Stellera chamaejasme enhances soil bacterial adaptive potential to facilitate expansion

Poisonous weeds pose severe threats to ecosystem functions and services in grasslands. Soil microorganisms play crucial roles in mediating plant growth and adaptation, yet their responses to poisonous weeds and potential contributions to plant expansion via enhanced microbial adaptability remain elusive.

Here, we carried out a large‐scale investigation spanning 3000 km across grasslands dominated by Stellera chamaejasme , an iconic poisonous weed widely distributed in China, aiming to elucidate soil bacterial community assembly mechanisms, ecological and evolutionary attributes, and co‐occurrence network traits, thereby revealing microbial environmental adaptive potential.

The results indicated that stochastic processes played a significantly greater role in shaping soil bacterial community assembly in Stellera ‐dominated grasslands than control grasslands free of Stellera . Correspondingly, bacterial communities showed broader niche breadths, stronger phylogenetic conservatism and more complex and stable co‐occurrence networks.

Synthesis and applications . Our findings demonstrate that soil bacterial communities in Stellera ‐dominated grasslands exhibit enhanced environmental adaptive potential, as indicated by proxy metrics including stochasticity, niche breadth, phylogenetic signal and network topology. This enhanced potential may be associated with Stellera colonization and expansion across heterogeneous habitats via positive plant–soil feedbacks. Therefore, disrupting this positive feedback and modulating microbial communities beneficial to palatable forage species may contribute to grassland restoration.