Dynamics of ectomycorrhizal communities in Sardinian cork oak stands

Abstract: The dynamic of ectomycorrhizal communities was investigated in three cork oak areas characterized by different geologic substrate (granitic, basaltic, trachytic), which are representative of the Sardinian cork oak surface. In each area three cork oak stands differing in management system (natural, grazed, grazed with soil tillage for sowing annual forage crops) were selected. For each of the nine geological substrate-management system combination, a rectangular transect was established for spring and autumn sampling. In each period, 10 soil samples were collected and all ectomycorrhizae observed were identified based on both morphology and molecular analysis.The results showed that the diversity of ectomycorrhizal fungal communities changes in stands with different management types, regardless of the geological substrate. In particular, the richness in fungal species decreased when human pressure increased. A further erosion of diversity was detected in cork oak stands subjected to soil tillage for sowing of annual forage crops. These findings highlight the ability of ectomycorrhizal community to tolerate a certain degree of human pressure, but also the harmful consequence of overexploitation on ectomycorrhizal community diversity.