A group of scientists studying the impact of global warming on the Earth's lizard populations warns that current climate models might not be enough to accurately predict the fate of the scaly critters in the coming years.
Previous studies have suggested that at the rate of warming the planet is experiencing, lizard populations won't be able to adapt fast enough to keep up with the drastic changes in their environment, resulting in the loss of as much as 40 percent of their numbers around the world by 2080.
However, researchers at Clemson University and Arizona State University (ASU) said that many of the models used for such predictions failed to include enough data on how shade is distributed in lizard habitats.
Michael Sears, a biology professor at Clemson and lead author of the study, pointed out that these earlier studies assumed that lizards can easily shade anywhere in their environment whenever they needed it, but in actuality it is much more complicated than that.
He said many of these lizards spend significant time and energy in order to find shade to hide in. This means that the models used to predict the animals' extinction might not be as accurate as previously thought.
The Importance Of Shade Distribution
Through the use of computer modeling and data from real-world experiments, Sears and his colleagues examined how the kind of shade available to lizard populations in the New Mexico desert impacts their ability to maintain the temperature of their bodies in an optimal range.
The researchers surgically placed small sensors into the bodies of spiny lizards to monitor changes in their temperatures. They then subjected the animals to experiments in special enclosures in the desert.
Sears said they used pieces of shade cloth in order to cool down the lizards' body temperatures in certain areas to find out how they will react to it.
The researchers discovered that the spiny lizards fared much better when they were able to access a number of small shade patches than when they were able to stay in only a few large patches.
Sears explained that this can be compared to when a person goes out jogging on a hot day and only finds one tree with shade along the way. This could be considered a bad environment to be in.
However, if there were more trees along the way that could provide even a small amount of shade, it would be more convenient for the jogger.
The results of the study show that determining the future of lizard populations in relation to the ongoing global warming might be more complicated than researcher initially thought. The distribution of shade provided by various plants and rocky structures could significantly affect the chances for survival for these animals.
Sears said lizards that already live in hot regions will likely suffer the most from severe temperature increases, while those that live in cool regions will likely experience some form of benefit to a certain extent.
The findings of the Clemson University and Arizona State University study are featured in the journal Proceedings of the National Academy of Science.
Photo: Renee Grayson | Flickr
