Exploring the Novel Weapons Hypothesis with invasive plant species in China

The Novel Weapons Hypothesis (NWH) proposes that some invasive plant species gain advantages over native plants by possessing the novel allelopathic, defence, or antimicrobial chemicals. There is evidence for the NWH from geographical comparisons, chemical isolation and bioassays, but there are few studies to compare the potential allelopathic effects of numerous species in a specific region. We explored the NWH by evaluating the allelopathic potential of most noxious invasive plants in China. We found evidence for allelopathic effects for 25, of the 33 most noxious invasive plants in China. In particular, invasiveness in the Asteraceae appeared to rely on allelopathy. Our results indicate that invasive plants species have substantial allelopathic potential, to support the NWH, but not all strong invaders demonstrated the allelopathic potential.