Multiple biotic factors mediate the invasion success of Chromolaena odorata

Community resistance plays a crucial role in the successful invasion of alien plants. However, our understanding of how the soil legacy effects of native species richness, parasitic plants, competition and soil microbes contribute to shaping community resistance has not been achieved. In this study, we grewChromolaena odorataand two co-occurring native plants from three soil sources (native richness gradient, i.e., heavily invaded moderately invaded and lightly invaded). We then implemented treatments containing parasitism (Cuscuta chinensis), competition and sterilization. Overall, our research indicated thatC. odorataoutperformed two other native species (in terms of height and biomass). However, our findings also revealed that both the soil legacy effects of native plant richness and competition negatively impact the growth ofC. odorata, and native plants tend to produce more biomass in soils with greater diversity and under competitive conditions (5.0%). Interestingly,C. chinensisparasitism had asymmetric negative effects on alien (-11.1%) and native plants (-39.9%). Furthermore,C. odoratadid not experience limitations from parasitism in sterilized soil, as indicated by a slight increase in biomass of 2.3%. This study underscores that community resistance toC. odoratais governed by an interplay of multiple biotic factors, both individually and in combination.