Conclusion
Our study demonstrated that the resistance from both native plants and co-occurring exotic plants was the most important factor determining plant invasion in freshwater ecosystems. It implied that biodiversity conservation and native vegetation restoration are essential to control plant invasion. If no native vegetation fills the blank niches left by the removal of invasive plants through enemies or mechanical control, invasive plants will return or be replaced by other invasive plants. And it also suggested that managing and modeling the invasive species must take into account the interactions between invaders which have always been ignored (Kuebbing et al. 2013). In addition, we found that the effects of some factors on different exotic aquatic plants were varied as well as the relative importance and modes of their effects, more studies involving multiple approaches and multiple invasive species are required to address the invasion patterns in freshwater ecosystems (Thomaz et al. 2015).