1.State Key Laboratory of Herbage Improvement and Grassland Agro-ecosystems, College of Pastoral Agricultural Science and Technology, Lanzhou University;2.tate Key Laboratory of Herbage Improvement and Grassland Agro-ecosystems, College of Pastoral Agricultural Science and Technology, Lanzhou University, Lanzhou;3.College of Resources and Environmental Sciences, Nanjing Agricultural University/Jiangsu Provincial Key Laboratory of Solid Organic Waste Utilization, Nanjing
Supported by the National Natural Science Foundation of China (No. 42277100)
【Objective】This study aimed to clarify the general rules of the impact of grazing on the composition and function of soil fungal communities in northern grasslands of China, and to provide the theoretical foundation for ecological conservation efforts in these grasslands. 【Method】This study collected 119 raw data of soil fungi from different studies in grazed grasslands, used unified bioinformatics processing methods and meta-analysis to demonstrate the changes in α-diversity, community composition and functional groups of soil fungi within grazed grasslands, and used weighted mixed-effects models for environmental factor analysis. 【Result】The results indicated that grazing reduced the soil fungal α-diversity and significantly decreased the relative abundance of pathotrophic fungi, wood saprotrophic fungi, soil saprotrophic fungi, and endophytic fungi. The change in grazing soil fungal α-diversity and functional fungal relative abundance depended on altered environmental factors in different regions. The negative effect of grazing on soil fungal α-diversity was mitigated to some extent in the regions with lower organic carbon content, lower carbon-to-nitrogen ratio, and higher annual precipitation. Initial soil organic carbon content and grazing exclusion duration influenced the variations in functional fungal abundance, with long-term grazing exclusion promoting the recovery of soil saprotrophic and symbiotrophic fungi communities. As the initial carbon-to-nitrogen ratio increased, the degree of reduction in the relative abundance of pathotrophic fungi under grazing decreased. In contrast, the degree of reduction in the relative abundance of saprotrophic fungi increased. Importantly, in regions with lower precipitation, grazing had a more significant impact on reducing the relative abundance of saprotrophic and symbiotrophic fungi. 【Conclusion】Overall, grazing negatively affected the α-diversity and functional traits of soil fungal communities in the northern grasslands of China. However, the degree and direction of this effect depended on the local environmental conditions.