Research progress on Merremia boisiana
Recent researches demonstrated that Merremia boisiana is a photophilous heliophyte liana rather than a sciophyte, which has a wide ecological adaptability and contains the allelochemicals, one of invasion mechanisms of invasive species. In China, M. boisiana had a distribution in Yunnan, Guangxi, and Guangdong Provinces, but its distribution in Fujian Province has not been confirmed. Guangzhou City and its vicinity are becoming a new distribution area of M. boisiana due to its northward invasion from Hainan under global warming. However, M. boisiana is not really a kind of tropical plants, but one of the tropical and subtropical elements. The tropic of cancer is the north boundary of M. boisiana distribution, and thereby, there is a high possibility that M. boisiana is a latent local species activated by global warming. M. boisiana causes widespread disaster in its holotype locality ( Vietnam ) and its original distribution center (Hainan Province) , which is not consistent with the existing viewpoint that the invasive species cannot spread to be a disaster owing to the natural enemies in origin, while suggests that there are no fatal natural enemies in the origin. The widely spreading to be a disaster is originated from the intrinsic ecosystem being destroyed by disturbances, which causes the worsened, broken, and heterogeneous habitat. The reduced community biodiversity and functional group diversity intensify the invasive possibility of exotic communities and provide chance for invasive species. Therefore , the viewpoint that the invasion of M. boisiana is non-selective should be modified, and the prevention measures of M. boisiana remain to be break through. Integrative control should be the first choice. Additionally, protecting the natural ecosystem from disturbance, and reconstructing and optimizing the destroyed ecosystem would be the necessary strategies and measures.