Department of Environmental Science, Aarhus University, Roskilde, Denmark.
Research Unit for Comparative Microbiome Analysis (COMI), Helmholtz Zentrum München, Neuherberg, Germany.
Sci Total Environ. 2020 May 15;717:137228. doi: 10.1016/j.scitotenv.2020.137228. Epub 2020 Feb 8.
Soil biodiversity is threatened by intensification of land use. The consequences of different land use on belowground biodiversity remain insufficiently explored for soil protists. Alongside being abundant and extremely diverse in soil, protists provide many ecosystem services: key players in the microbial loop, turnover of organic matter and stimulation of plant growth-promoting rhizobacteria. However, we lack knowledge of effects of site, land use intensity and management on diversity of soil protists. Here we assessed protist communities in four European arable sites with contrasting land use intensities at each site: Lusignan, France; Moskanjci, Slovenia; Castro Verde, Portugal and Scheyern, Germany as well as two grassland sites: Hainich, Germany and Lancaster, UK. Each site has consistent agricultural management history of low and high land use intensities quantified in terms of land use index (LUI). We employed high-throughput sequencing of environmental DNA, targeting the V4 region of the 18S rRNA gene. By assigning the protist composition to trophic groups, we inspected for effects of management, and other biotic and abiotic variables. While overall protist richness was unaffected by LUI within sites, specific trophic groups such as plant pathogens and saprotrophs were affected. Effects on protist biome across land uses and sites were also observed. LUI sensitive taxa were taxonomically diverse in each plot, and their trophic groups responded in specific patterns to specific practices. The most abundant trophic group was phagotrophs (73%), followed by photoautotrophs (16%), plant pathogens (4%), animal parasites (2%) and saprotrophs (1%). Community compositions and factors affecting the structure of individual trophic groups differed between land uses and management systems. The agricultural management selected for distinct protist populations as well as specific functional traits, and the protist community and diversity were indeed affected by site, LUI and management, which indicates the ecological significance of protists in the soil food web.
土壤生物多样性受到土地利用集约化的威胁。由于不同土地利用对土壤原生生物多样性的影响仍未得到充分探索，因此对土壤原生生物多样性的影响仍未得到充分探索。除了在土壤中丰富且非常多样化之外，原生生物还提供了许多生态系统服务：微生物循环中的关键参与者，有机物质的转化和促进植物生长的根际细菌的刺激。然而，我们缺乏有关土地利用强度和管理对土壤原生生物多样性的影响的知识。在这里，我们评估了四个欧洲耕地的原生生物群落，这些耕地在每个地点的土地利用强度都有很大差异：法国的卢西尼亚；斯洛文尼亚的莫斯坎西奇；葡萄牙的卡斯特罗·韦德和德国的谢伊伦以及两个草地地点：德国的海尼希和英国的兰开斯特。每个地点都有一致的农业管理历史，根据土地利用指数（LUI）来量化低土地利用强度和高强度土地利用。我们采用了靶向 18S rRNA 基因 V4 区的环境 DNA 高通量测序。通过将原生生物组成分配到营养组中，我们检查了管理以及其他生物和非生物变量的影响。尽管总体原生生物丰富度不受站点内 LUI 的影响，但特定的营养组，例如植物病原体和腐生物，却受到影响。在土地利用和站点之间，对原生生物生物群系的影响也观察到了。在每个地块中，对 LUI 敏感的类群在分类上都具有多样性，并且它们的营养组以特定的模式对特定的实践做出响应。最丰富的营养组是吞噬组（73％），其次是光合自养生物（16％），植物病原体（4％），动物寄生虫（2％）和腐生物（1％）。群落组成和影响各个营养组结构的因素因土地利用和管理系统而异。农业管理选择了不同的原生生物种群以及特定的功能特征，而原生生物群落和多样性确实受到站点，LUI 和管理的影响，这表明原生生物在土壤食物网中具有生态意义。
