Ectomycorrhizal (ECM) fungi, as symbionts of many tree species in temperate forests, are thought to play an important role in forest regeneration processes after large disturbances. Their reaction to different disturbance and management regimes was studied in spruce forests (Lariceto-Piceetum) 10 years after a severe windthrow in the Tatra National Park (Slovak Republic). ECM community structure was compared between different "management types″-cleared area (EXT), area affected by wildfire (FIRE), uncleared area left for natural development (NEX), and mature forest as a control (REF). Based on Illumina sequencing of soil samples, we determined that the percentage of sequences assigned to ECM fungi decreased with increasing disturbance and management intensity (REF → NEX → EXT → FIRE). Similarly, the total number of ECM species per each of ten sampling points per plot (100 ha) differed between managed (EXT-11 species, FIRE-9) and unmanaged (NEX-16, REF-14) treatments. On the other hand, the percentage of sequences belonging to ericoid mycorrhizal fungi increased. Management type significantly influenced the composition of the ECM community, while vegetation and soil characteristics explained less data variation. The ECM species assemblage of the unmanaged site (NEX) was the most similar to the mature forest, while that of the burnt site was the most different. Thelephora terrestris dominated in all treatments affected by windthrow, accompanied by Tylospora fibrillosa (NEX) and Tylospora asterophora (EXT and FIRE). Management regime was also the most important factor affecting ECM species composition on the roots of spruce seedlings assessed by Sanger sequencing.
Keywords: Ectomycorrhiza; Fire; Forest regeneration; Fungi; Next generation sequencing; Picea abies; Windthrow.