Abstract
Deadwood represents a key element in forests as it contributes to ecosystem functioning and provides habitat for a multitude of wood-dependent organisms. Decomposition of wood is the process responsible for carbon (C) and nutrients cycling, and wood-inhabiting fungi are considered the main drivers of decomposition due to their ability to degrade different C compounds. Fungal taxa showed specific habitat preferences and different degrees of specialization. Therefore, a deeper understanding of ecological factors that influence community structure and dynamics, may provide important indication on how and to what extent fungal communities respond to predicted global changes. However, still little is known on the topic and possible generalizations are hindered by methodological constraints and ecosystems variability. The main objectives of this thesis were to explore the habitat preferences and ecological drivers of wood-inhabiting fungal communities, starting from current knowledge improved with original field experiments. Different environmental attributes and forest types were chosen to obtain a more comprehensive view of fungal niche specialization across multiple spatial scales. A molecular approach (fingerprinting and sequencing) was used for the characterization of the fungal communities. Our general findings suggest that fungal community composition is affected by local factors that alter habitat and microhabitat conditions and the relative importance of such factors largely depend on the spatial scale adopted. Forest structural heterogeneity resulted the most important driver when comparing communities from sites with different characteristics, whereas at the substrate level, colonization patterns and interactions with other species within the community, play a greater role. These findings provided evidence of the complexity of fungal communities’ ecology and dynamics, and emphasize the need for a better evaluation of conservation-oriented silvicultural practices.