Effects of Toxic Weeds Invasion and Expansion on Subalpine Meadow Plant Communities and Soil Properties

Purpose To study the effects of toxic weeds invasion and expansion on alpine meadow plant communities and soil properties.

Methods Taking the national subalpine meadow fixed monitoring plot in Shangri-La City, northwest Yunnan as the research object, and the three patches within the plot, Poa pratensis, Euphorbia jolkinii and Ligularia dictyoneura, as the sampling units, the plant community composition and structure, soil chemical properties, soil enzyme activity and microbial biomass of the meadow invaded and expanded by toxic weeds were analyzed.

Result The invasion and expansion of E. jolkinii and L. dictyoneura led to a significant decrease in vegetation density and the biomass of excellent forages, while the biomass and proportion of toxic weeds significantly increased. Furthermore, the invasion significantly increased the number of soil bacteria, fungi, and actinomycetes, and enhanced the contents of soil organic carbon, total nitrogen, available nitrogen, as well as microbial biomass carbon, nitrogen, and phosphorus. It also increased the activities of soil sucrase and catalase.

Conclusion The expansion of E. jolkinii and L. dictyoneura alters the vegetation and soil environment of the invaded area, creating conditions favorable for their growth, thereby promoting their spread in the subalpine meadows of northwest Yunnan.