Abstract
The diversity of ectomycorrhizal fungi is high even at small spatial scales but the factors determining this are largely unknown. Stratified mineral podzol soils exhibit a range of different soil conditions. Patterns of species diversity in relation to soil horizon have been demonstrated for fungi colonising root tips and forming mycelia in a podzol soil. The aim of this project is to identify functional differences between ectomycorrhizal species to determine the relative importance of abiotic preferences versus biotic interactions for the large diversity of these fungi in soil. Field studies of the realised niche of different species will determine the correlative relation between available nutrient resources and species distribution at a spatial scale relevant to soil heterogeneity and mycelial size. Experimental studies of the potential niche of different species will determine the causal relation between fungal species and complex natural substrates. Detailed analysis of fungal regulation of enzymatic and biogeochemical activity will determine species-specific responses to relevant inorganic and organic nitrogen and phosphorus substrates. Comparing the realized niche of a species in soil with its potential niche in vitro will demonstrate to what degree species-specific resource utilization determines their distribution in the field. This will shed light upon the significance of fungal biodiversity for the ecosystem function of boreal forest.
Sweden