Soil fungal mycelium, abundance and species diversity as affected by fire in Mediterranean environment

The risk of accidental fires and fire severity is further destined to increase in Mediterranean European countries as a consequence of the climatic changes in progress. Fire may affect soil microbial community that regulates nutrient cycling in the terrestrial ecosystems. Previous studies have shown that fire causes an increase of total microbial biomass and activity and a reduction in functional diversity in soil of Mediterranean maquis. Aim of this study was to assess the effect of fire on soil fungi that are the main decomposers of plant litter. Fungal mycelium mass, abundance and species density were measured in burned and unburned soils. Fungal mycelium generally decreased during the first two years after fire; abundance and species density of total mycoflora decreased during the post-fire summer. Fungal mycelium, abundance and species density reached the lowest values during summer season with the lowest soil water content values, for both control and burned plots. Data suggest that fire represents, for soil fungal community, a disturbance superimposing to the soil water stress in the dry season in Mediterranean ecosystems and this effect is expected to increase in the next years on the basis of climatic change in progress.