Impact of global warming questioned

STATE COLLEGE, Pa., Nov. 12 (UPI) -- A U.S. scientist says evidence that global warming is causing a worldwide decline of amphibians might not be as conclusive as previously thought.

Penn State Professor Peter Hudson, co-author of the study, said the massive declines in amphibians around the globe seem to be linked with the chytrid fungus.

Hudson said there are currently two theories on the extinctions. The first suggests the declines were triggered by global warming, which has pushed temperatures to levels optimal for the growth of the chytrid fungus. The second theory posits amphibian declines are simply driven by the introduction and subsequent spread of the fungus from certain locations.

Hudson says his study suggests both theories are slightly wrong, since neither fit available data.

"We are facing a cataclysmic global decline in amphibians, caused primarily by the effect of a fungus that was historically not important, but the emergence of which might be associated with climate change, along with the use of herbicides and pesticides," said Hudson. "The bottom line is that there doesn't seem to be one single explanation for the massive amphibian declines. It could be a mix of other factors."

The research also included Assistant Professor Jason Rohr, Assistant Professor Thomas Raffel and John Romansic, all from the University of South Florida, and Professor Hamish McCallum at the University of Tasmania.

The study was reported in a recent issue of the Proceedings of the National Academy of Sciences.