Asymmetric inter-specific competition between invasive Phytolacca americana and its native congener

Interspecific competition is an essential factor affecting the invasiveness of alien plants. Phytolacca americana , one of the most destructive invasive plants in China, was introduced from North America into China in 1935. Its population expand, thereby causing the loss of the ecological niches of its native congener and a shrinking of Phytolacca acinosa population. In this study, we used the invasive plant P. americana and its native congener P. acinosa to assess their competitive interaction in response to different competition patterns and spray treatments in a pot experiment in a homogeneous garden at Yunnan University. The results indicate that an asymmetric competition occurred between P. americana and P. acinosa in inter-specific competition. Specifically, P. americana severely inhibits the growth and reproduction of P. acinosa , and it was superior to P. acinosa in terms of defense strategy on account of its stronger resistance against insects and bacteria. Our study provides some theoretical basis for assessing the invasive plant P. americana .