Alien and Invasive Plants in Context: Disturbance, Facilitation, and Conservation Trade-Offs

Non-native plants differ widely in their ecological effects, yet this variation does not diminish the harm caused by damaging invasions. This narrative review examines three related questions: how prior disturbance and subsequent plant impacts can be distinguished; when non-native plantations can facilitate native forest recovery; and how conservation objectives, socioeconomic drivers, and management costs should inform intervention. A thematic selection of assessments, syntheses, and case studies is interpreted alongside contemporary global assessments. Disturbance can create opportunities for establishment, after which non-native populations may reinforce degradation through changes in fire, soil, hydrology, and species interactions. Existing plantations can sometimes support native recruitment on degraded forest land, but recruitment alone does not demonstrate restoration success. Benefits must be assessed against invasion risk, effects on other components of biodiversity, and the feasibility of the transition to native vegetation. Likewise, conservation concern in a species’ native range does not remove the need to manage harmful populations elsewhere. The synthesis links these established findings to a population-level decision sequence that separates biogeographic origin, invasion stage, causal evidence, ecological impact, and management feasibility. Its purpose is to improve the interpretation and application of invasion evidence, without estimating the global frequency of beneficial or harmful outcomes.