World’s lizards disappearing due to rise in global temperatures

May 14th, 2010 - 1:21 pm ICT by ANI  

Washington, May 14 (ANI): Rising temperature is adversely affecting the lizard population, so much so, that a full 20 percent of all lizard species could be extinct by the year 2080, a new study claims.

An international research team, which surveyed Sceloporus lizard populations in Mexico for decades, has found that rising temperatures have driven 12 percent of the country’s lizard populations to extinction.

The detailed surveys of lizard populations in Mexico, collected from 200 different sites, indicate that the temperatures in those regions have changed too rapidly for the lizards to keep pace.

It seems that all types of lizards are far more susceptible to climate-warming extinction than previously thought because many species are already living right at the edge of their thermal limits, especially at low elevation and low latitude range limits.

Although the researchers’ prediction for 2080 could change if humans are able to slow global climate warming, it does appear that lizards have crossed a threshold for extinctions-and that their sharp decline will continue for decades at least.

Barry Sinervo from the Department of Ecology and Evolutionary Biology at the University of California in Santa Cruz, along with colleagues from across the globe, reached these conclusions after comparing their field studies of the lizards in Mexico with extensive data from around the world. Their research will be published in the May 14 issue of Science, the peer-reviewed journal published by AAAS, the nonprofit science society.

After compiling the global field data, Sinervo and his colleagues studied the effects of rising temperatures on lizards’ bodies, and created a model of extinction risks for various lizard species around the world.

Sinervo said: “How quickly can Earth’s lizards adapt to the rising global temperatures? That’s the important question. We are actually seeing lowland species moving upward in elevation, slowly driving upland species extinct, and if the upland species can’t evolve fast enough then they’re going to continue to go extinct.”

The detailed study notes specifically that lizards that bear live young are particularly at risk of extinction, compared to those that lay eggs.

Sinervo added: “Live-bearers experience almost twice the risk of egg-layers largely because live-bearers have evolved lower body temperatures that heighten extinction risk. We are literally watching these species disappear before our eyes.

In order to fine-tune their model with this surprising global outpouring of data, Sinervo and his colleagues used a small electronic device that mimics the body temperature of a lizard basking in the sun. They placed these thermal models in sun-drenched areas for four months at sites in Mexico where lizard populations were still thriving-and at sites where they have already gone extinct.

Sinervo briefed: “There are periods of the day when lizards can’t be out, and essentially have to retreat to cooler places. When they’re not out and about, lizards aren’t foraging for food. So we assessed how many hours of the day lizards would have been driven out of the sun at these different locations. Then, we were able to parameterize our global model.”

The experts claim these findings are both “devastating and heart-wrenching.”

However, hope hasn’t ended for the world’s lizards.

Sinervo concluded: “If the governments of the world can implement a concerted change to limit our carbon dioxide emissions, then we could bend the curve and hold levels of extinction to the 2050 scenarios. But it has to be a global push… I don’t want to tell my child that we once had a chance to save these lizards, but we didn’t. I want to do my best to save them while I can.” (ANI)

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