Response of Soil Fungal Community to Reforestation on Shifting Sand Dune in the Horqin Sandy Land, Northeast China

Reforestation of native shrub on shifting sand dunes has been widely used for desertification control in semi-arid grassland in Northeast China. Previous studies have confirmed that plantation establishment facilitates fixing sand dunes, restoring vegetation, and improving soil properties, but very few have focused on the response of the soil fungal community. In this study, a chronosequence of Caragana microphylla (CM) shrub sand-fixation plantations (8-, 19-, and 33-year-old), non-vegetated shifting sand dunes (0 years), and adjacent natural CM forests (NCFs; 50-year-old) in the Horqin sandy land were selected as experimental sites. Soil properties including enzymatic activities were determined, and the composition and structure of the soil fungal community were investigated using the Illumina MiSeq sequencing technique based on the internal transcribed spacer (ITS) rDNA. This study aimed to (1) describe the response of the soil fungal community to revegetation onto a moving sand dune by planting a native shrub plantation; (2) determine the main soil factors driving the succession of the fungal community; and (3) discuss whether the soil fungal community can be restored to its original state by reforestation. The reforestation of CM significantly ameliorated soil properties, increased soil fungal diversity, and altered the composition and structure of the soil fungal community. Ascomycota, Basidiomycota, and Zoopagomycota were the dominant phyla in all sites. Ascomycota did not respond to plantation development, whereas the other two dominant phyla linearly increased or decreased with the plantation age. The relative abundance of dominant genera varied with sites and showed a waning and waxing characteristic. The composition and structure of the soil fungal community in the 33-year CM plantation were very close to that of the NCF, indicating the restorability of the soil fungal community. The succession of the soil fungal community was directly driven by soil properties, of which soil moisture, organic matter, total N, urease, and protease were the main affecting factors.

The Effects of Drainage on the Soil Fungal Community in Freshwater Wetlands

Wetland drainage has been intensively implemented globally, and it has exerted significant effects on wetland ecosystems. The effects of wetland drainage on the soil fungal community remain to be clarified. Soil samples were collected at depths of 0–5 and 5–10 cm in freshwater Phragmites australis wetlands to investigate changes in the fungal community before and after drainage (termed FW and DFW, respectively) using high-throughput sequencing of the fungal-specific internal transcribed spacer 1 (ITS1) gene region. No significant differences in the α diversity of the soil fungal community were found in 0–10 cm soils between FW and DFW (p > 0.05), except for the abundance-based coverage estimator (ACE) and Chao1 indices in 5–10 cm soils. Significantly higher values of ACE and Chao1 in 5–10 cm soils in FW than in DFW indicated that wetland drainage may reduce fungal community richness in 5–10 cm soils. Ascomycota, Sordariomycetes, and Cephalothecaceae were the dominant fungal phylum, class, and family, respectively, in 0–5 and 5–10 cm soils of both FW and DFW, representing as high as 76.17, 58.22, and 45.21% of the fungal community in 5–10 FW soils, respectively. Saprotrophic fungi predominated in both FW and DFW. Drainage altered both the fungal community structure and some edaphic factors. Mantel tests and Spearman correlation analyses implied that edaphic factors [i.e., soil organic matter (SOM), electronic conductivity (EC), pH, and clay] also affected soil fungal community structure. Overall, wetland drainage altered the community structure of the fungal community in the freshwater wetlands.

Fungal Diversity

Fungi play key roles at two levels of ecological organization: in communities, fungi are symbionts of plants and animals, while in ecosystems, fungi are decomposers that recycle nutrients to other organisms [...]