Comparing insect and fish assemblage responses to urbanization for sustainable management of stream ecosystems

Invertebrates and fish are effective indicators of stream health, but individual biotic metrics may not fully capture the mechanisms of stressor impacts on streams. Insects drift downstream as larvae, but are capable of dispersing by flight across upland areas. In contrast, fish are mobile throughout their lives, but are restricted to stream channels for dispersal. These differences may have the greatest effect when attempting to identify stressors operating at the landscape scale, such as dispersal barriers. Sustaining stream ecosystem requires a complete understanding of landscape stressors influencing biotic assemblages. We investigated insect and fish assemblage responses to urbanization in streams in Massachusetts, USA. We assessed corresponding and competing responses by the insect and fish assemblages to land cover within the catchment and throughout the landscape surrounding the sample locations. Dissimilar responses of stream insect and fish assemblages to anthropogenic disturbances indicate the need for multispecies assessments to develop effective sustainable management tools.