The expansion of native poisonous plant patches enhances soil microbial diversity in alpine meadows of the Qinghai-Tibet Plateau by mediating soil resource heterogeneity

Background Grassland patchiness degradation poses an escalating threat to grassland ecosystem functions and biodiversity, particularly in alpine ecosystems. The patches of native poisonous plants are rapidly expanding on the Qinghai-Tibet Plateau, forming degraded grasslands dominated by poisonous plants, leading to the loss of grassland ecological functions. However, the impact of Ligularia virgaurea patches expansion on soil microbial communities and the key driving factors remain unclear. In response to this concern, we analyzed the soil physicochemical properties and soil microbial communities within L . virgaurea patches of different densities and explored the impacts of L . virgaurea invasion and patches expansion on soil nutrients, enzyme activities, and soil microbial communities. Results The results of this study indicated that the expansion of L . virgaurea patches enriched more available resources within the patches. Specifically, the soil organic carbon (SOC) content increased by 4.3%, soil total nitrogen (TN) by 9.5%, and soil total phosphorus (TP) by 11.3% within the patches. L . virgaurea patches enhanced soil resource heterogeneity, indirectly affecting the abundance and diversity of soil microorganisms. The expansion of L . virgaurea patches promoted the diversity of soil microbial communities. Furthermore, we identified pH, NO ₃ ⁻ -N, and cellulase as common drivers of bacterial and fungal community changes. Conclusion Overall, L . virgaurea patches enhance the soil resources heterogeneity, changing the composition of soil microbial communities within the patches and increasing soil microbial diversity by regulating the availability of soil resources. This study clarifies the changing characteristics and interrelationships of abiotic and biological soil properties during the expansion of native poisonous plants in alpine meadows, providing a theoretical foundation for the management of grasslands affected by poisonous plants.