Soil legacy effect of extreme precipitation on a tropical invader in different land use types

Land use change and extreme precipitation are the main challenges for tropical forests, and numerous studies have indicated that these changes could affect soil ecology. However, it is not yet known whether the soil legacy effect of ongoing changes could influence the invasiveness of alien plants. Two mixtures of invader and native species (Chromolaena odorata-Artemisia leucophylla and C. odorata-Desmodium sequax) were transplanted to 18 soil treatments (3 forest types x 3 pre-water supply levels x 2 microorganism treatments). The results showed that the biomass of the invader was greater while its biomass fraction was lower in secondary forest soil than in primary and rubber forest soil; the soil legacy effect of drought was positive on both the biomass and biomass fraction of C. odorata. In rubber plantation soil, the biomass and biomass fraction of C. odorata were enhanced by the pre-increased water supply level. In primary and rubber forests, compared with normal precipitation, the sterilization treatment increased the biomass of the invader under drought and increased precipitation. The nutrient cycle and microorganisms both played a crucial role in this process. Overall, our study demonstrated the pronounced soil legacy effect of land use change, extreme precipitation and their interactions on the invasion success of C. odorata.