Abstract
Fungi are the agents primarily responsible for the transformation of plant-derived carbon in terrestrial ecosystems. However, little is known of their responses to the seasonal changes in resource availability in deciduous forests, including photosynthate allocation belowground and seasonal inputs of fresh litter.
Vertical stratification of and seasonal changes in fungal abundance, activity and community composition were investigated in the litter, organic and upper mineral soils of a temperate Quercus petraea forest using ergosterol and extracellular enzyme assays and amplicon 454-pyrosequencing of the rDNA-ITS region. It was demonstrated that fungal activity, biomass and diversity decreased substantially with soil depth.
The highest enzyme activities were detected in winter, especially in litter, where these activities were followed by a peak in fungal biomass during spring. The fungal community composition was affected by season especially in the litter horizon, while the mineral soil horizon showed changes in biomass.
In the litter, saprotrophic genera reached their seasonal maxima in autumn, but summer typically saw the highest abundance of ectomycorrhizal taxa. Both litter decomposition and phytosynthate allocation represent important factors contributing to the observed seasonal changes.