Montecchia Marcela S, Tosi Micaela, Soria Marcelo A, Vogrig Jimena A, Sydorenko Oksana, Correa Olga S
Instituto de Investigaciones en Biociencias Agrícolas y Ambientales (INBA-CONICET/UBA), Cátedra de Microbiología Agrícola, Facultad de Agronomía, Universidad de Buenos Aires, Ciudad Autónoma de Buenos Aires, Argentina.
PLoS One. 2015 Mar 20;10(3):e0119426. doi: 10.1371/journal.pone.0119426. eCollection 2015.
The Southern Andean Yungas in Northwest Argentina constitute one of the main biodiversity hotspots in the world. Considerable changes in land use have taken place in this ecoregion, predominantly related to forest conversion to croplands, inducing losses in above-ground biodiversity and with potential impact on soil microbial communities. In this study, we used high-throughput pyrosequencing of the 16S ribosomal RNA gene to assess whether land-use change and time under agriculture affect the composition and diversity of soil bacterial communities. We selected two areas dedicated to sugarcane and soybean production, comprising both short- and long-term agricultural sites, and used the adjacent native forest soils as a reference. Land-use change altered the composition of bacterial communities, with differences between productive areas despite the similarities between both forests. At the phylum level, only Verrucomicrobia and Firmicutes changed in abundance after deforestation for sugarcane and soybean cropping, respectively. In cultivated soils, Verrucomicrobia decreased sharply (~80%), while Firmicutes were more abundant. Despite the fact that local diversity was increased in sugarcane systems and was not altered by soybean cropping, phylogenetic beta diversity declined along both chronosequences, evidencing a homogenization of soil bacterial communities over time. In spite of the detected alteration in composition and diversity, we found a core microbiome resistant to the disturbances caused by the conversion of forests to cultivated lands and few or none exclusive OTUs for each land-use type. The overall changes in the relative abundance of copiotrophic and oligotrophic taxa may have an impact in soil ecosystem functionality. However, communities with many taxa in common may also share many functional attributes, allowing to maintain at least some soil ecosystem services after forest conversion to croplands.
阿根廷西北部的南安第斯永加斯地区是世界主要的生物多样性热点地区之一。该生态区发生了显著的土地利用变化，主要与森林转变为农田有关，导致地上生物多样性丧失，并对土壤微生物群落产生潜在影响。在本研究中，我们使用16S核糖体RNA基因的高通量焦磷酸测序来评估土地利用变化和农业种植时间是否会影响土壤细菌群落的组成和多样性。我们选择了两个专门用于甘蔗和大豆生产的区域，包括短期和长期农业用地，并将相邻的原生森林土壤作为参照。土地利用变化改变了细菌群落的组成，尽管两片森林相似，但生产区之间存在差异。在门水平上，分别在砍伐森林用于种植甘蔗和大豆后，疣微菌门和厚壁菌门的丰度发生了变化。在耕种土壤中，疣微菌门急剧减少（约80%），而厚壁菌门更为丰富。尽管甘蔗种植系统中的局部多样性增加，大豆种植未改变局部多样性，但系统发育β多样性在两个时间序列上均下降，表明随着时间推移土壤细菌群落趋于同质化。尽管检测到组成和多样性发生了变化，但我们发现了一个核心微生物组，它对森林转变为耕地所造成的干扰具有抗性，并且每种土地利用类型几乎没有或没有专属的操作分类单元。富营养型和贫营养型类群相对丰度的总体变化可能会对土壤生态系统功能产生影响。然而，具有许多共同类群的群落也可能共享许多功能属性，从而在森林转变为农田后至少维持一些土壤生态系统服务。
