Here we report on ecology and biodiversity of fungi in a unique mycological sanctuary in Britain, where data on species composition have been collected since 1994. To complement the biodiversity data by the information on the fungal ecological interactions and their role in the overall ecosystem functioning, soil properties and the composition of forest litter and field layer, bacterial population numbers and fungal biomass (in terms of ergosterol) were measured in 8 plots covered with different vegetations (beech, birch, birch-oak-beech, grass) over a May–Aug. period, and the results were analysed by correlation analysis and stepwise regression modelling together with data on protozoa and nematodes available from parallel research. The results highlighted the complexity of factors influencing temporal dynamics and spatial variability of fungal biomass in soil and forest litter. Most of the registered interactions appeared to be transient, and this should be taken into account while interpreting environmental observations. Interpretation of the specific relationships is given and implications for further research and overall ecosystem functioning are discussed.