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

Abstract

Understanding what species characteristics allow some alien plants to become invasive while others fail is critical to our understanding of community assembly processes. While many characteristics have been shown to predict plant invasiveness, the importance of plant–soil feedback (PSF) in invasions has been difficult to assess since individual studies include only a few species and use disparate methodology. We studied PSF of 68 invasive and non‐invasive alien species in a single two‐phase common garden experiment, and compared the relative importance of PSF, residence time, phylogenetic novelty and plant traits for plant invasiveness. Additionally, we explored relationships between PSF, residence time and phylogenetic novelty. PSF for seedling establishment, but not for biomass, was a significant predictor of invasive status, with invasive species having more positive PSF than non‐invasive species. Its explanatory power was, however, much lower than that of specific leaf area, height and residence time. 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. We demonstrated that PSF for seedling establishment plays a role in predicting plant invasiveness and is a better predictor than more commonly studied PSF for plant biomass. Other species traits, such as specific leaf area, however, predict plant invasiveness much better than the PSF.