Wild salamanders living in some of North America’s best salamander habitat are getting smaller as their surroundings get warmer and drier, forcing them to burn more energy in a changing climate.
That’s the key finding of a new study co-authored by a Clemson University biologist and published Tuesday in the journal Global Change Biology that examined museum specimens caught in the Appalachian Mountains from 1957 to 2007 and wild salamanders measured at the same sites in 2011-2012.
The salamanders studied from 1980 onward were, on average, eight percent smaller than their counterparts from earlier decades. The changes were most marked in the Southern Appalachians and at low elevations, settings where detailed weather records showed the climate has warmed and dried out most.
“One of the stresses that warmer climates will impose on many organisms is warmer body temperatures,” said Michael W. Sears of the biological sciences department. “These warmer body temperatures cause animals to burn more energy while performing their normal activities. All else being equal, this means that there is less energy for growth.”
To find out how climate change affected the animals, Sears used a computer program to create an artificial salamander, which allowed him to estimate a typical salamander’s daily activity and the number of calories it burned.
Using detailed weather records for the study sites, Sears was able to simulate the minute-by-minute behavior of individual salamanders based on weather conditions at their home sites during their lifetimes. The simulation showed that modern salamanders were just as active as their ancestors had been.
“Ectothermic organisms, such as salamanders, cannot produce their own body heat,” Sears explained. “Their metabolism speeds up as temperatures rise, causing a salamander to burn seven to eight percent more energy in order to maintain the same activity as their forebears.”
The changing body size of salamanders is one of the largest and fastest rates of change ever recorded in any animal and the data recorded in this study reveals that it is clearly correlated with climate change, according to Karen R. Lips, associate professor at the University of Maryland’s (UMD) department of biology and co-author on the paper.
“We do not know if decreased body size is a genetic change or a sign that the animals are flexible enough to adjust to new conditions,” said Lips. “If these animals are adjusting, it gives us hope that some species are going to be able to keep up with climate change.”
The research team’s next step will be to compare the salamander species that are getting smaller to the ones that are disappearing from parts of their range. If they match, the team will be one step closer to understanding why salamanders are declining in a part of the world that once was a haven for them.
This material is based upon work supported by the University of Maryland and Smithsonian Institution Seed Grant Program. Any opinions, findings and conclusions or recommendations expressed in this material are those of the authors and do not necessarily reflect the views of the University of Maryland and Smithsonian Institution Seed Grant Program.
Links for further reading:
The Associated Press (6.29.2014): Study: Salamanders in the Appalachians are smaller, Full story
This AP story was picked up by major media outlets including The New York Times, The Washington Post, ABC News, French Tribune, Miami Herald, Charlotte Observer, The State and Houston Chronicle, among many others.
People Behind the Science (5.27.2014): Dr. Mike Sears: A Super Modeler of Thermal Adaptation, Listen now.
The New York Times (4.7.2014): Salamander’s Hefty Role in the Forest, Full Story
BuzzFeed (4.1.2014): 13 Important Things Science Taught Us In March, Full Story
Scientific American (3.27.2014): Salamander Shrinkage Linked to Climate Change, Full Story
National Geographic (3.27.2014): Climate Change Shrinks Salamanders, Full Story
ScienceBlogs (3.27.2014): Alarming Rates Of Climate Change Caused Alarming Change in Salamanders, Full Story
Salon (3.27.2014): “Salamander shrinkage” is the latest potential effect of climate change, Full Story
Nature (3.26.2014): Salamander shrinkage linked to climate change, Full Story
The Christian Science Monitor (3.26.2014): Climate change makes salamanders shrink, scientists say, Full Story
BBC Nature (3.26.2014): Salamanders shrink as mountain home heats up, Full Story
International Business Times (3.26.2014): US Salamanders ‘Shrinking?’ Study Suggests ‘Clear’ Correlation To Climate Change, Full Story
United Press International (3.26.2014): Why are salamanders in the Eastern U.S. shrinking? Full Story
Headlines & Global News (3.26.2014): Salamanders Shrinking Because Of Climate Change; 8 Percent Smaller Than In 1980s, Full Story
The Weather Channel (3.26.2014): Climate Change is Making Salamanders Shrink, Study Shows, Full Story
Austrian Tribune (3.26.2014): Climate Change causing Shrinkage in Appalachia‘s Salamanders, Full Story
The Huffington Post (3.26.2014): Salamanders Are Shrinking, Thanks To Climate Change, Full Story
University Herald (3.26.2014): As The World Gets Hotter, Salamanders Get Smaller, Full Story
Nature World News (3.25.2014): Shrinking of North American Salamanders Linked to Climate Change, Full Story
NBC News (3.25.2014): Salamanders Are Shrinking As Their Habitats Warm Up, Full Story
Science News (3.25.2014): Warming World Shrinks Salamanders, Full Story
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