Decoupling the dimensions of plant invasion success reveals divergent trait syndromes across invasion outcomes and growth forms

Gabriela Nunez-Mir , Bethany Bradley, Qinfeng Guo

The number of invasive plant species and their impacts continue to increase globally, yet efforts to identify traits that reliably predict invasion success have produced inconsistent results. To address this challenge, we asked whether trait–invasion relationships vary across dimensions of invasion success and growth forms. Using 16 functional and niche traits for 622 invasive plant species across the continental United States, we tested the effects of traits on three dimensions of success: local abundance, habitat breadth, and invasive range size. Native range size and tolerance of stressful environments consistently predicted habitat breadth and invasive range size across growth forms. In contrast, the traits associated with local abundance differed markedly between woody and herbaceous invaders. Herbaceous species were associated with traits linked to competitive dominance, whereas woody species were associated with persistence, stress tolerance, and competitive tolerance. These findings reveal multiple pathways to invasion success and show that invasion dimension and growth form are critical considerations when predicting plant invasiveness.