Understanding biogeographical patterns and underlying processes of belowground community assembly is crucial for predicting soil functions and their responses to global environmental change. However, little is known about potential differences of belowground community assembly among bacteria, fungi, protists and soil animals, particularly for alpine ecosystems. Based on the combination of large-scale field sampling, high-throughput marker-gene sequencing and multiple statistical analyses, we explored patterns and drivers of belowground community assembly in alpine grasslands on the Tibetan Plateau. Our results revealed that the distance–decay rates varied among trophic levels, with organisms of higher trophic level having weaker distance–decay pattern. The spatial and environmental variables explained limited variations of belowground communities. By contrast, the stochastic processes, mainly consisting of dispersal limitation and drift, played a primary role in regulating belowground community assembly. Moreover, the relative importance of stochastic processes varied among trophic levels, with the role of dispersal limitation weakening whereas that of drift enhancing in the order of bacteria, fungi, protists and soil animals. These findings advance our understanding of patterns and mechanisms driving belowground community assembly in alpine ecosystems and provide a reference basis for predicting the dynamics of ecosystem functions under changing environment.

中文翻译：

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随机过程调控青藏高原高寒草原地下群落集结

了解地下群落组装的生物地理模式和潜在过程对于预测土壤功能及其对全球环境变化的响应至关重要。然而，人们对细菌、真菌、原生生物和土壤动物之间地下群落组装的潜在差异知之甚少，特别是对于高山生态系统而言。基于大规模野外采样、高通量标记基因测序和多重统计分析相结合，我们探索了青藏高原高寒草原地下群落聚集的模式和驱动因素。我们的研究结果表明，不同营养水平的距离衰减率各不相同，营养水平较高的生物具有较弱的距离衰减模式。空间和环境变量解释了地下社区的有限变化。相比之下，主要由扩散限制和漂移组成的随机过程在调节地下群落组装中起主要作用。此外，随机过程的相对重要性在营养水平上有所不同，扩散限制的作用减弱，而漂移的作用增强，细菌、真菌、原生生物和土壤动物的顺序。这些发现促进了我们对驱动高山生态系统地下群落聚集的模式和机制的理解，并为预测变化环境下生态系统功能的动态提供了参考依据。随机过程的相对重要性在营养水平上有所不同，扩散限制的作用减弱，而漂移的作用增强，细菌、真菌、原生生物和土壤动物的顺序。这些发现促进了我们对驱动高山生态系统地下群落聚集的模式和机制的理解，并为预测变化环境下生态系统功能的动态提供了参考依据。随机过程的相对重要性在营养水平上有所不同，扩散限制的作用减弱，而漂移的作用增强，细菌、真菌、原生生物和土壤动物的顺序。这些发现促进了我们对驱动高山生态系统地下群落聚集的模式和机制的理解，并为预测变化环境下生态系统功能的动态提供了参考依据。