CAS Key Laboratory of Mountain Ecological Restoration and Bioresource Utilization & Ecological Restoration Biodiversity Conservation Key Laboratory of Sichuan Province, Chengdu Institute of Biology, Chinese Academy of Sciences, P.O. Box 416, Chengdu, 610041, China; University of Chinese Academy of Sciences, Beijing, 100049, China; Department of Environmental Chemistry, University of Kassel, Witzenhausen, Germany.
Department of Environmental Chemistry, University of Kassel, Witzenhausen, Germany; Department of Soil Biology and Biochemistry, Dokuchaev Soil Science Institute, Russian Federation; Tyumen State University, 625003, Tyumen, Russia.
J Environ Manage. 2023 Sep 15;342:118119. doi: 10.1016/j.jenvman.2023.118119. Epub 2023 May 17.
The gap formation due to forest thinning regulates the understorey microclimate, ground vegetation, and soil biodiversity. However, little is known about abundant and rare taxa's various patterns and assemblage mechanisms under thinning gaps. Thinning gaps with increasing sizes (0, 74, 109, and 196 m2) were established 12 years ago in a 36-year-old spruce plantation in a temperate mountain climate. Soil fungal and bacterial communities were analyzed by MiSeq sequencing and related to soil physicochemical properties and aboveground vegetation. The functional microbial taxa were sorted by FAPROTAX and Fungi Functional Guild database. The bacterial community stabilized under varied thinning intensities and was not different from the control plots, whereas the richness of the rare fungal taxa was at least 1.5-fold higher in the large gaps than in the small ones. Total phosphorus and dissolved organic carbon were the main factors influencing microbial communities in soil under various thinning gaps. The diversity and richness of the entire fungal community and rare fungal taxa increased with the understorey vegetation coverage and shrub biomass after thinning. Gap formation by thinning stimulated the understorey vegetation, the rare saprotroph (Undefined Saprotroph), and mycorrhizal fungi (Ectomycorrhizal-Endophyte-Ericoid Mycorrhizal-Litter Saprotroph-Orchid Mycorrhizal and Bryophyte Parasite-Lichen Parasite-Ectomycorrhizal-Ericoid Mycorrhizal-Undefined Saprotroph), which may accelerate nutrient cycling in forest ecosystems. However, the abundance of Endophyte-Plant Pathogens increased by eight times, which showed the potential risk for the artificial spruce forests. Thus, fungi may be the driving force of forest restoration and nutrient cycling under the increasing intensity of thinning and may induce plant diseases. Therefore, vegetation coverage and microbial functional diversity should be considered to evaluate the sustainability of the artificial forest ecosystem and forest restoration.
森林疏伐导致的林隙形成调节了林下层小气候、地被植被和土壤生物多样性。然而，对于在疏伐林隙中丰富和稀有分类群的各种模式和组合机制，人们知之甚少。12 年前，在一个中纬度山区气候的 36 年生云杉人工林内建立了不同大小（0、74、109 和 196 m2）的疏伐林隙。通过 MiSeq 测序分析土壤真菌和细菌群落，并将其与土壤理化性质和地上植被相关联。通过 FAPROTAX 和 Fungi Functional Guild 数据库对功能微生物分类群进行排序。细菌群落受不同疏伐强度的稳定，与对照样地没有差异，而大型林隙中稀有真菌分类群的丰富度至少比小型林隙高 1.5 倍。总磷和溶解有机碳是影响不同疏伐林隙下土壤微生物群落的主要因素。整个真菌群落和稀有真菌分类群的多样性和丰富度随着林下植被覆盖度和灌木生物量的增加而增加。疏伐形成的林隙刺激了林下植被、稀有腐生菌（未定义腐生菌）和菌根真菌（外生菌根-内共生菌-内生菌根-外生菌根-腐生菌-兰菌根和苔藓寄生菌-地衣寄生菌-外生菌根-内生菌根-未定义腐生菌），这可能加速森林生态系统中的养分循环。然而，内生菌-植物病原菌的丰度增加了 8 倍，这表明人工云杉林存在潜在的风险。因此，真菌可能是森林在疏伐强度增加下恢复和养分循环的驱动力，并且可能导致植物病害。因此，为了评估人工森林生态系统的可持续性和森林恢复，应考虑植被覆盖度和微生物功能多样性。
