Abstract: Managing invasions in the context of globalization is a challenge in part because of the difficulty of inferring invader impacts from their invasiveness (i.e. ability to invade ecosystems). Specifically, the relationship between invasiveness and impact may be context-dependent and it has not been explored in such a unique ecosystem as the Tibetan Plateau. Here, we investigated 32 invasive plant species on the Tibetan Plateau in terms of their distribution, abundance, per capita effects on natives and traits across a large geographic transect to test the relationship between invasiveness and impacts on native communities. We decomposed the components (range, R; local abundance, A; per capita effect, E) that drive the impacts, and investigated the relative contributions of plant traits to these components. The results showed that there was no correlation between invasiveness (R × A) and impacts (R × A × E) of invasive species on the Tibetan Plateau. Specifically, plant invasiveness per se did not indicate a serious threat of harmful impact. In this ecosystem, R and A together drove invasiveness, while R alone drove impacts. Fruit type significantly influenced E, and species bearing berry fruits had the most negative per capita effects. However, plant traits did not drive invasiveness or impact through R, A or E. Our results suggest that the mismatch between components driving invasiveness vs. impact prevent the prediction of impacts of invasive species from their invasiveness. Therefore, management actions directed against invasive plants should prioritize broadly distributed species or those with demonstrated high impacts on native species.

Key words: biological invasion, biogeography, ecological impact, invasiveness, managing invasions, per capita effect, Tibetan Plateau