Rachel Carson Syndrom

For years some ecologists have been convinced that pesticides are contributing to a decline in amphibian species around the globe. From an apparent epidemic of deformed frogs in Minnesota to the near disappearance of yellow-legged frogs from California’s Sierra Nevada Mountains, pesticides have been considered prime suspects. This suspicion is no doubt rooted in the belief by the ecological community that the agricultural pesticide DDT was responsible for a serious decline of raptor bird populations in North America after WWII—a theory popularized by Rachel Carson’s 1962 bestselling book, Silent Spring. Over the past decade, tens of millions of dollars have been spent looking for the offending chemical or chemicals involved in the amphibian declines. Yet time after time, no evidence has been found that pesticides are involved. Four high-profile case studies show how scant the evidence against pesticides is, as well as the deep bias of the ecological research community. Mountain yellow-legged frogs began disappearing from lakes high in the Sierra Nevada decades ago. Several groups of researchers have suspected agricultural pesticides from California’s Central Valley farmland as causing the decline and conducted research on pesticide levels in frogs and the environment. Yet the culprit turned out to be the deliberate stocking of these lakes with non-native trout, starting in earnest 30 years ago. Mountain yellowlegged frog tadpoles simply get eaten by the trout. When the trout are removed from a lake, the yellow-legged frog populations rebound. Yet some researchers continue to claim that pesticides are damaging amphibian populations. Environmental activist groups have filed lawsuits in state and federal courts for inadequate testing and regulation of agricultural pesticides. In Minnesota, the finding of a bunch of deformed frogs in a farm pond in the mid-1990s eventually led to a frantic search by the Minnesota Pollution Control Agency for the guilty agricultural pesticide or chemical. Preliminary testing even led the MPCA to distribute bottled water to some families because Rachel Carson Syndrome: Jumping to Pesticide Conclusions in the Global Frog Crisis