Effects of forest management on mycorrhizal fungi dispersal by small mammals in Alpine forests

Mycorrhizal associations are crucial for forest health, influencing nutrient cycling, plant growth, and forest resilience to disturbance. Many mycorrhizal fungi produce hypogeous sporocarps and rely on mycophagous animals, particularly small mammals, for spore dispersal. Despite the importance of these interactions, the effects of fine-scale forest management on mammal-mediated spore dispersal remains poorly understood. In this study, we (i) compared fungal spore communities dispersed by two widespread European small mammals, Apodemus flavicollis and Clethrionomys glareolus, and (ii) quantified which forest management–related habitat features most strongly influence both taxonomic richness and spore abundance in scat samples in subalpine forests of northern Italy. We collected scat samples from the yellow necked field mouse Apodemus flavicollis and the bank vole Clethrionomys glareolus across six sampling grids (replicated across three forest types subjected to different management regimes: a conifer reforestation, a logged beech forest, and an unmanaged mixed beech forest) over two consecutive years (2024–2025). Clethrionomys glareolus consistently dispersed more fungal taxa and spores than Apodemus flavicollis. We found a higher number of fungal taxa in unmanaged mixed beech forest compared to conifer reforestation and managed beech stands. We also found that stump volume, mean temperature during the 14 days preceding sample collection, and their interaction were the strongest predictors of both taxonomic richness and spore abundance. These findings suggest that retaining decaying wood and maintaining mixed-species stands can enhance animal-mediated fungal dispersal. Incorporating such features into forest management promote belowground biodiversity, thereby supporting key ecosystem functions such as nutrient cycling and regeneration.