PLAIN DEALER (Cleveland, Ohio) 18 February 06 NE Ohio salamanders, wood frogs dying - Study: Toxic levels of copper in ponds (John C. Kuehner)
Lethal levels of copper in pond water appear to be killing some salamanders and wood frogs in Northeast Ohio, a 10-year study by the Cleveland Museum of Natural History has found.
A decline in salamander and wood frog populations would have a huge impact on Ohio's wildlife because they are a key link in the animal food chain -- they are eaten by larger animals and they eat smaller critters, said Tim Matson, curator of vertebrate zoology at the museum who co-authored the study.
Loss of salamanders and wood frogs at this pond could signal a more widespread problem across the region for these species, and possibly other amphibians, he said.
"This opens a lot of questions," Matson said. "If nothing else, this is going to raise the issue of metal toxicity in Northeast Ohio."
Starting in 1993, Matson and Ed Quinn, the former resource manager at Lake Metroparks, recorded the comings and goings of three species of salamanders that returned yearly to breed at a secluded woodland pond in Indian Point Park in Leroy Township.
They wanted to find out if local salamander populations were declining.
What the researchers witnessed over a decade was a dramatic drop in two species of salamander, the spotted and the Jefferson. A third species, the marble, fluctuated but stayed relatively the same.
Drought played a major role in the decline, because the pond dried up early most years and killed the young.
The third species, the marble salamander, also played a role. It has a different breeding cycle from the other two, so its young would mature first and eat the eggs and larvae of the other two salamanders.
The spotted salamander dropped in numbers at that pond from 182 to 85. The Jefferson slid from 155 to less than 20, and of those only one was a male, Matson said.
Salamanders live up to 15 years. They have adapted to boom and bust population cycles, and survive droughts.
But it was not until Matson started sampling the water chemistry the last year of the study, and the following year, that he found unusually high levels of copper, which can be toxic to some salamanders.
He found similar high levels in three ponds at the Mentor Marsh, where the museum began to re-introduce hundreds of thousands of wood frog eggs in 2002.
Juvenile frogs were present the first two years, but by last June, researchers found no frogs or tadpoles, he said.
The copper may occur naturally in the soil, or it could be from air pollution, or carried by surface water from agricultural or yard weed-control practices.
The study, which ended three years ago, has raised more questions about heavy metals in ponds.
Matson plans to take water samples at 30 ponds in Lake, Geauga and Ashtabula counties this year.
"I hope to answer some questions and stimulate some additional follow-up studies," he said. "This might be a reason why people are not hearing wood frogs any more."
NE Ohio salamanders, wood frogs dying