Invasive, non-native plants frequently restructure ecosystems by homogenizing vegetation and altering trophic interactions, but the ecological consequences of invader removal are less predictable. Removal can redistribute light, nutrients and detrital resources, initiating community reassembly that extends beyond vegetation recovery and may facilitate secondary invasions. We used a single-site invasive-removal field study to examine how management of European buckthorn (Rhamnus cathartica L.) reshaped vegetation structure, litter accumulation and faunal communities in a post-industrial forest preserve in western New York, USA. Across 18 plots representing managed, not-treated and regrown buckthorn conditions, we quantified herbaceous vegetation, leaf litter biomass and the abundance of arthropods, pollinators and small mammals. Rhamnus cathartica removal was associated with a tenfold increase in herbaceous plant cover and species richness, producing structurally complex understories and higher arthropod and pollinator abundance. However, managed plots also supported three- to fivefold higher densities of the invasive European fire ant (Myrmica rubra [Linnaeus, 1758]) – corresponding with increased leaf litter in managed plots. Ant abundance was positively associated with thicker, more persistent litter layers rather than canopy openness, and increasing M. rubra density, in turn, corresponded with reduced pollinator abundance. Detritivore and rodent responses were more closely linked to vegetation structure and litter conditions than to ant abundance.