We investigated preferential insect colonization of natural versus artificial leaves in forested streams to determine the impact of invertebrate-substrate associations on macroinvertebrate community composition and ecosystem nutrient cycling. We created 10 onion bags filled with natural maple leaves and 10 filled with artificial maple leaves, and placed 5 of each in two forested streams, one larger and one smaller, in the Sebago Lake Land Reserve in Standish, Maine. We identified the aquatic macroinvertebrates found on these samples after approximately one month to order-level and used Maine DEP biomonitoring data and functional feeding group taxonomies to classify macroinvertebrates by functional feeding groups. There was a greater difference in Simpson diversity values between habitats than between substrate types and a substantially greater difference in functional feeding group composition between habitats than between substrate types. The patterns in functional feeding group abundance across habitats (specifically the decline in shredder proportions from the smaller stream to the larger stream) match the patterns of the river continuum concept. This indicates an unexpectedly high degree of small-scale ecosystem heterogeneity, with wide potential implications for ecosystem-level macroinvertebrate community structure and nutrient cycling
