Abstract: Mikania micrantha, an invasive plant species, causes significant harm in South China. Utilizing plant replacement control can mitigate the detrimental effects of invasive species and yield ecological and economic benefits. We examined the effect of species diversity and community nurturing time on resistance of five forage grass species to M. micrantha invasion, including Medicago sativa, Trifolium hybridum, Stylosanthes guianensias, Lolium perenne, and Dactylis glomerata. The results showed that when M. micrantha and forage grasses grew simultaneously, the forage grass communities had poor control over M. micrantha. When M. micrantha invaded mature forage grass communities (nearly 4 months of nurturing), an increase in forage grass diversity resulted in a decrease in M. micrantha biomass, but the difference was not statistically significant. When inoculated with soils without M. micrantha conditioning, an increase in forage grass diversity increased the individual growth of M. micrantha and forage grasses through soil legacy effect. Biomass of forage grasses was negatively related with that of M. micrantha, and this relationship was particularly strong when M. micrantha invaded mature forage grass communities, indicating that mature forage grass communities with substantial biomass could effectively suppress M. micrantha. Aboveground biomass of mature forage grass communities containing S. guianensias ranged from 75.16 to 162.2 g per pot, but that without S. guianensias ranged from 0.2 to 15.66 g per pot. Therefore, planting S. guianensias either alone or in combination with other forage grass species and nurturing these communities for a period of time (nearly 4 months) can effectively resist M. micrantha invasion.

Key words: Mikania micrantha, invasion resistance, forage grass, diversity, replacement control