Decline in frog populations: Encyclopedia II - Decline in frog populations - Pollution

Decline in frog populations - Pollution

Pollutants are causing frog deformities such as multiple limbs, stunted growth or misplaced eyes. Researcher and naturalist Gary Fellers has been tracking the deformation and decline of the frog population in Yosemite National Park in California. He attributed these occurrences directly to "pesticides wafting over the Sierra Nevada mountains from...farms in California's Central Valley". ("What's Killing the Frogs?” Newsweek May 13, 2003, pg 46).

Pollutants have varying effects on frogs. Some alter the central nervous system; others like atrazine cause a disruption in the production and secretion of hormones (UC Berkeley biologist Tyrone Hayes).

Recent evidence points to ozone as a possible contributing factor to the worldwide decline of amphibians (Dohm, M.R., et al. 2005. "Effects of ozone exposure on nonspecific phagocytic capacity of pulmonary macrophages from an amphibian, Bufo marinus." Environmental Toxicology and Chemistry 24 (January):205–210).

A 2004 study by researcher Rick Relyea at the University of Pittsburgh found that populations of tadpoles declined greatly when exposed to the commonly used herbicide Roundup as well as the insecticides malathion and carbaryl. Another study in 2005 by the same researcher found that Roundup was also lethal to terrestrial frogs and toads. Specifically implicated is the surfactant POEA, a component of Roundup which is not itself a pesticide.

Adapted from the Wikipedia article "Pollution", under the G.N U Free Docmentation License. Please also see http://en.wikipedia.org/wiki