East Coast vs West Coast: effects of an insecticide in communities containing different amphibian assemblages

Abstract

AbstractThe importance of understanding the mechanisms underlying insecticide disturbances in natural systems is growing because of increasing global insecticide use. Despite the prevalence of pesticides and the vulnerability of aquatic systems to insecticides, little is understood about the effect of lower concentrations of insecticides (<1 ppm) on aquatic community interactions. Whether insecticide effects are generalizable across different aquatic assemblages and trophic levels also is unclear. Furthermore, few investigators have examined the indirect consequences of insecticides beyond the primary consumer level. We examined how a single application of malathion at 3 concentrations (0, 6, or 40 µg/L) and the presence or absence of zooplankton predators (larval salamanders) affected aquatic communities composed of zooplankton, phytoplankton, periphyton, and 2 geographically distinct amphibian assemblages from Oregon and Pennsylvania. At these concentrations, malathion was directly lethal to certain zoo...