The ecological restoration of degraded alpine steppe is a critical component of ecological conservation efforts on the Qinghai–Tibetan Plateau. In this study, we investigated the effects of fertilization, reseeding, and combined fertilization with reseeding restoration measures on the vegetation community, soil properties and microbial community diversity in degraded alpine steppe through field vegetation surveys, and soil microbial high-throughput sequencing at an experimental site of fertilized and reseeded grassland restoration located in the Yellow River Source area. The results demonstrated the following: (1) both reseeding and combined fertilization with reseeding restoration measures significantly affected grassland vegetation community structure and diversity; (2) fertilization and combined fertilization with reseeding restoration measures significantly affected soil pH and total phosphorus (TP) content; (3) while fertilization and combined fertilization with reseeding restoration measures markedly altered microbial community structure, reseeding alone significantly affected microbial diversity. Co-occurrence network analysis revealed that soil microbial communities were significantly influenced by fertilization restoration measures; redundancy analysis (RDA) showed that microbial communities under fertilization and combined fertilization with reseeding restoration measures were primarily governed by soil TP, whereas those in control and reseeding plots were strongly associated with soil pH and organic carbon (SOC). This study explored effective restoration measures suitable for degenerating alpine steppe in the Yellow River Source area, aiming to provide a scientific basis and technical support for the ecological protection and restoration of the Three-River Headwaters.

Alpine grasslands and alpine deserts represent two major ecosystems on the Tibetan Plateau. However, whether the two ecosystems differ in soil microbial community diversity and co-occurrence network structure remains poorly understood. This study assessed the composition and diversity of soil bacterial communities across alpine grasslands and alpine deserts on the Tibetan Plateau via 16S high-throughput sequencing, analysis of variance (ANOVA), mantel test, and other methods. Our results revealed that soil alkaline-hydrolyzable nitrogen (SAN), soil total nitrogen (STN), soil total phosphorus (STP), soil available phosphorus (SAP), and soil organic carbon (SOC) were significantly higher in grassland than in desert (p < 0.05). The microbial community composition and diversity differed significantly between alpine grasslands and alpine deserts. Analysis of microbial co-occurrence networks revealed that grassland systems possessed significantly more nodes, edges, and a higher average degree than desert systems, along with greater network robustness—indicating a more complex and stable microbial community structure. Correlation analysis further revealed that SOC and STN were positively correlated with microbial diversity, while electrical conductivity (EC), SOC, STN, and SAN showed positive associations with microbial community composition. In conclusion, alpine grasslands harbor greater soil microbial diversity and more stable microbial co-occurrence networks than alpine deserts, suggesting that alpine grasslands may hold greater ecological value than alpine deserts in maintaining soil biodiversity and ecosystem functioning. This study not only elucidates the distribution patterns and diversity of soil microbial communities across Tibetan grasslands, but also offers critical insights into the mechanisms governing ecosystem functioning, thereby informing ecological conservation and sustainable management strategies on the plateau.