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.
uvenile 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.
EDIT
http://www.cleveland.com/enter/index.ssf?/news/plaindealer/index.ssf%3f/base/cuyahoga/114025585369310.xml&coll=2&thispage=2