Influence of tree species on richness and diversity of epigeous fungal communities in a French temperate forest stand

Epigeous saprotrophic and ectomycorrhizal (ECM) fungal sporocarps were assessed during 7 yr in a French temperate experimental forest site with six 30-year-old mono-specific plantations (four coniferous and two hardwood plantations) and one 150-year-old native mixed deciduous forest. A total of 331 fungal species were identified. Half of the fungal species were ECM, but this proportion varied slightly by forest composition. The replacement of the native forest by mono-specific plantations, including native species such as beech and oak, considerably altered the diversity of epigeous ECM and saprotrophic fungi. Among the six mono-specific stands, fungal diversity was the highest in Nordmann fir and Norway spruce plantations and the lowest in Corsican pine and Douglas fir plantations. Several factors, connected to the mono-specificity of host trees, could be involved in regulating fungal diversity. Interestingly, this study showed a significant negative correlation between fungal species richness and nitrogen mineralisation, indicating that increases in mineral N availability are associated with decline in saprotrophic and ECM community richness. The frequency of occurrence of fruit bodies of 11 edible fungal species that naturally occur in the native forest was modified by the treatments.