Weißbecker Christina, Wubet Tesfaye, Lentendu Guillaume, Kühn Peter, Scholten Thomas, Bruelheide Helge, Buscot François
Department of Soil Ecology, Helmholtz-Centre for Environmental Research - UFZ, Halle, Germany.
Institute of Biology, Leipzig University, Leipzig, Germany.
Front Microbiol. 2018 Oct 9;9:2312. doi: 10.3389/fmicb.2018.02312. eCollection 2018.
Deconvoluting the relative contributions made by specific biotic and abiotic drivers to soil fungal community compositions facilitates predictions about the functional responses of ecosystems to environmental changes, such as losses of plant diversity, but it is hindered by the complex interactions involved. Experimental assembly of tree species allows separation of the respective effects of plant community composition (biotic components) and soil properties (abiotic components), enabling much greater statistical power than can be achieved in observational studies. We therefore analyzed these contributions by assessing, via pyrotag sequencing of the internal transcribed spacer (ITS2) rDNA region, fungal communities in young subtropical forest plots included in a large experiment on the effects of tree species richness. Spatial variables and soil properties were the main drivers of soil fungal alpha and beta-diversity, implying strong early-stage environmental filtering and dispersal limitation. Tree related variables, such as tree community composition, significantly affected arbuscular mycorrhizal and pathogen fungal community structure, while differences in tree host species and host abundance affected ectomycorrhizal fungal community composition. At this early stage of the experiment, only a limited amount of carbon inputs (rhizodeposits and leaf litter) was being provided to the ecosystem due to the size of the tree saplings, and persisting legacy effects were observed. We thus expect to find increasing tree related effects on fungal community composition as forest development proceeds.
解析特定生物和非生物驱动因素对土壤真菌群落组成的相对贡献，有助于预测生态系统对环境变化（如植物多样性丧失）的功能响应，但这受到其中复杂相互作用的阻碍。通过实验组装树种，可以分离植物群落组成（生物成分）和土壤性质（非生物成分）的各自影响，从而获得比观测研究更大的统计效力。因此，我们通过对参与一项关于树种丰富度影响的大型实验中的亚热带幼龄森林样地内的真菌群落进行内转录间隔区（ITS2）核糖体DNA区域的焦磷酸测序评估，来分析这些贡献。空间变量和土壤性质是土壤真菌α和β多样性的主要驱动因素，这意味着早期存在强烈的环境过滤和扩散限制。与树木相关的变量，如树木群落组成，显著影响丛枝菌根真菌和病原菌真菌群落结构，而树木宿主物种和宿主丰度的差异影响外生菌根真菌群落组成。在实验的这个早期阶段，由于树苗的大小，只有有限量的碳输入（根际沉积物和落叶）被提供给生态系统，并且观察到了持续的遗留效应。因此，我们预计随着森林的发展，会发现与树木相关的因素对真菌群落组成的影响不断增加。
