Disentangling the effects of environmental and anthropogenic drivers on fungal fruitbody and spore diversity in a Mediterranean coniferous forest

Wild macrofungal species are important non-wood forest products in Mediterranean forests, where their ability to release and disperse spores is crucial for completing their life cycle. However, the ecological drivers behind fruitbody production and fungal spore dispersal and deposition remain poorly understood. Here, we assessed the effect of silvicultural management, topography, and weather on macrofungal fruitbody and deposited spore community composition and diversity in a subalpine Mediterranean pine-dominated forest by sampling deposited spores and fungal fruitbodies in 9 paired plots (thinned vs. control) across a 300-m altitudinal gradient from September to November 2021. Spore trap filters were analyzed through ITS2 metabarcoding, while the collected fruitbodies were visually identified. Our results showed that weather fluctuations accounted for the greatest proportion of variance in spore composition for both ectomycorrhizal (15 %) and saprotrophic species (15 %). In contrast, weather explained only a small portion of variance for fruitbodies (2.6 % for the ectomycorrhizal and 0.6 % for the saprotrophic species). Interestingly, topography explained a larger amount of variance for saprotrophic spores and fruitbodies (4.67 % and 1.51 %, respectively) compared to the ectomycorrhizal groups (0.7 % and <0.1 %, respectively), highlighting the spatial dependency of saprotrophic fungi. Contrary to expectations, forest thinning intensity accounted for a non-significant part of the variance for both fruitbodies and spores. Our findings demonstrate the significant role of weather and topography in shaping fungal spore dispersion and fruitbody production in Mediterranean forests, with implications for fungal reproduction strategies and forest management.