Impact of mowing on the dominance of Erigeron annuus

Alien species often establish successfully by exploiting opportunities created by human-induced disturbances. However, the effects of disturbance may differ among plant groups with contrasting life-history strategies and depend on disturbance timing relative to species establishment. This study examined how mowing and its timing influence the establishment and dominance of Erigeron annuus and whether mowing-induced changes in plant groups with contrasting life-history strategies alter vegetation succession. Field surveys were conducted at two sites in Korea to assess the effects of mowing on relative light intensity, E. annuus establishment, and importance values across life-history groups. Mowing opened the vegetation canopy and significantly increased light availability near the soil surface. The density and coverage of E. annuus increased under mowed conditions, whereas the absence of mowing did not promote its establishment. However, mowing conducted in late September did not increase either the density or coverage of E. annuus in the following year. Mowing also increased the importance value of E. annuus , while the summed importance values of perennial species decreased. These findings suggest that repeated mowing, when it creates gaps during the establishment period of E. annuus , facilitates its persistent invasion and delays succession by suppressing perennial species. Therefore, effective management of E. annuus in human-managed landscapes requires a successional perspective that focuses not simply on removing aboveground biomass, but on minimizing gap formation during the germination and establishment period and maintaining stable coverage of perennial herbaceous communities.