Study Says Global Warming Could Make Lizard Species Extinct

A team of international scientists is predicting global warming will wipe out nearly 40% of all lizard populations globally and 20% of all lizard species could become extinct by 2080, the authors said.

Lizards may not be cute and cuddly animals, but they are a valuable link in the global food chain, consuming large amounts of insects and serving as food for larger species. If they disappeared, the viability of other species could be threatened, the team reported in the journal Science.

Although lizards bask in the sun to keep warm, higher temperatures in recent decades exceed their physiological limits and keep them in the shade, the researchers said in a statement. Evolutionary biologist Barry Sinervo of UC Santa Cruz, the lead author of the report. "These lizards need to bask in the sun to warm up, but if it gets too hot they have to retreat into the shade and then they can't hunt for food," he said at a news conference.

The team found that, at the sites where extinctions were occurring, the number of hours per day the animals could spend in the sun had dropped sharply. "They would barely have been able to emerge to bask before having to retreat," Sinervo said.

The effects were most pronounced during the spring breeding season, when it is most important for the animals to eat lots of food to be able to produce offspring. If they can't produce the normal number of young, the population collapses.

Although most lizards evolve too slowly to adapt to the changes, some are able to survive by moving to higher altitudes where it is cooler. But the team found that this displaces other lizard species that normally live at those altitudes, leading to their loss.

Sinervo and his team maintain the loss of lizard populations is not due to habitat loss, because the places where they are not seen any more are in undisturbed places like national parks and sanctuaries.

The researchers "deliver a disturbing message," biologist Raymond B. Huey of the University of Washington and his colleagues wrote in an editorial accompanying the report. "Climate-forced extinctions are not only in the future, but are happening now."

The study is published in the May 14 issue of the journal Science.

Source:
All Headline News, "Study Says Global Warming Could Make Lizard Species Extinct", accessed May 15, 2010
LA Times, "Quantcast Lizards face extinction because of global warming, study finds", accessed May 15, 2010