Plant-soil feedback contributes to predicting plant invasiveness of 68 alien plant species differing in invasive status

1. Understanding what species characteristics allow some alien plants to become invasive while others fail to is critical to our understanding of community assembly processes. While many characteristics have been shown to predict plant invasiveness, the importance of plant-soil feedbacks (PSFs) in invasions has been difficult to assess since individual studies include only a few species and use disparate methodology.\n\n2. We studied PSFs of 68 invasive and non-invasive alien species in a single two-phase garden experiment, and compared the relative importance of PSF, residence time, phylogenetic novelty and plant traits for plant invasiveness. Additionally, we tested for relationships between PSF, residence time and phylogenetic novelty.\n\n3. PSF for seedling establishment belonged to five best predictors of plant invasiveness, along with specific leaf area, height, seedling growth rate, and residence time. Invasive species had more positive PSF for seedling establishment, but not for biomass, than non-invasive species. Phylogenetically novel species experienced less negative PSF than species with native congeners, suggesting they benefit more from enemy release. PSF of non-invasive species, contrary to that of invasive species, was becoming more negative with increasing residence time.\n\n4. Synthesis. We demonstrated that PSF plays a role in predicting invasiveness that is comparable with other species characteristics that are more commonly studied. PSF should thus receive more attention in studies predicting community structure and in programs assessing the likely invasions of aliens.