A multi-proxy approach links pedological context to fungal community variation in temperate mountain forest soils

Background: Soil fungi play a key role in nutrient cycling and soil organic matter turn-over, yet the influence of pedological context on fungal communities across forest types remains insufficiently understood. Methods: Here, we combined soil chemical analyses, Fourier-transform infrared spectroscopy (FTIR) and ITS metabarcoding to investigate soil properties and fungal communities in temperate mountain beech (Fagus sylvatica L.) and Norway spruce (Picea abies (L.) H.Karst) forests in Italy developed on contrasting geological substrates. Soil horizons were sampled across seasons to characterize the main associations between fungal community structure, inferred functional diversity, and environmental context. Results: Soil chemistry revealed site and horizon dependent patterns, particularly in pH, Ca and P availability, whereas differences related to dom-inant tree species were comparatively limited. FTIR spectra showed clear variation in organic matter composition among sites, consistent with substrate and litter driven processes. Fungal community composition was primarily structured by site and soil horizon. Functional guild patterns suggested ectomycorrhizal dominance in Ca-rich soils and greater saprotrophic prevalence in more acidic soils. Conclusion: Overall, this mul-ti-proxy approach suggests that pedological context was more closely associated with fungal community structure and ecological strategies than vegetation or season within the studied stands. These patterns should be interpreted as site-specific and hypothe-sis-generating because substrate types were not replicated across independent locations.