Variation in reproductive characteristics of Eupatorium adenophorum populations in different habitats

The invasive plant, Eupatorium adenophorum, produces large numbers of small seeds with a high germination rate. However, this investigation showed that E. adenophorum populations in an evergreen broad‐leaved forest had a high proportion of seedlings when compared with clonal plants. Whereas an opposite pattern was found in a deciduous broad‐leaved forest and in a roadside site. A seed addition experiment where E. adenophorum seeds were added to each of the three habitats did not increase the number of E. adenophorum seedlings at any of the three field sites. Field and greenhouse experiments demonstrated that a soil litter layer significantly reduced the number of E. adenophorum seedlings during the early seedling emergence period. However, at later periods, the litter cover did not affect survival and growth of individuals. The emergence of E. adenophorum seedlings was significantly increased in field experiments when there was no litter, and parental plants were removed. Finally, the growth of seedlings was significantly reduced when planted with their parental plants in a root box experiment. In the low‐resource environment of the evergreen broad‐leaved forest, E. adenophorum reproduced primarily by its abundant seed production. In the more open deciduous broad‐leaved forest and roadside site, the populations reproduce primarily by vegetative clones that can grow quickly, are better competitors and could take advantage of the high‐resource environment.