Cascading impacts of nitrogen deposition on soil microbiome and herbivore communities in desert steppes

• Published in: The Science of the total environment 2024-12, Vol.955, p.176892, Article 176892
• Main Authors: Liu, Jingxi, Zhu, Mengmeng, Shi, Xiangfeng, Hui, Cang, Sun, Yurong, Zhang, Rong, Jin, Decai, Li, Zhihong, Chen, Honghao, Zhao, Zihua
• Format: Article
• Language: English
• Subjects: Animals; Biodiversity; China; Community structure; Desert Climate; Desert steppe; Ecosystem; Grassland; Herbivory; Insect; Insecta - physiology; Microbiota - drug effects; Nitrogen; Nitrogen deposition; Plant community; Soil - chemistry; Soil Microbiology; Soil microbiome
• ISSN: 0048-9697; 1879-1026; 1879-1026
• DOI: 10.1016/j.scitotenv.2024.176892

Human activities in the last century have intensified global nitrogen deposition, resulting in the degradation of ecosystem function and loss of biodiversity worldwide. Nitrogen addition is a crucial method for examining the effects of atmospheric nitrogen deposition on species composition and structure of soil microbiome and biotic community, as exogenous nitrogen inputs can trigger cascading effects on ecosystem functions. In a 6-year experiment, we evaluated the impact of nitrogen addition on soil microbial-plant-insect systems in desert steppes. Our results show that nitrogen addition significantly altered soil microbial composition and ecological function, leading to a decrease in nitrogen-fixing bacteria and an increase in saprophytic fungi. High levels of nitrogen addition increased total plant biomass while decreasing species diversity. Additionally, high nitrogen addition levels suppressed below-ground biomass of gramineae and legumes compared to low nitrogen addition. Nitrogen addition also increased herbivore abundance by altering insect community structure, particularly benefiting chewing pests over sucking pests, thus heightening the risk of biological disasters through trophic cascading effects. Consequently, excessive nitrogen addition may destabilize desert steppe ecosystems by disturbing soil microbial-plant-insect interactions, hindering the maintenance of biotic community diversity and steppe productivity. [Display omitted] •Nitrogen addition significantly altered soil microbial composition and ecological function.•High nitrogen addition suppressed below-ground biomass of gramineae and legumes compared to low nitrogen.•Nitrogen addition also increased herbivore abundance by altering insect community structure.•Excessive nitrogen addition may destabilize desert steppe ecosystems by affecting soil microbial-plant-insect interactions