Abstract: Mycorrhizal symbioses are critical for plant population and community dynamics, yet their role in mediating plant geographic spread under increasing anthropogenic pressure remains poorly understood. Here, we compiled geographic distribution and mycorrhizal information for 8,791 vascular plant species across China, and investigated how plant mycorrhizal strategies interact with human footprint to shape the extent to which species fill their potential ranges across species and space. We found that anthropogenic activities significantly affected range filling of arbuscular mycorrhizal plants, disproportionately reducing range filling of narrow-ranged species while benefiting widespread species. Conversely, range filling of ectomycorrhizal plants was primarily associated with abiotic environments. Our results suggest that mycorrhizal symbioses play a critical role in mediating plant responses to anthropogenic pressures across broad geographic scales and highlight the need to integrate plant-mycorrhizal interactions to predict biodiversity shifts in a changing environment.

Key words: plant-microbe interactions, mycorrhizal association, plant geographic distribution, range filling, human activity, China