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Exotic invasion of non-native fishes threatens freshwater biodiversity worldwide. Yet,

detailed estimates of population demography for invasive species, that integrate

estimates of population size and body size of the invasive species, are rarely

integrated in evaluating aquatic community responses. Our study capitalized on

detailed brook trout population demographic data collected for a replicated whole lakes

ecosystem experiment involving experimental harvesting of exotic brook trout in nine

mountain lakes. We applied morphological taxonomy and environmental DNA (eDNA)

metabarcoding to examine the response of crustacean zooplankton and

macroinvertebrate communities to gradients in brook trout effective density and lake

elevation. Density-dependent effects of brook trout on crustacean zooplankton and

macroinvertebrate communities were detected even decades after their first

introductions (between 1926 and 1980). However, they were moderated by

environmental factors such as elevation, lake maximum depth and dissolved organic

carbon. Elevation was important in structuring crustacean zooplankton and

macroinvertebrate community composition. While there were differences in explanatory

variables when describing communities characterized by morphological enumeration and eDNA metabarcoding, the principal driving environmental factors structuring the

communities were similar. Our paper highlights persisting impacts of exotic trout on

invertebrate communities even decades after first introduction.