A long-term common garden experiment reveals geocytotype-dependent succession of plant community invaded by Solidago canadensis.

Invasive alien plants can act as "drivers", actively modifying plant community succession, or as "passengers", passively persisting without significantly affecting vegetation dynamics. Canada goldenrod (Solidago canadensis) is considered a 'passenger' species, transiently dominating old-field communities in Europe, while research in Asia indicates that different geo-cytotypes of S. canadensis influence succession in a cytogeography-dependent manner, with introduced polyploids acting as drivers. However, whether these effects are temporary or long-lasting remains unclear, necessitating long-term observation. We conducted a 10-year common garden experiment to investigate the impact of different geo-cytotypes of S. canadensis on succession in old-field plant communities. Both diploid and native polyploid populations subjected to regular mowing, gradually disappeared, while herbaceous plant communities transitioned to woody communities by the fourth year. In contrast, introduced polyploid S. canadensis co-dominated alongside woody plants until the eighth year. By the tenth year, all communities, including those initially dominated by introduced polyploids, were primarily composed of woody species. While the geo-cytotype influenced the rate of succession, it did not alter its course. These findings suggest that, regardless of geo-cytotype, S. canadensis ultimately functions as a passenger in the long-term succession of invaded plant communities.