Data from: Fungal community reveals less dispersal limitation and potentially more connected network than that of bacteria in bamboo forest soils

A central aim of current microbial ecology research is to investigate the mechanisms shaping the assembly of soil microbial communities. Despite the importance of bacterial and fungal mediation of carbon cycling in forest ecosystems, knowledge concerning their distribution patterns and underlying mechanisms remains insufficient. Here, soils were sampled from six bamboo forests across the main planting area of Moso bamboo in southern China. The bacterial and fungal diversities were assessed by sequencing 16S rRNA and ITS gene amplicons, respectively, with an Illumina MiSeq. Based on structural equation modeling, dispersal limitation had strongest impact on bacterial beta diversity, while the mean annual precipitation had a smaller impact by directly or indirectly mediating the soil organic carbon density. However, only the mean annual temperature and precipitation played direct roles in fungal beta diversity. Moreover, the co-occurrence network analyses revealed a possibly much higher network connectivity in the fungal network than in the bacteria. With less dispersal limitation, stronger environmental selection, and a potentially more connected network, the fungal community had more important roles in the soil carbon metabolisms in bamboo forests. Fungal beta diversity and the clustering coefficient explained approximately 14.4% and 6.1% of the variation in the carbon metabolic profiles among sites, respectively, but that of bacteria only explained approximately 1.7% and 1.8%, respectively. This study explored soil microbial spatial patterns along with the underlying mechanisms of dispersal limitation, selection, and connectivity of ecological networks, thus providing novel insights into the study of the distinct functional traits of different microbial taxa.

当前微生物生态学（microbial ecology）研究的核心目标之一，是探究调控土壤微生物群落组装的潜在机制。尽管细菌与真菌介导森林生态系统碳循环的过程具有重要生态意义，但目前学界对其分布格局及内在调控机制的认知仍较为匮乏。本研究在中国南方毛竹（Moso bamboo）主种植区的6个竹林样地中采集土壤样本，分别采用Illumina MiSeq测序平台对16S rRNA基因与ITS基因扩增子进行测序，以此评估细菌与真菌的群落多样性。基于结构方程模型（structural equation modeling）分析，扩散限制对细菌β多样性（beta diversity）的调控作用最强；年平均降水量则通过直接或间接介导土壤有机碳密度，对细菌β多样性（beta diversity）产生较弱的影响，而仅年平均气温与年平均降水量对真菌β多样性（beta diversity）具有直接调控作用。此外，共现网络（co-occurrence network）分析结果显示，真菌群落的网络连通性显著高于细菌群落。相较于细菌群落，真菌群落具有更低的扩散限制、更强的环境筛选作用以及更紧密的网络连通性，因此在竹林土壤碳代谢过程中发挥更为关键的生态功能。真菌β多样性（beta diversity）与聚类系数（clustering coefficient）分别解释了样点间碳代谢特征约14.4%与6.1%的变异；而细菌β多样性（beta diversity）与聚类系数（clustering coefficient）仅分别解释了约1.7%与1.8%的变异。本研究探明了土壤微生物的空间分布格局，并揭示了扩散限制、环境筛选及生态网络连通性等内在调控机制，为解析不同微生物类群的独特功能性状提供了全新的研究视角。