Termite mounds are an important habitat for an enormous diversity of microorganisms. However, the microbial community assembly processes in termite mounds remain unresolved, which impeded our ability to predict the biological functions of these mound-associated microbiota under the global changes. Here we conducted a large-scale investigation in northern Australia to explore biogeographical patterns of microbial community in termite mounds and identify the role of deterministic and stochastic processes in microbial community assembly. Microbial communities in termite mounds exhibited a significant distance-decay pattern, and fungi had a stronger distance-decay relationship than bacteria. The neutral community model and normalized stochasticity ratio index (NST) revealed that the deterministic selection, rather than stochastic forces, predominated the microbial community assembly in termite mounds. Deterministic processes exhibited a significantly weaker impact on bacteria (NST = 45.23%) than on fungi (NST = 33.72%), likely due to the wider habitat niche breadth and higher potential migration rate of bacteria. Random forest model further demonstrated that mean annual temperature was the most important predictor of both bacterial and fungal profiles in termite mounds. These findings improved our understanding of spatial patterns and processes of microbiome in termite mounds, which is critical to decipher the role of termite mounds associated microbes in regulating ecosystem multifunctionality.

白蚁丘是微生物多样性的重要栖息地。然而，白蚁丘中微生物群落的组装过程仍未解决，这阻碍了我们预测在全球变化下这些丘陵相关微生物群的生物学功能的能力。在这里，我们在澳大利亚北部进行了大规模调查，以探索白蚁丘中微生物群落的生物地理模式，并确定确定性和随机过程在微生物群落装配中的作用。白蚁丘中的微生物群落表现出明显的距离-衰减模式，并且真菌具有比细菌更强的距离-衰减关系。中性社区模型和归一化随机率指数（NST）表明，确定性选择而不是随机作用力在白蚁丘中占主导地位。确定性过程对细菌的影响（NST = 45.23％）比对真菌的影响（NST = 33.72％）明显弱于真菌（NST = 33.72％），这可能是由于栖息地的利基宽度更广以及潜在的细菌迁移率更高。随机森林模型进一步证明，年平均温度是白蚁丘中细菌和真菌分布的最重要预测指标。这些发现增进了我们对白蚁丘中微生物群的空间格局和过程的理解，这对于破译白蚁丘相关微生物在调节生态系统多功能方面的作用至关重要。