Environment

Lizards in peril

Audio: Play | Download

Audio clip: Adobe Flash Player (version 9 or above) is required to play this audio clip. Download the latest version here. You also need to have JavaScript enabled in your browser.

Download MP3
In recent decades, scientists have documented serious threats to frog species across the globe. Frogs and other amphibians have vanished from many areas. The exact cause is in question. It might be an infectious disease, or pollution, or habitat destruction. A study published by the journal Science suggests the world’s lizards are also in peril. And what’s threatening lizards is climate change. The World’s science correspondent Rhitu Chatterjee has the story.

• Science Magazine homepage
• World Science
• Download our science podcast

Read the Transcript
This text below is a phonetic transcript of a radio story broadcast by PRI’s THE WORLD. It has been created on deadline by a contractor for PRI. The transcript is included here to facilitate internet searches for audio content. Please report any transcribing errors to theworld@pri.org. This transcript may not be in its final form, and it may be updated. Please be aware that the authoritative record of material distributed by PRI’s THE WORLD is the program audio.

MARCO WERMAN:  I’m Marco Werman, this is The World.  Scientists know of serious threats to frog species across the globe.  They’re vanishing from many areas, though the exact cause is in question.  It could be disease or habitat destruction.  Now a study published by the Journal of Science suggests the world’s lizards are in peril because of climate change.  The World’s Science Correspondent, Rhitu Chatterjee has the story.

RHITU CHATTERJEE:  The European common lizard is a slender creature with a brown back and brightly colored belly.  And as its name implies, it’s found across Europe.  In the 1980′s scientists had documented the lizards in many parts of the Pyrenees mountain range in France.  But when ecologist Barry Sinervo of UC Santa Cruz went back to those locations in the 1990′s, he was surprised by what he found.

BARRY SINERVO:  I was in fact shocked.  They were extinct at many locations.

CHATTERJEE: Sinervo couldn’t find an obvious reason why the lizards had vanished from these areas.  The lizards do still live in some parts of the Pyrenees and the sites where they went extinct were pristine; undisturbed by development.  But there was something different about the areas that had lost their lizards.

SINERVO: They were all concentrated in the southern part of the range and at low elevation.

CHATTERJEE: In other words, these were relatively warm areas at the edge of the species range.  Maybe these areas were getting too warm.  Sinervo wondered if these lizards were dying off due to global warming.

SINERVO: So I thought well that’s interesting but it’s not like a global pattern.

CHATTERJEE: Then in 2006 Sinervo went to Mexico.  And he found the same pattern of local extinctions.  Mountain dwelling lizards were disappearing from the warmer edges of their ranges.  But was it really the heat that was killing them off?  Biologist Donald Miles of Ohio University examined that question.  He measured the air temperature of the sites where the lizards had vanished.  And indeed, for part of the year, these places were too hot for the lizards to survive.

DONALD MILES:  The extinct sites were thermally inhospitable so we got the smoking gun.

CHATTERJEE: Miles, Sinervo and their team wondered what these findings meant for lizards worldwide.  They scoured the literature for data on other lizards.  They applied what they had learned in Mexico and combined it with projections of future temperature increases.  And from that they made some predictions.  If nothing is done to curb global warming, nearly a fifth of all lizard species may go extinct by 2080.  Raymond Huey is a herpetologist at the University of Washington.  He calls the new study solid and important.

RAYMOND HUEY:  This is the first major paper to show that extinctions of lizards are not just for the future, but they’re here now.  I don’t think anyone had an appreciation of that on a global scale.

CHATTERJEE: And scientists say that it’s not just the lizards that are in trouble.  The problem is many species live in mountain ranges.  And as the temperature warms, these animals will have to move higher and higher up the mountains to find a more comfortable climate.  And soon, they could be left with nowhere else to go.  Stuart Pimm is a conservation biologist at Duke University.  He says the planet could warm by two degrees Celsius or more in the coming decades and that could cause large scale extinctions.

STUART PIMM:  The very substantial fraction of species around the world, maybe 25%, live within two degrees of their nearest mountain top, and that means those species are going to be in very serious trouble and it’s a very significant fraction of the world’s biodiversity.

CHATTERJEE: For now, these are only projections.  The big unknown is what the world will do to control the emissions that scientists say are already threatening species and entire ecosystems.  For The World, I’m Rhitu Chatterjee.

Copyright ©2009 PRI’s THE WORLD. All rights reserved. No quotes from the materials contained herein may be used in any media without attribution to PRI’s THE WORLD. This transcript may not be reproduced, in whole or in part, without prior written permission. For further information, please email The World’s Permissions Coordinator at theworld@pri.org.