Wu Shu-Hong, Huang Bing-Hong, Gao Jian, Wang Siqi, Liao Pei-Chun
School of Nature Conservation, Beijing Forestry University, Beijing, China.
Department of Life Science, National Taiwan Normal University, Taipei, Taiwan.
PeerJ. 2019 Jan 11;7:e6147. doi: 10.7717/peerj.6147. eCollection 2019.
Grassland afforestation dramatically affects the abiotic, biotic, and ecological function properties of the original ecosystems. Interference from afforestation might disrupt the stasis of soil physicochemical properties and the dynamic balance of microbiota. Some studies have suggested low sensitivity of soil properties and bacterial community to afforestation, but the apparent lack of a significant relationship is probably due to the confounding effects of the generalist habitat and rare bacterial communities. In this study, soil chemical and prokaryotic properties in a 30-year-old Mongolia pine ( var. Litv.) afforested region and adjacent grassland in Inner Mongolia were classified and quantified. Our results indicate that the high richness of rare microbes accounts for the alpha-diversity of the soil microbiome. Few OTUs of generalist (core bacteria) and habitat-specialist bacteria are present. However, the high abundance of this small number of OTUs governs the beta-diversity of the grassland and afforested land bacterial communities. Afforestation has changed the soil chemical properties, thus indirectly affecting the soil bacterial composition rather than richness. The contents of soil P, Ca, and Fe account for differentially abundant OTUs such as Planctomycetes and subsequent changes in the ecologically functional potential of soil bacterial communities due to grassland afforestation. We conclude that grassland afforestation has changed the chemical properties and composition of the soil and ecological functions of the soil bacterial community and that these effects of afforestation on the microbiome have been modulated by changes in soil chemical properties.
草原造林对原始生态系统的非生物、生物及生态功能特性产生了巨大影响。造林干扰可能会破坏土壤理化性质的稳态以及微生物群的动态平衡。一些研究表明土壤性质和细菌群落对造林的敏感性较低，但明显缺乏显著关系可能是由于泛生境和稀有细菌群落的混杂效应。在本研究中，对内蒙古一个有着30年历史的樟子松（变种Litv.）造林区域及邻近草原的土壤化学和原核生物特性进行了分类和量化。我们的结果表明，稀有微生物的高丰富度构成了土壤微生物组的α多样性。泛生菌（核心细菌）和生境特异性细菌的操作分类单元很少。然而，这少数操作分类单元的高丰度决定了草原和造林地细菌群落的β多样性。造林改变了土壤化学性质，从而间接影响土壤细菌组成而非丰富度。土壤磷、钙和铁的含量导致了诸如浮霉菌门等差异丰富的操作分类单元以及草原造林后土壤细菌群落生态功能潜力的后续变化。我们得出结论，草原造林改变了土壤的化学性质、组成以及土壤细菌群落的生态功能，并且造林对微生物组这些影响已因土壤化学性质的变化而受到调节。
