Dynamic impact of alien plant invasion on plant diversity: a global meta-analysis

Invasive alien plants not only alter the structure and functioning of ecosystems but can also pose serious threats to native biodiversity. Understanding vegetation dynamics and succession across temporal gradients remains a central issue in plant ecology, yet the long-term effects of plant invasions on biodiversity lack a clear consensus. In this study, we conducted a global meta-analysis of 635 data sets drawn from 79 peer-reviewed publications to quantitatively assess the temporal impacts of invasive alien plants on plant diversity. Overall, invasions significantly reduced local plant diversity by 22.57% (P<0.05) and exhibited a gradual downward trend with increasing invasion duration. External disturbances showed a partial restorative effect: compared with invaded plots, disturbed plots had on average 13.71% higher diversity (P<0.05), but their diversity remained 11.07% lower than that of uninvaded plots (P<0.05). Differences among groups across varying invasion stages were relatively small, suggesting that invasion duration exerted only a minor influence on changes in diversity. Subgroup analyses further revealed that climatic zone, habitat type, and disturbance type are key moderators of invasion impacts on diversity, with their effects being more pronounced under disturbance conditions. These findings underscore the need to integrate climatic context, disturbance regimes, and habitat characteristics when predicting and managing plant invasions, and they provide quantitative evidence to inform ecological risk assessments and targeted management strategies for invasive alien plants worldwide.