The degradation of alpine meadows on the Qinghai–Tibet Plateau is a major issue affecting both the ecology and the economy. Microorganisms play an important role in soil nutrient cycling and the regulation of ecosystem function. This study aimed to investigate the species composition and diversity of microbial communities and understand the response of microbial communities to changes in physicochemical properties resulting from meadow degradation. In this study, the soil bacterial and fungal communities’ composition and diversity of alpine meadows of degradation gradient were sequenced by high-throughput sequencing. During the process of grassland degradation, there were 59 bacterial taxa and 29 fungal taxa showing significant differences. The relative abundance of meadow pathogenic fungi significantly increased (p < 0.05). PICRUSt2 analysis showed a decrease in synthesis-related functional gene abundance and an increase in metabolism-related functional gene abundance. FUNGuild analysis showed that symbiotic and saprophytic nutrient fungi decreased significantly (p < 0.05). The soil nutrient cycling was mainly influenced by the beta diversity of microbial communities. Grassland degradation affects soil structure, thereby affecting the diversity of soil microbial composition and functional soil nutrient content. This work reveals the response of microbial communities to the degradation of alpine meadows and their impact on nutrient cycling, providing theoretical support for the protection and sustainable development of alpine meadows.

Tibetan sheep (Ovis aries) and plateau pika (Ochotona curzoniae) excrements are important organic materials that influence soil carbon cycling in the Qinghai-Tibetan Plateau. However, their exact priming effects (PE) on soil and mechanisms of influence in alpine meadows are subject to their health status. To fill this knowledge gap, we carried out a 45-day incubation experiment using alpine meadow soils with differing degrees of degradation that had been enriched with these two types of excrement. Soil PE was assessed via the natural abundance method, while soil microbial communities and their compositions were examined through high-throughput sequencing. The findings indicated that severely degraded alpine meadow soils exhibit significantly stronger positive priming effects (PE) from Tibetan sheep and plateau pika excrements than non-degraded soils (P < 0.05). These excrements restructure soil microbial communities, reducing bacterial α-diversity while increasing β-diversity and microbial biomass C:N ratios. Key microbial drivers of PE include Actinobacteriota (positive correlation, r = 0.70) and Proteobacteria (negative correlation, r = −0.52), whose abundances are modulated by soil properties: the C:N ratio promotes Proteobacteria (r = 0.39), while a lower NO3--N:NH4+-N ratio suppresses Actinobacteriota (r = −0.18). Meadow degradation thus indirectly intensifies PE by altering these microbial phylum and stoichiometric balances. These findings support Qinghai-Tibetan Plateau grassland management through: (1) restricting grazing/pika activity in degraded zones to reduce carbon loss, (2) optimizing soil C:N ratios to suppress priming effect (PE)-enhancing microbes, and (3) conserving intact meadows for carbon sequestration—collectively enabling sustainable grassland management.

Tibetan sheep (Ovis aries) and plateau pika (Ochotona curzoniae) excrements are important organic materials that influence soil carbon cycling in the Qinghai-Tibetan Plateau. However, their exact priming effects (PE) on soil and mechanisms of influence in alpine meadows are subject to their health status. To fill this knowledge gap, we carried out a 45-day incubation experiment using alpine meadow soils with differing degrees of degradation that had been enriched with these two types of excrement. Soil PE was assessed via the natural abundance method, while soil microbial communities and their compositions were examined through high-throughput sequencing. The findings indicated that severely degraded alpine meadow soils exhibit significantly stronger positive priming effects (PE) from Tibetan sheep and plateau pika excrements than non-degraded soils (P < 0.05). These excrements restructure soil microbial communities, reducing bacterial α-diversity while increasing β-diversity and microbial biomass C:N ratios. Key microbial drivers of PE include Actinobacteriota (positive correlation, r = 0.70) and Proteobacteria (negative correlation, r = −0.52), whose abundances are modulated by soil properties: the C:N ratio promotes Proteobacteria (r = 0.39), while a lower NO₃^--N:NH₄⁺-N ratio suppresses Actinobacteriota (r = −0.18). Meadow degradation thus indirectly intensifies PE by altering these microbial phylum and stoichiometric balances. These findings support Qinghai-Tibetan Plateau grassland management through: (1) restricting grazing/pika activity in degraded zones to reduce carbon loss, (2) optimizing soil C:N ratios to suppress priming effect (PE)-enhancing microbes, and (3) conserving intact meadows for carbon sequestration—collectively enabling sustainable grassland management.

Tibetan sheep (Ovis aries) and plateau pika (Ochotona curzoniae) excrements are important organic materials that influence soil carbon cycling in the Qinghai-Tibetan Plateau. However, their exact priming effects (PE) on soil and mechanisms of influence in alpine meadows are subject to their health status. To fill this knowledge gap, we carried out a 45-day incubation experiment using alpine meadow soils with differing degrees of degradation that had been enriched with these two types of excrement. Soil PE was assessed via the natural abundance method, while soil microbial communities and their compositions were examined through high-throughput sequencing. The findings indicated that severely degraded alpine meadow soils exhibit significantly stronger positive priming effects (PE) from Tibetan sheep and plateau pika excrements than non-degraded soils (P < 0.05). These excrements restructure soil microbial communities, reducing bacterial α-diversity while increasing β-diversity and microbial biomass C:N ratios. Key microbial drivers of PE include Actinobacteriota (positive correlation, r = 0.70) and Proteobacteria (negative correlation, r = −0.52), whose abundances are modulated by soil properties: the C:N ratio promotes Proteobacteria (r = 0.39), while a lower NO₃^--N:NH₄⁺-N ratio suppresses Actinobacteriota (r = −0.18). Meadow degradation thus indirectly intensifies PE by altering these microbial phylum and stoichiometric balances. These findings support Qinghai-Tibetan Plateau grassland management through: (1) restricting grazing/pika activity in degraded zones to reduce carbon loss, (2) optimizing soil C:N ratios to suppress priming effect (PE)-enhancing microbes, and (3) conserving intact meadows for carbon sequestration—collectively enabling sustainable grassland management.