Experimental AIS removals showed that (1) AIS can be controlled with nominal collateral injury and mortality of native species. Removals also (2) resulted in significant and sustained reduction of AIS densities, with the magnitude of reductions varying by target species and stream discharge. AIS removals also (3) triggered a pulse in recruitment and sustained increases in growth and body condition in A. stamineus. Though island-wide trends in A. stamineus life history (4) tracked discharge and densities of invasive Poeciliid live-bearers, AIS removals only led to a modest shift in the balance of local variation. Nonetheless, (5) genomic diversity increased following AIS removals, likely reflecting shifts in recruitment and life history. While AIS removals (6) did not elicit sweeping changes in ecosystem processes, some conditions did become more favorable for native species, like reductions in total suspended sediment (i.e., clearer water). Finally, model simulations illustrated functional trait differences can be strategically utilized to not only restore local populations but also to achieve metapopulation-wide benefits through demographic spillover.