Fungal communities play important roles in terrestrial ecosystem functioning. Unraveling the relative importance of stochastic versus deterministic processes in shaping biogeographic patterns of fungal communities has long been a challenge in microbial ecology, owing to high biodiversity and difficulties in identifying fungal taxa. Using a unique anthropogenic system of geographically isolated paddy ‘islands’, we collected 198 soil samples with a spatially explicit design to examine how ecological processes shaped fungal biogeographic patterns. Fungal community structure showed scale-dependent distance-decay relationships. Stochastic processes (dispersal and drift) contributed more to community assembly than deterministic processes (selection) at the local scale, which was largely attributed to drift. In contrast, deterministic processes contributed more to community assembly than stochastic processes at the regional scale, with soil dissolved organic carbon being the most important measured factor. Collectively, scale dependence of fungal biogeographical patterns in paddy soils is influenced by differential contribution of deterministic and stochastic processes.

真菌群落在陆地生态系统功能中发挥重要作用。由于存在较高的生物多样性和识别真菌类群的困难，在微生物生态学中，长期以来，阐明随机过程和确定性过程在塑造真菌群落生物地理模式方面的相对重要性一直是一个挑战。我们使用独特的人为地理系统来分离稻谷，我们以空间明确的设计收集了198个土壤样本，以研究生态过程如何塑造真菌的生物地理格局。真菌群落结构显示尺度依赖距离衰减关系。随机过程（分散和漂移）对社区聚集的贡献大于局部规模上的确定性过程（选择），这在很大程度上归因于漂移。相比之下，确定性过程对社区聚集的贡献大于区域规模上的随机过程，其中土壤溶解的有机碳是最重要的衡量因素。总的来说，稻田土壤中真菌生物地理格局的尺度依赖性受确定性过程和随机过程的不同贡献的影响。