Liu Size, Yin Haifeng, Li Xiangjun, Li Xianwei, Fan Chuan, Chen Gang, Feng Maosong, Chen Yuqin
College of Forestry, Sichuan Agricultural University, Chengdu, China.
Key Laboratory of State Forestry Administration for Forest Resources Conservation and Ecological Security in Upper Reaches of Yangtze River, Sichuan Agricultural University, Chengdu, China.
Front Microbiol. 2021 Mar 9;12:620309. doi: 10.3389/fmicb.2021.620309. eCollection 2021.
Thinning can significantly promote forest productivity and ecological function. Rhizosphere fungi play an indispensable role in regulating nutrient cycling between plants and the environment, and their community composition can positively respond to anthropogenic disturbance. However, the initial effects of thinning on rhizosphere fungal community assembly have seldom been reported. In this research, we studied the alterations in the rhizosphere fungal communities of 29-year-old in East Sichuan 2 years after three different thinning intensity treatments. In addition, the responses of fungal community and functional group composition to alterations in understory vegetation and soil physiochemical properties were analyzed. Three thinning intensities were set, which were 0 (CK), 25% (LIT), and 50% (HIT), respectively. The results suggested that the richness index and Shannon index of understory vegetation increased significantly with increasing thinning intensity. The alpha diversity indices of rhizosphere fungal community and soil physiochemical properties did not show significant differences among the three treatments. The relative abundances of 17 fungal indicator species varied regularly with increasing thinning intensity, and most of them belong to Hypocreales and Eurotiales, indicating that these two orders were potential indicators for different thinning treatments. Rhizosphere fungal community assembly was determined by deterministic process, and it was driven by the diversity of understory vegetation in the initial stage of thinning. The Simpson index and Pielou index of herbs were useful measures of the main environmental factors driving the differentiation of fungal functional group composition. Based on network analysis, thinning resulted in distinct co-occurrence patterns of rhizosphere fungal functional groups. This research elucidates the initial role of thinning in rhizosphere fungal community assembly of and has practical significance for the functional restoration and protection of local forest ecosystem.
间伐能显著提高森林生产力和生态功能。根际真菌在调节植物与环境之间的养分循环中发挥着不可或缺的作用，其群落组成能够对人为干扰做出积极响应。然而，间伐对根际真菌群落组装的初始影响鲜有报道。在本研究中，我们对川东地区29年生林分进行三种不同强度间伐处理两年后，研究了其根际真菌群落的变化。此外，还分析了真菌群落和功能组组成对林下植被和土壤理化性质变化的响应。设置了三种间伐强度，分别为0（对照）、25%（轻度间伐）和50%（重度间伐）。结果表明，林下植被的丰富度指数和香农指数随间伐强度增加而显著增加。三种处理下根际真菌群落的α多样性指数和土壤理化性质均无显著差异。17种真菌指示物种的相对丰度随间伐强度增加呈规律性变化，且大多属于肉座菌目和散囊菌目，表明这两个目是不同间伐处理的潜在指示菌。根际真菌群落组装由确定性过程决定，在间伐初期受林下植被多样性驱动。草本植物的辛普森指数和皮洛指数是驱动真菌功能组组成分化的主要环境因子的有效度量指标。基于网络分析，间伐导致根际真菌功能组出现明显的共现模式。本研究阐明了间伐在川东地区根际真菌群落组装中的初始作用，对当地森林生态系统的功能恢复和保护具有实际意义。
