Amphipods (Gammarus pseudolimnaeus) prefer but are harmed by a diet of non-native leaves

The strong dependence of headwater streams on allochthonous inputs of energy and nutrients from riparian plant communities predicts that the introduction of non-native tree species should significantly affect these stream systems. The response of macroinvertebrate shredders to native and non-native leaves entering the stream will affect the transfer of energy and nutrients to other components of the ecosystem, but the specifics of such a response appear to be highly variable across systems. We investigated whether a locally abundant shredder, the amphipod Gammarus pseudolimnaeus, preferred stream-conditioned native (green ash, Fraxinus pennsylvanica) or non-native (common buckthorn, Rhamnus cathartica) leaves and how an exclusive diet of conditioned leaves of each species influenced amphipod survival, body mass, behavior, and energetics in a laboratory setting. Amphipods significantly preferred leaves of common buckthorn to those of ash. However, a 24-d diet of buckthorn leaves resulted in signifi...