"Salamanders shrinking as their mountain havens heat up"

March 2014

"Salamanders shrinking as their mountain havens heat up"

Link: http://www.sciencedaily.com/releases/2014/03/140325154230.htm

     Salamanders in some of North America's best habitat are shrinking fast as their surroundings get warmer and drier. As a result, the salamanders are forced to burn more energy. Specimens caught in the Appalachian Mountains from 1957 to 2007 and wild salamanders caught at the same sites in 2011-2012 have recently been studied. Animals measured after 1980 averaged 8 percent smaller than those caught in 2011-2012 - one of the fastest rates of changing body size ever recorded.
     The study was prompted by the work of University of Maryland Prof. Emeritus Richard Highton and headed by Karen R. Lips, an associate professor of biology at the University of Maryland. The study found that between 1957 and 2012, six salamander species got significantly smaller, while only one got slightly larger. On average, each generation was one percent smaller than its parents' generation, the researchers found.The researchers compared changes in body size to the animals' location and their sites' elevation, temperature and rainfall. They found the salamanders shrank the most at southerly sites, where temperatures rose and rainfall decreased over the 55-year study.
     Furthermore, to discover how climate change affected the animals, Clemson University biologist Michael W. 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 behavior of individual salamanders. The simulation showed the modern salamanders were just as active as their forbears had been. But to maintain that activity, they had to burn 7 to 8 percent more energy and Sears explained that cold-blooded animals' metabolisms speed up as temperatures rise. In order to get the extra needed energy, salamanders may spend more time foraging for food or resting in cool ponds, and less time hunting for mates. The smaller animals may have fewer young, and may be more easily picked off by predators.