Water shrews are semi-aquatic insectivores of clean UK streams and ponds, increasingly threatened by agricultural pesticide runoff that reduces invertebrate prey and directly causes sublethal toxic effects.
Water shrews have high metabolic rates and must eat frequently; prey declines cause rapid starvation stress. Sublethal pesticide exposure may impair hunting ability and neurological function. The combination of reduced prey availability and potential direct toxicity from pesticide-contaminated water makes agricultural intensification a multi-pathway welfare threat to this species.