Effects of oak, beech and spruce on the distribution and community structure of fungi in litter and soils across a temperate forest

Abstract Understanding the factors that structure soil microbial communities and their relative importance in determining local community assemblages is fundamental to understanding how human activities, such as forest management, may impact soil ecosystems. We studied fungal communities in soil and litter under multiple sites dominated by spruce, beech and oak in a central European forest ecosystem to further understand the relative importance of vegetation and abiotic variables within a temperate forest. We sampled four times over a one-year period to determine if fungal community composition varied over time and whether the determination of driving factors was temporally dependent. We found that fungal community composition differed between litter and soil and among stand types but that community structure (richness, functional-guilds) was similar. In litter communities, composition was strongly coupled to dominant tree species; while in soil communities, both dominant tree and abiotic variables such as pH were important - with each variable explaining a separable portion of the variation in the fungal community composition. Further analyses showed that the relative importance of dominant tree species and abiotic drivers differed among functional groups subsets of the community. Across our sampled sites, both the litter and soil communities of a given stand type were well-characterized by a set of low-abundance indicator species with consistent presence, regardless of location, suggesting stand type is an important local filter on the occurrence of these taxa within the spatial context of our study (100 km 2 ). The marked difference in annual leaf break and leaf fall between coniferous and deciduous stands were not found to correlate with temporal changes in fungal community composition; however, a time-dependent trend was found across all soil communities and among all soil functional-group subsets regardless of the dominant tree type.