Climate Change Could Kill 40 Percent of World's Lizard Population by 2080

Climate models predict that the global population of lizards will be reduced by 2080 due to climate change. However, a new study revealed that the effects of global warming to the lizards might be worse than what was previously thought.

The study, published in the journal Proceedings to the National Academy of Sciences, suggests that more data is regarding the distribution of shade in the lizard's habitat is necessary to make accurate predictions of the lizard's future population.

"The real fear is that previous research has underestimated the risk of extinction," explained Mike Angilleta, a professor at Arizona State University and co-author of the study, in a statement. "Most models assume that an animal can be anywhere in its environment at any time, which doesn't account for how much energy an animal spends to regulate its temperature. Animals have to move and search for shade, which makes cooling down more difficult when patches of shade are far apart."

Lizards, like other reptiles, rely on external factors to regulate their body temperature. They warm up their body by basking in the sun and cool it down by resting at the shade.

For the new study, the researchers developed computer simulations involving digital lizards in a virtual environment. Using these simulations, the researchers were able to determine how much energy a lizard spent on regulating their body temperatures when shade was either clumped or spaced apart.

The researchers discovered that lizards were able to regulate their temperatures more efficiently when the shades were dispersed in their environment. Less energy is required to move from patch to patch. On the other hand, when the shade was isolated in one location, lizards needed to move further away to hunt for food, using more energy to travel from their feeding area back to the isolated shade.

To mimic their computer simulation, the researchers build 20 by 20 meter square fenced arenas that are either by one big clump of cloth, four-medium-sized patches or 16 small patches of shade. Lizards are then left for two days inside each environment.

Lizards left under the big clump of cloth have temperatures varied by 12 percent more when they are left in the four medium-sized patches and 10 percent more when they are in the small patches. This suggests that more patches or shades in the lizard's habitat provide better and more careful thermoregulation.