Effects of nitrogen addition on the competition between the invasive species Flaveria bidentis and two native species

Flaveria bidentis (L.) Kuntze, an invasive plant in China, has caused serious environmental and agricultural problems. A competition experiment with and without nitrogen fertilizer under field conditions was conducted to determine the competitive ability of the invasive plant species with two native species. The results showed that fertilization only increase relative growth rate of F. bidentis in the monoculture and the photosynthetic rates of the invasive species when it competed with Abutilon theophrasti. The growth of Leonurus heterophyllus was inhibited, while the growth of A. theophrasti was promoted by competition with F. bidentis. Nitrogen fertilizer addition significantly decreased the positive effect and increased the negative effect on A. theophrasti. The higher relative growth rate and net assimilation rate might give A. theophrasti a competitive advantage in comparison to L. heterophyllus in the competition with F. bidentis due to its greater ability to utilize available resources.