Response of fungal communities to afforestation and its indication for forest restoration

Soil fungi in forest ecosystems have great potential to enhance host plant growth and systemic ecological functions and services. Reforestation at Saihanba Mechanized Forest Farm, the world's largest artificial plantation, has been integral to global forest ecosystem preservation since the 1950s. To better assess the ecological effects of soil microbiology after afforestation, fungal diversity and community structure (using Illumina sequencing) from forests dominated by Larix gmelinii var. principis-rupprechtii, Pinus sylvestris var. mongolica and Picea asperata, and from grassland were surveyed. In total, 4,540 operational taxonomic units (OTUs) were identified, with Mortierella and Solicoccozyma being the dominant genera of grassland soil and Inocybe, Cortinarius, Piloderma, Tomentella, Sebacina, Hygrophorus and Saitozyma dominating the plantation soil. Principle coordinate analysis (PCoA) and co-occurrence networks revealed differences in fungal structure after afforestation. Significantly, more symbiotroph guilds were dominated by ectomycorrhizal fungi in plantations under the prediction of FUNGuild. The community composition and diversity of soil fungi were significantly influenced by pH via redundancy analysis (RDA) and the Mantel test (p < 0.01). This finding emphasizes that soil pH has a strong effect on the transition of fungal communities and functional taxa from grassland to plantation, providing a novel in-dicator for forest restoration.