扩散主导但土壤变异选择：河口沉积物真菌空间差异下的一致生态过程

摘要(中文译文)

河口生态系统具有强烈的环境梯度和复杂的生态过程。本研究沿跨越中国北部（NCS）、东部（ECS）和南部（SCS）沿海地区的纬度梯度，研究了我国河口潮间带真菌的空间格局、生态驱动因素及群落构建过程。群落α多样性在NCS和SCS高于ECS，而物种丰富度在ECS高于NCS和SCS。群落β多样性随地理距离显著增加，硝酸盐、有机碳和铁离子被确定为关键环境驱动因素。基于生态位宽度（Levins指数）和物种分类的生态位分析显示，泛化种（32.92%）与特化种（45.55%）的比例存在显著差异，且NCS真菌群落的平均生态位宽度显著高于ECS和SCS，反映出最低的环境敏感性。中性模型分析表明，扩散限制是塑造真菌群落构建的主要过程，其影响从高纬度向低纬度地区逐渐增强。此外，所有真菌共现网络均表现出较弱的模块性，凸显了真菌类群之间分散的、非模块化的相互作用模式。这些发现为理解潮间带真菌群落的宏观生态格局及其对生态系统稳定性的意义提供了重要见解。

Abstract

Estuarine ecosystems exhibit strong environmental gradients and complex ecological processes. Here, we investigated the spatial patterns, ecological drivers and assembly processes of fungi across China's estuarine intertidal zones along a latitudinal gradient spanning the northern (NCS), eastern (ECS) and southern (SCS) coastal regions. The community α-diversity was higher in NCS and SCS than in ECS, whereas species richness was higher in ECS than in NCS and SCS. Community β-diversity increased significantly with geographic distance, with nitrate, organic carbon and ferric iron identified as the key environmental drivers. Niche analysis based on niche breadth (Levins' index) and species classification revealed a significant difference between the proportions of generalist species (32.92%) and specialist species (45.55%), and the mean niche breadth of fungal communities in NCS was significantly higher than that in ECS and SCS, reflecting the lowest environmental sensitivity. Neutral model analysis suggested that dispersal limitation was the predominant process shaping fungal community assembly, with its influence increasing from high- to low-latitude regions. Moreover, all fungal co-occurrence networks displayed weak modularity, highlighting a dispersed, non-modular interaction pattern among fungal taxa. These findings provide important insights into the macroecological patterns of intertidal fungal communities and their implications for ecosystem stability.

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