Species diversity mediates negative impacts of plant invasion on native‐community flowering synchrony

Plant invasion is a major global driver to the structure of natural communities. Species diversity is a fundamental determinant of community regeneration through flowering phenology. However, the impacts of plant invasion on native plant flowering phenology and how species diversity regulates the process remain unclear. We conducted a field experiment to assess the effects of plant invasion (Solidago canadensis) and community species diversity on flowering phenology of native plants from different flowering functional groups at the community and species levels. At the community level, plant invasion shortened flowering duration and reduced flowering synchrony. Furthermore, high diversity reduced the negative impacts of plant invasion on flowering synchrony. Among flowering functional groups, the late- and mid-flowering species responded more negatively to plant invasion than the early-flowering species. Structural equation modeling indicated that plant invasion suppressed plant height and first or last flowering date by reducing light availability, which in turn affected flowering phenology. However, high diversity counteracted the negative effects. Our findings confirm the role of high diversity in resisting plant invasions on flowering phenology and reproduction of native plant communities, and suggest that high diversity with different flowering functional groups should be considered to efficiently restore native communities invaded by alien plants, such as S. canadensis.