Species traits, as opposed to traditional taxonomic measures of community composition, reduce complexity and provide a community framework that can be applied to any ecosystem. Because of these advantages, trait-based analysis has been proposed as a more general approach to testing ecological theory. For example, the Habitat Templet Hypothesis predicts that the environment filters species according to their traits, thus leading to the prediction that the species’ abundance along an environmental gradient should correspond to the species’ trait composition. The objective of this study was to explore 1) the correlation between functional traits of aquatic insects along environmental gradients in streams (e.g. disturbance frequency, substrate size), 2) whether individual species carrying the same trait respond similarly along the same environmental gradients, and 3) whether considering multiple traits simultaneously provides further insight into species’ responses. The relative abundances of over 100 taxa and 20 traits from over 200 EPA EMAP sites in the western United States were used in a regression analysis to examine these questions. Results indicate that traits can provide a mechanistic understanding of the distribution and abundance of species along environmental gradients, but individual species responses and trait tradeoffs can mask this influence.