Clonal functional traits favor the invasive success of alien plants into native communities

Functional traits are frequently proposed to determine the invasiveness of alien species. However, few empirical studies have directly manipulated functional traits and tested their importance in the invasion success of alien species into native plant communities, particularly under global change. We manipulated clonal integration (a key clonal functional trait) of four alien clonal plants by severing inter-ramet connections or keeping them intact and simulated their invasion into native plant communities with two levels of species diversity, population density and nutrient availability. High community diversity and density impeded the invasion success of the alien clonal plants. Clonal integration of the alien plants promoted their invasion success, particularly in the low-density communities associated with low species diversity or nutrient addition, which resulted in a negative correlation between the performance of alien plants and native communities, as expected under global change. Thus, clonal integration can favor the invasion success of alien clonal plants into degraded resident communities with a high degree of disturbance and eutrophication. Our findings confirm the role of clonal functional traits in facilitating alien plant invasions into native plant communities and suggest that clonal functional traits should be considered to efficiently restore degraded communities heavily invaded by alien clonal plants.摘要 功能性状常常被认为是决定外来物种入侵性的关键因素。然而，迄今很少有实证研究直接操控功能性状来检验其在外来物种成功入侵本地植物群落中的重要性，尤其是在全球变化的背景下。克隆整合是克隆植物最重要的功能性状之一。通过切断或不切断分株之间的连接，我们操控了4种外来入侵克隆植物的克隆整合，并模拟它们入侵两种不同物种多样性水平、两种不同密度和两种不同养分可用性的本地植物群落。高群落物种多样性和高群落密度阻碍了外来克隆植物的成功入侵。外来入侵植物的克隆整合可以显著促进其对本地植物群落的成功入侵，这种效应在物种多样性低或具有高养分水平的低密度群落中尤为明显，并导致外来植物与本地群落生长之间呈显著的负相关。因此，克隆整合有助于外来克隆植物成功入侵遭受高度干扰和富营养化的退化本地群落。本项研究成果证实了克隆功能性状在促进外来植物入侵本地植物群落中的作用，表明为有效恢复被外来克隆植物严重入侵的退化群落，我们应考虑外来入侵物种克隆功能性状。.