Salamanders are Shrinking Due to Impact of Climate Change, Study

Global warming has not only affected humans but also the wild salamanders in the Appalachian Mountains, a latest research claims.

Researchers at the University of Maryland say the population of wild salamanders living in North America's best salamander habitat are bearing the brunt of climate change. These nocturnal amphibians are shrinking in size as a result of drastic climate change. Reason being that the  warm and dry surrounding are forcing the species to burn more energy.

The findings are based on the analysis of museum specimens from the Appalachian Mountain, a hot spot for a variety of salamander species. They analysed the salamanders caught from 1957-2007 and 2011-2012 at the same site and noticed a remarkable difference in the salamanders present in the South Appalachians and those at lower elevations. More than half of these lizard-like amphibians were 8 percent smaller than their counterparts that were collected before the 1980s. This drastic change in the size of the amphibians is blamed on climate change.

"This is one of the largest and fastest rates of change ever recorded in any animal," Karen R. Lips, an associate professor of biology at the University of Maryland, said in a news release. "We don't know exactly how or why it's happening, but our data show it is clearly correlated with climate change."

The researchers are uncertain on whether this change in size is a result of genetic  change or an indication of the amphibian's adaptationto the changing environmental conditions. But if these amphibians are adjusting to the changing scenarios, it gives a positive hope that the species will survive this rapidly changing climate.

This finding is based on the study that was initiated in 1957 by University of Maryland Prof. Emeritus Richard Highton. Thousands of salamander samples he collected from the Appalachian Mountains in 1957 showed a drastic decline in size. Further investigations into the cause ruled out the possibility of a lethal fungal disease, which was the reason for decline in frog species. This was confirmed by the DNA sampling done in 2011 and 2012.

The researchers observed that on an average each generation was one percent smaller than the earlier generation and most of it was seen in the Southern Appalachians, where there was a rise in temperature and decrease in rainfall.

To test this geographical divide, they created artificial salamanders using a computer program and simulated their daily routine and calculated the number of calories they burnt. Weather records of the previous years were also factored. They noticed that the modern salamanders were equally active as their earlier counterparts. They burned 708 percent of more energy for their activity. In cold blooded animals as the temperatures rise the body metabolism also increases.

For this extra energy, their foraging activities increased and they spent less time hunting for mates. Smaller salamanders have fewer young ones and are easily picked by the large predators.

"Right now we don't know what this means for the animals," Lips said. "If they can start breeding smaller, at a younger age, that might be the best way to adapt to this warmer, drier world. Or it may be tied in with the losses of some of these species."

The team next plans to compare the salamander species that are shrinking to the ones that are vanishing from their habitat, to understand more of the declining salamander population.

The study was documented in the journal Global Change Biology.