Functional diversity of dead wood promotes species-rich communities of fungi

Dead wood is a vital structural element in boreal forests, supporting diverse fungal and insect communities. Wood-inhabiting fungi, in particular, are influenced by both the volume and characteristics of dead wood. However, forestry practices often reduce dead wood quantity and diversity, impacting these communities. This study investigates how different facets of dead wood functional diversity − richness, evenness, divergence, and dispersion − alongside volume, affect fruiting polyporoid and corticioid fungi in Agaricomycetes. Using a paired design of previously clear-cut and near-natural forests, we assess fungal responses to dead wood traits. Our findings show that near-natural forests host greater fungal species richness due to higher dead wood volume and diversity. A combined measure of volume and functional diversity better predicts fungal richness and composition than either factor alone. Notably, functional divergence and evenness are key indicators of niche variety and distribution. These results emphasize the need to enhance both quantity and structural diversity of dead wood in forest management.