Salamanders are Getting Smaller Due to Climate Change
Scientists have found wild salamanders in North America are getting smaller as their surroundings get warmer and drier.
The research didn't start out as a climate change-related project. Karen Lips of the University of Maryland, College Park, said she and colleagues were trying to figure out why salamander populations have been declining in recent decades.
Scientists had suspected that wildlife might change in size to better cope with the warmer, and drier conditions that climate change is bringing on.
That's when the researchers decided to compare the lengths of the specimens they collected with those of museum specimens collected from the same areas from 1957 onward.
A University of Maryland research team studied museum salamanders living in the Appalachian Mountains from 1957 to 2007 and wild salamanders measured at the same sites in 2011-2012. In total, the analysis included more than 9,000 specimens from more than a dozen species.
They found that the salamanders studied after 1980 were, on average, 8 percent smaller than those from earlier decades. The size changes were most pronounced for salamanders in the Southern Appalachians and at low elevations where settings of the climate has warmed and dried out over the years.
"Body size is a really, really important factor for most animals," said Dr Lips, explaining how this shrinking could be connected to declining numbers.
"Bigger animals in general tend to get more mates, they have more offspring, they tend to win in any sort of battles - whether it's courtship or territorial behaviours."
"When you shrink that affects what can eat you, what you can eat, how successful you're going to be at reproducing. Bigger is generally better."
"I was surprised ... The fact that we're finding some interesting results in a completely unexpected area was pretty cool," Lips says.
On average, salamanders shrunk by 1 percent per generation.
"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 and the study's senior author, said in a statement. "We don't know exactly how or why it's happening, but our data show it is clearly correlated with climate change."
The findings are published in the journal Global Change Biology.
According to the researchers, the future looks troubled for the salamander species.
"In terms of climate change, the Appalachian mountains where we're working are predicted to be impacted pretty heavily and it's a global biodiversity hotspot for salamanders."
Alongside her team of students, Dr Lips intends to continue the research to find out whether the shrinking salamanders will be able to adapt to their changing environment.