Green tree frogs are moving north into the Piedmont, and scientists said it’s possible that warming temperatures in the state could be the cause.
The frogs, native to the Carolinas coast and far southern tip of the Piedmont, have “expanded their range dramatically,” said Michael Dorcas, director of the Davidson College Herpetology Laboratory and a recognized expert on frogs.
“If you live by a pond or stream or you have a retention pond in your neighborhood, there’s a good chance if you’re in Charlotte you have green tree frogs around, and you didn’t 10 years ago.”
Biologists are recording green tree frogs, Hyla cinerea, “at every site where we study amphibians,” Dorcas said, and each year the numbers rise. “It’s possible climate change may allow them to persist in areas where they couldn’t persist before,” he said. “What effect is this going to have on native species that have been in the Piedmont all along? Will they displace some of the native species?”
Melissa Pilgrim is the Upstate regional coordinator for the North American Amphibian Monitoring Program and a biology professor at USC Upstate. Amphibian records going back to 1980, she said, “don’t show green tree frogs anywhere near Spartanburg County, which is the county I’m in.”
“We’ve documented green tree frogs and squirrel tree frogs as well as barking tree frogs in our area and they’re all new,” Pilgrim said. “Historically in our area there would have been (just) Cope’s gray tree frogs.”
Tree frogs hitch rides regularly on vehicles and landscaping plants. The real question is how are they able to survive and form breeding populations in cooler areas. “I tend to think it’s something going with temperature, rainfall or something going on with landscape alterations,” Pilgrim said. Pilgrim and Dorcas expect to study the advance of the green tree frog and its effect on native species.
The frogs are just one of many species shifting territories. Two dozen fish species, including herring and shad, have moved northward up the Atlantic coast or two deeper, cooler water in recent decades, Charlotte Observer writer Bruce Henderson has reported. To view other plants and animals spreading into new territory, see The Observer’s interactive graphic, here.
Green tree frogs start making their calls in April and are nearly finished singing now. To hear the call of the green tree frog, go to the Davidson Herpetology Lab.
Have you seen green tree frogs on your property? Contact us. -Amber Veverka