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Title: [Environmental selection and dispersal limitation drive the assemblage of bacterial community in temperate forest soils].
Author: Ma ZZ, Qiao SS, Cao MW, Zhou YN, Liu JX, Jia T, Li C, Chai BF.
Journal: Ying Yong Sheng Tai Xue Bao; 2018 Apr; 29(4):1179-1189. PubMed ID: 29726227.
Abstract:
Environmental selection and dispersal limitation are two basic processes underlying community assembly. The relative importance of those two processes differs across scales, community identities, and community types. The processes responsible for structuring microbial communities in soil of temperate subalpine forest are poorly understood. Here, we investigated the relationship between soil bacterial community structure and environmental factors, and quantified the relative role of edaphic factors, vegetation, and spatial variables in shaping the structure of six soil bacterial communities (LpMC1, LpMC2, PwMC, PmMC, PtMC, and BMC) in five forest types including Larix principis-rupprechtii, Picea wilsonii, Picea meyeri, Pinus tabulaeformis, and Betula platyphylla in Pangquangou Nature Reserve by using PCR-DGGE technology. Our results showed that the structure and biodiversity of bacterial communities were significantly different among six communities. The biodiversity of bacterial community were higher in LpMC2 and PtMC, lowest in PmMC, and highest in LpMC1. Soil environmental factors, such as pH, soil water content, total carbon, total nitrogen, soil organic matter, available phosphorous, and soil enzymes, were significantly correlated with biodiversity and structure of soil bacterial community. The beta diversity of bacterial communities were significantly correlated with geographic distance, indicating the influence of dispersal limitation on the structure of bacterial community. The order of driving force on the structure of bacterial community was edaphic factors (0.27), spatial factor (0.19) and vegetation (0.15) in six samples. Using regional soil microbes from 10 samples around reserve as source community, results from the microcosm experiments showed that the edaphic factors were the predominant driving factors (0.35) on structure of artificial dispersal bacterial community, while the high diversity of source microbial community affected the structure of microcosm soil. In summary, at local scale, environmental selection predominantly determined the structural and biodiversity of soil bacterial communities in temperate subalpine forest, while dispersal limitation played a significant role. Such a result indicated that deterministic processes and stochastic processes played important roles in shaping the structure of soil bacterial community at local scale, with the former having the leading role. The composition of dispersal soil bacteria community was source-dependent but also modulated by local environmental selection. 环境选择和扩散限制是生态系统中生物群落构建的两个基本过程,而两者相对作用的大小因研究尺度、群落属性和类型等有所不同.目前对温带亚高山森林土壤微生物群落构建的驱动因子和机制尚缺乏了解.本文利用PCR-DGGE技术研究庞泉沟自然保护区内5种典型森林包括华北落叶松林、青杄林、白杄林、油松林以及桦树林的6个森林土壤细菌群落(LpMC1、LpMC2、PwMC、PmMC、PtMC、BMC)的结构特征及其影响因素,分析细菌群落结构与环境因子的相关性,以及土壤因子、植被和空间因素对细菌群落结构的影响.结果表明: 研究区各样地土壤细菌群落的结构和生物多样性具有显著差异,低海拔落叶松和油松土壤细菌群落多样性较高(20条带),白杄林土壤细菌群落(13条带)多样性最低,高海拔落叶松土壤细菌群落多样性最高;土壤环境因子,如pH、土壤含水量、总碳、总氮、土壤有机质、速效磷以及土壤酶活性与土壤细菌群落多样性和结构显著相关;样地土壤细菌群落的beta多样性与群落的空间距离呈显著相关,表明扩散限制对群落结构具有一定的影响;方差分解分析结果显示,6个样地细菌群落结构的驱动因素大小依次为土壤因子(0.27)、空间因素(0.19)和植被(0.15);将区域土壤微生物作为“源群落”,微宇宙试验结果显示,土壤因子是细菌群落结构形成的主要驱动力(0.35),同时源群落丰富的物种多样性对微宇宙土壤细菌群落结构具有显著影响.总之,在局域尺度下,环境选择对温带森林土壤细菌群落结构动态和多样性发挥主导作用,地理距离对群落结构具有显著影响,即确定性过程和随机过程共同决定局域森林土壤细菌群落结构,前者占主导地位.对于土壤细菌群落而言,扩散群落的组成和结构受到源群落的多样性特征和环境因子的双重影响.

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