Arbuscular mycorrhizal fungi (AMF), playing critical roles in carbon cycling, are vulnerable to climate change. However, the responses of AM fungal abundance to climate change are unclear. A global-scale meta-analysis was conducted to investigate the response patterns of AM fungal abundance to warming, elevated CO₂ concentration (eCO₂), and N addition. Both warming and eCO₂ significantly stimulated AM fungal abundance by 18.6% (95%CI: 5.9%–32.8%) and 21.4% (15.1%–28.1%) on a global scale, respectively. However, the response ratios (RR) of AM fungal abundance decreased with the degree of warming while increased with the degree of eCO₂. Furthermore, in warming experiments, as long as the warming exceeded 4 °C, its effects on AM fungal abundance changed from positive to negative regardless of the experimental durations, methods, periods, and ecosystem types. The effects of N addition on AM fungal abundance are −5.4% (−10.6%–0.2%), and related to the nitrogen fertilizer input rate and ecosystem type. The RR of AM fungal abundance is negative in grasslands and farmlands when the degree of N addition exceeds 33.85 and 67.64 kg N ha⁻¹ yr⁻¹, respectively; however, N addition decreases AM fungal abundance in forests only when the degree of N addition exceeds 871.31 kg N ha⁻¹ yr⁻¹. The above results provide an insight into predicting ecological functions of AM fungal abundance under global changes.

丛枝菌根真菌 (AMF) 在碳循环中发挥关键作用，容易受到气候变化的影响。然而，AM 真菌丰度对气候变化的响应尚不清楚。进行了全球范围的荟萃分析，以研究 AM 真菌丰度对变暖、CO ₂浓度 (eCO ₂ )升高和 N 添加的响应模式。在全球范围内，变暖和 eCO _{2 均}显着刺激 AM 真菌丰度分别增加了 18.6%（95%CI：5.9%–32.8%）和 21.4%（15.1%–28.1%）。然而，AM真菌丰度的响应比（RR）随着变暖程度的增加而降低，而随着eCO ₂程度的增加而增加. 此外，在增温实验中，只要升温超过 4 °C，无论实验持续时间、方法、时期和生态系统类型如何，其对 AM 真菌丰度的影响都会从正面变为负面。N添加对AM真菌丰度的影响为-5.4%（-10.6%–0.2%），并与氮肥输入率和生态系统类型有关。当N添加程度分别超过33.85和67.64 kg N ha ^-1  yr ^{-1 时}，AM真菌丰度的RR在草地和农田中为负值；然而，只有当 N 添加程度超过 871.31 kg N ha ^-1  yr ^-1时，N 添加才会降低森林中 AM 真菌的丰度. 上述结果为预测全球变化下 AM 真菌丰度的生态功能提供了见解。