Losing the Lizards: study indicates climate change can lead to global extinctions

According to a new study published last week in Science Magazine, lizards are at a high risk of extinction due to climate change. With rising temperatures, they will spend more time seeking shade and less time feeding and breeding to perpetuate the species.

Researcher Barry Sinervo of the University of Santa Cruz and his colleagues compiled data that included local population extinctions to date, climate temperature changes, and the known temperature ranges or requirements of lizard species to construct predictive models.

The research study indicates that, since 1975, local population extinctions had reached 4% worldwide and that global extinction of entire species could reach 20% by 2080 based on current rates of temperature increase.

Ever seen a lizard sunning itself? It's not actually just sunbathing or taking a snooze. As a cold-blooded "ecotherm", it is, in essence, charging its battery so that it can engage in the important activities of foraging for food and breeding. But it does so within a particular range of temperature. And since it can not sweat or pant to cool off, when it becomes too hot it heads for shade or burrows to cool down.

But when lizards are spending more time seeking cooler conditions, they are not engaged in the activities that will guarantee their long-term survival.

"So they don't die directly but they can't reproduce. It only takes a couple of generations of that and the population is going to spiral downward until it goes extinct," says Jack Sites, one of the study's collaborators and a herpetologist from Brigham Young University.

Lizards play an important role in nature's food chain, feeding on insects and being a food source for larger animals like birds. Their loss would definitely have a severe impact on local ecosystems but just how devastating that would be is hard to determine. It is something that scientists, like Sinervo, would prefer not to have to find out.

"The numbers are actually pretty scary. We've got to try to limit climate change impacts right now or we are sending a whole bunch of species into oblivion," Sinervo said.

Read the Science Magazine abstract/article.
Read MNN article about the study.