temperature curves continue to rise and emissions of greenhouse gases not are not limited. "If these projections are correct, the lizard could become the new amphibian extinctions in the race," write three American scientists specialists reptiles. In Mexico, where the warming is more pronounced than in many other areas of the world, extinctions have affected 12% of lizard populations.

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Although these animals are exposed to the sun for warmth, higher temperatures may force them to stay in the shade, limiting their search for food and can lead to burn all their reserves. They then die of desiccation. Their vulnerability is exacerbated by the fact that they cling to their environment. "Once the optimum temperature is exceeded, they go out at once," says Jean Clobert. The disappearances have been recorded in protected natural sites, the phenomenon can be attributed to habitat destruction. No infectious agent has been identified in these species, unlike amphibians, which are attacked by a formidable pathogen, the chytrid. A similar process could involve snakes, such as lizards, are exothermic and regulate their internal temperature with the external environment (sun, humidity, etc..).
The projections, based on observations and followed in several regions of the world since 1975, are then integrated in mathematical calculations. "Many people are skeptical about the models, admits Jean Clobert, but they represent years and years of work in a scientifically rigorous."
"I would rather not have written what I wrote there," says the researcher who was closely involved in the study led by Barry Sinervo, University of California at Santa Cruz (USA). Many of biodiversity research, published in major scientific journals, in fact a stand worrying. Jean Clobert co-signed an open letter to the President of the Republic where 60 biodiversity experts are alarmed by "the persistent disparity" between the "greatest threats facing our planet and the answers given so far.
The disappearance of lizard populations could affect the food chain and ecosystem. Insect predators, they are prey for many birds and snakes.