There is a debate whether invasive plants can induce extinction debt in native flora that is not immediately obvious. Competitive effects of invasions and how competition causes native biodiversity loss are complicated to evaluate. Experi-mental removal or introduction bears the most promise of demonstrating native species displacement mechanics. Over an eight- year period, we followed plots in the only remaining Scalesia pedunculata forest on Santa Cruz Island, Galapagos, where invading Rubus niveus was either removed or retained. Demographic param-eters and total recruitment failure in the presence of R. niveus suggest that S. pedun-culata may face local extinction in two decades without invasion management.