Human activities, propagule pressure and alien plants in the sub-Antarctic: Tests of generalities and evidence in support of management

► Invasive alien plants on islands are thought to have low impact. ► On Southern Ocean Islands, such species have rapidly increased their ranges. ► Propagule pressure, climate change and residence time are significant factors. ► Data deficiency may account for previous estimates of low impact. ► Management interventions should target potential invaders with limited current ranges.