Divergent Responses of Fungal Communities to Vegetation Structural Complexity in Degraded Roadside Slopes Across Climatic Gradients

Understanding how climate and vegetation structural complexity jointly shape fungal communities is essential for effective roadside slope restoration. To address this, we examined restoration effects on fungal diversity, community composition, and ecological networks across three climatically distinct regions: dry‐hot valley, subalpine, and subtropical. In climatically stressful regions (i.e., dry‐hot valley and subalpine), plots with complex vegetation (Herb+Shrub, Herb+Shrub+Tree, and natural sites) harbored higher fungal diversity than herbaceous‐only plots. In contrast, subtropical herbaceous plots supported higher fungal diversity, likely due to disturbance‐induced niche heterogeneity. Fungal community composition differed significantly among climatic regions and vegetation types. Ascomycota was consistently dominant across all sites, whereas Mortierellomycota, Basidiomycota, and Rozellomycota exhibited distinct regional distributions. Network analyses revealed larger and more highly connected fungal networks in the subtropical and subalpine regions than in the dry‐hot valley, with topological keystone taxa identified only in the former two regions. Piecewise structural equation modeling further indicated that climate influenced fungal diversity indirectly via soil nutrients, while vegetation diversity exerted a direct effect. Collectively, these findings demonstrate that the effects of vegetation complexity on fungal communities are climate‐dependent, underscoring the need to integrate climatic context, vegetation management, soil nutrient regulation, and fungal ecological functions into roadside slope restoration.