Li Yuyu, Zhao Lixing, Hilal Mian Gul, Guo Lizhu, Zhang Yandong, Ji Yu, Jiang Xiaowei, Hao Lifen, Lin Kejian
Institute of Grassland Research, Chinese Academy of Agricultural Science, Hohhot, China.
Key Laboratory of Biohazard Monitoring, Green Prevention and Control for Artificial Grassland, Ministry of Agriculture and Rural Affairs, Hohhot, China.
Front Microbiol. 2024 Nov 18;15:1438787. doi: 10.3389/fmicb.2024.1438787. eCollection 2024.
Grassland which covers 40% of terrestrial land is an important ecosystem having a multitude of functions, which has suffered various degrees of degradation with the interaction between global climate change and unreasonable human utilization (e.g., grazing and reclamation). Improved understanding of soil and microbial community diversity during meadow steppe degradation is crucial for predicting degradation mechanisms and restoration strategies. Here, we used Illumina sequencing technology to investigate the patterns of soil microbial community structure and the driving factors of its change across different degradation degrees of meadow steppe [i.e., non-degraded grasslands (NDG), lightly degraded grasslands (LDG), moderately degraded grasslands (MDG), and severely degraded grasslands (SDG)] south of the Greater Khingan Mountains. Our results showed a significant variation in soil properties, enzyme activity, and soil metal elements across the degraded meadows. Soil available phosphorus (AP), urease (UE), and cellulase (CL) in soils increased with the intensity of grassland degradation. Grassland degradation significantly decreased soil bacterial and fungal richness. In addition, grassland degradation significantly increased the relative abundance of Firmicutes (from 1.65% to 5.38%) and Myxococcota (from 2.13% to 3.13%). Degradation considerably increased the relative abundance of Ascomycota (from 66.54% to 75.05%), but decreased Basidiomycota (from 18.33% to 9.92%). The relative abundance of nitrogen fixation and cellulolysis decreased significantly due to grassland degradation. For fungal functional guilds, the relative abundance of pathotrophs increased while saprotrophs decreased significantly with increasing severity of degradation. Total nitrogen (TP), AP, available potassium (AK), manganese (Mn), lead (Pb), UE, sucrase (SC), and alcalase protease (ALPT) were the main drivers of soil bacterial community composition, while TP, AP, AK, Pb, UE, and SC were the main drivers of soil fungal community composition in the degraded grassland. Our findings demonstrated that severe grassland degradation has an enormous effect on soil microbial communities and soil physicochemical dynamics. These findings improve our theoretical understanding of the interactions between soil microbial populations and soil environmental variables in degraded grassland.
覆盖40%陆地面积的草原是一个具有多种功能的重要生态系统，随着全球气候变化与不合理的人类利用（如放牧和开垦）相互作用，该生态系统已遭受不同程度的退化。更好地了解草甸草原退化过程中的土壤和微生物群落多样性，对于预测退化机制和恢复策略至关重要。在此，我们利用Illumina测序技术，研究了大兴安岭南部不同退化程度的草甸草原（即未退化草原（NDG）、轻度退化草原（LDG）、中度退化草原（MDG）和重度退化草原（SDG））土壤微生物群落结构模式及其变化的驱动因素。我们的结果表明，退化草甸的土壤性质、酶活性和土壤金属元素存在显著差异。土壤有效磷（AP）、脲酶（UE）和纤维素酶（CL）随草原退化强度增加而增加。草原退化显著降低了土壤细菌和真菌的丰富度。此外，草原退化显著增加了厚壁菌门（从1.65%增至5.38%）和粘球菌门（从2.13%增至3.13%）的相对丰度。退化显著增加了子囊菌门的相对丰度（从66.54%增至75.05%），但降低了担子菌门的相对丰度（从18.33%降至9.92%）。由于草原退化，固氮和纤维素分解的相对丰度显著降低。对于真菌功能类群，随着退化程度的加重，致病营养型的相对丰度增加，而腐生营养型的相对丰度显著降低。总磷（TP）、AP、速效钾（AK）、锰（Mn）、铅（Pb）、UE、蔗糖酶（SC）和碱性蛋白酶（ALPT）是退化草原土壤细菌群落组成的主要驱动因素，而TP、AP、AK、Pb、UE和SC是退化草原土壤真菌群落组成的主要驱动因素。我们的研究结果表明，严重的草原退化对土壤微生物群落和土壤理化动态有巨大影响。这些发现增进了我们对退化草原土壤微生物种群与土壤环境变量之间相互作用的理论理解。
