Effects of invasive plant Datura stramonium on the functional traits of native plants and the stoichiometric characteristics of soil carbon, nitrogen and phosphorus.
The experiment was conducted to explore effects of invasive plants under the different pressures of invasion on the functional traits of native plants and the stoichiometric characteristics of soil carbon, nitrogen and phosphorus. We used invasive plant Datura stramonium and coexisting native plants as the research object, researches species, number and height of plants in sample plots and the species diversity of native plant communities with no invasion, low invasion and heavy invasion(according to the proportion of invasive plants coverage), and analyzed the specific leaf area, carbon content, nitrogen content, carbon to nitrogen ratio, leaf construction cost and carbon, nitrogen and phosphorus stoichiometric characteristics in different soil layers. With the increase of invasion pressure, the species richness and the number of native plants decreased gradually. The plant height and leaf nitrogen content of D.stramonium were significantly higher than that of native plants under different invasion pressures, and gradually increased with the increase of invasion pressure. The carbon to nitrogen ratio was significantly lower than that of native plants in sample plots with no invasion. The specific leaf area, carbon content and leaf construction cost were not significantly different from those of native plants in sample plots with invasion. With the increase of invasion pressure, soil total nitrogen content, total carbon content, nitrogen to phosphorus ratio and carbon to phosphorus ratio increased significantly, while total phosphorus content and carbon to nitrogen ratio decreased significantly. Soil carbon and nitrogen stoichiometric characteristics show a certain surface clustering effect. These results show that D.stramonium has a high resource capture ability, and has changed the characteristics of soil, so as to enhance its own competitiveness to improve the invasion ability, which may be one of the reasons for the successful invasion of D.stramonium.