| contaminant residues and declines of the cascades frog (rana cascadae) in the california cascades, usa. | populations of cascades frogs (rana cascadae) have declined precipitously in the mount lassen area, but remain abundant in the other half of their california range in the klamath mountains. to evaluate the role of contaminants in cascade frog declines, we sampled sediment and frog tadpole tissue at 31 sites where cascades frogs had disappeared and sites where cascades frogs are still present across the lassen and klamath regions. pacific chorus frogs (pseudacris regilla) were tested and used as ... | 2012 | 22639410 |