Researchers study impact of warming on salamanders
Researchers in Penn State’s College of Agricultural Sciences are spearheading a four-year-old collaborative effort to assess the impact of a warming climate on the Eastern red-backed salamander, a creature that lives on or under the forest floor.
Because these salamanders do not have lungs, breath through their skin and must live in damp places, they are extremely sensitive to changes in temperature and moisture, according to David Munoz, doctoral degree candidate in ecology who helped create the Salamander Population Adaptation Research Collaboration Network (SPARCnet).
Woodland salamanders, which are found throughout most areas of North America, are the most abundant vertebrate group in Eastern temperate forests, and they are imperiled by forestry practices, land use, pollution and warming.
“Although they are often overlooked organisms, we view these salamanders as the canary in the coal mine related to climate change in the Northeast,” Munoz said.
“They are particularly sensitive to thermal changes, so we’re using them as a model species to understand how warming conditions will affect organisms in the future. Scientists are becoming increasingly confident about how the climate will change, but we don’t know how wildlife will respond.”
With 30 salamander-monitoring sites in 12 states, SPARCnet is a partnership between universities and the U.S. Geological Survey’s Patuxent Wildlife Research Center and its Northeast Amphibian Research and Monitoring Initiative.
Salamander-monitoring sites stretch from New Hampshire in the north to Virginia in the south and as far west as Michigan. To attract red-backed salamanders, each site consists of dozens of untreated, rough-hewn, wooden squares in forested plots that create spaces cooler than the surrounding forest floor litter.
Researchers are employing the traditional wildlife science mark-and-recapture method to determine salamander abundance across SPARCnet, marking the amphibians with a permanent visual implant. A technique originally devised to study fish, it involves injecting a fluorescent dye or elastomer under the skin of salamanders.
“It’s like a tattoo, and once it is injected, it hardens into a tiny plastic bead,” said Munoz. “We have a system with each salamander getting a different color in different places on its body, so using the color-location combination, each individual is unique in our data. That allows us, over time, to accurately estimate salamander survival and abundance.”