Shrinking of North American Salamanders Linked to Climate Change [VIDEO]
As the climate gets warmer and drier, salamanders in North America are getting smaller, according to a new study.
Some of the best salamander habitat in North America, the Appalachian Mountains, are getting warmer and drier as a result of climate change and the salamanders native to the region are being affected.
Writing in the journal Global Change Biology study co-author and Clemson University biologist Michael Sears and his colleagues report on museum specimens of wild-caught salamanders collected in the Appalachian Mountains from 1957 to 2007 and wild specimens caught and measured in 2011-2012 at the same sites as the earlier specimens.
The salamanders collected from 1980 onward were, on average, 8 percent smaller than their counterparts from earlier decades. The size changes were most pronounced in the Southern Appalachians, where climate data reveals greatest warming and drying.
"One of the stresses that warmer climates will impose on many organisms is warmer body temperatures," Sears said. "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."
The researchers then developed a computer model that they could program to estimate a salamander's typical daily activity and energy expenditure. Weather data was incorporated into the model to give the researchers a day-to-day idea of the conditions the salamanders faced as they went about their day. The simulation revealed the modem salamanders to be just as active as salamanders from decades past, despite a warmer and drier habitat.
"Ectothermic organisms, such as salamanders, cannot produce their own body heat," Sears said. "Their metabolism speeds up as temperatures rise, causing a salamander to burn 7 to 8 percent more energy in order to maintain the same activity as their forebears."
Karen Lips, a University of Maryland biologist and study co-author said that the changing body size of the salamander is one of the largest and fastest ever recorded in any animal.
"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," Lips said. "If these animals are adjusting, it gives us hope that some species are going to be able to keep up with climate change."