Abstract Soil fungal communities play a key role in multiple ecosystem functions and services within forest ecosystems. Today, forest ecosystems are subject to multiple environmental and anthropogenic disturbances (e.g. fires or forest management) that cause changes in vegetation and in the interactions between plants and soil. In this study, we analyzed the response of soil fungi to forest management in an over 50-year-old Pinus pinaster afforestation site in Guadalajara, Spain. We started from an experimental setting in which silvicultural treatments of thinning and clear-cutting gaps were applied, with different intensities and sizes, respectively. Five years after the treatments, soil was sampled during the spring at a depth of 15 cm along transects (in thinning), in circular subplots (in gaps), and in the control plots. DNA extraction was performed, and for metabarcoding, we used a fungal internal transcribed spacer (ITS2) and high-throughput sequencing with the Illumina platform. The predominant trophic groups (determined by the genus of the fungi) were soil saprophytes, dominated by the genus Mortierella, as well as ectomycorrhizal (ECM) fungi, dominated by the genus Inocybe. Thinning significantly increased the richness and diversity indexes of fungal OTUs (Operational Taxonomic Units) compared to gaps. Moderate low thinning (B20) increased fungal richness without altering community fungal structure. The combination of thinning and coarse woody material (24 m3/ha) increased soil fungal richness but not the other diversity indexes. Thinning treatment increased the ECM genus Russula. The phytopathogen Venturia was highly present in areas with little or no disturbance, while a strong low thinning (B35) reduced Venturia and altered the plant pathogen fungal community. In contrast, a high thinning (A35) did not affect the structure of trophic groups in any case. The diameter of the gaps did not affect the main genera, but large diameter gaps (44 m) increased nonspecific fungal saprophytes. Five years after treatment application, the regeneration of pine and Cistus sp. in the central area of the gaps increased the litter saprophytes and led to a strong replacement of fungal species in this area. We hypothesize that the gaps caused significant changes in the dynamics of organic matter decomposition, although the ECM fungal community was not reduced. Five years after the silvicultural treatments, the soil fungal community has managed to preserve or adapt its trophic functions, even in the center of the gaps.
Martos et al. (Mon,) studied this question.