Macrofungal Diversity and Fruiting Patterns in a Threatened Mediterranean Ecosystem: The Case of the Leonina Biancane (Tuscany, Italy)

Mediterranean badlands are highly dynamic, erosion-prone systems whose ecological communities are sensitive to climate and land use change. Despite extensive research on geomorphology, erosion and vegetation, their fungal communities remain unexplored. This study provides the first ecological characterization of macrofungal communities in the Leonina biancane badlands (southern Tuscany, Italy), a heterogeneous habitat mosaic characterized by active erosion and contrasting vegetation types. Macrofungi were surveyed weekly over two autumn seasons in 24 permanent plots across four different habitats. Event-based (plot × sampling date) and habitat-based (observations aggregated across the sampling period) approaches were used to assess temporal fruiting patterns, sampling completeness, plot positivity in relation to habitat and recent rainfall, habitat-level diversity and dominance patterns. Overall, 1603 sporocarps belonging to 122 species were recorded. Fruiting showed strong temporal discontinuity, with a high frequency of zero-richness events. Quasibinomial models indicated that plot positivity was influenced by both habitat type and 30-day accumulated rainfall (preceding sampling). Habitat acted as a local filter determining different baseline probabilities of sporocarp occurrence, while rainfall increased the probability of sporocarp occurrence across habitats. When observations were integrated through time, habitats differed in richness, diversity, dominance patterns and species composition, revealing clear differences in fungal community structure across the mosaic. Notably, pediments, i.e., sparsely vegetated erosion-exposed surfaces at the base of biancana domes, supported a distinctive fungal assemblage despite strongly episodic fruiting. These findings show that macrofungal diversity reflects both fine-scale habitat heterogeneity and temporal variability in fruiting, while highlighting the conservation relevance of threatened pediment habitats.