Pollution

A wide range of environmental contaminants (e.g. road salt, fertilizers, dioxin, PCB, pesticides and herbicides) pose threats to reptiles and amphibians. With the latter group, life cycles that straddle both aquatic and terrestrial habitats make them particularly vulnerable. For instance, in the late 1990s, a Canadian study conducted in Quebec was the first to link physical deformities and genetic damage in frogs to pesticide use in agricultural settings; during snowmelt and spring rains, the influx of field-applied substances into surrounding aquatic habitats used by breeding amphibians results in “toxic shock” to eggs and larvae. As we now know, such stressors have both acute and chronic effects that can also make amphibians more vulnerable to parasites and opportunistic diseases such as chytrid fungus and ranaviruses.