Amphibians as environmental omens disputed

VERMILLION, S.D., Nov. 17 (UPI) -- A coalition of scientists from three U.S. universities is questioning the theory that amphibians are a leading indicator of environmental degradation.

Researchers from Yale University, the University of South Dakota and Washington State University said they reviewed more than 28,000 toxicological tests before challenging the prevailing view that amphibians, with their permeable skin and aquatic environment, are particularly sensitive to environmental threats.

"The very simple message is that for most of the classes of chemical compounds we looked at, frogs range from being moderately susceptible to being bullet-proof," said Yale Professor David Skelly, a member of the research team. "There are lots of other kinds of environmental threats that have led to their decline, including habitat conversion, harvesting for food and the global spread of the Chytrid fungus, which is mowing down these species in its path."

The team, led by University of South Dakota Assistant Professor Jacob Kerby, said it based its analysis on information gleaned from the Environmental Protection Agency's Aquatic Toxicity Information Retrieval database, examining 1,279 species, among them segmented worms, fish, bivalves such as clams, insects and snails.

"What our results suggest is that all animals are susceptible to chemical stressors and that amphibians are potentially good indicators," said Kerby. But, he added, "There isn't any evidence that they're a uniquely leading indicator."

The research is to appear in the journal Ecology Letters.