Department of Cell Biology, University of South Florida, Tampa, FL 33620, USA.
Proc Natl Acad Sci U S A. 2011 Oct 25;108(43):17720-5. doi: 10.1073/pnas.1103824108. Epub 2011 Oct 17.
The global distribution of soil animals and the relationship of below-ground biodiversity to above-ground biodiversity are not well understood. We examined 17,516 environmental 18S rRNA gene sequences representing 20 phyla of soil animals sampled from 11 locations covering a range of biomes and latitudes around the world. No globally cosmopolitan taxa were found and only 14 of 2,259 operational taxonomic units (OTUs) found were common to four or more locations. Half of those were circumpolar and may reflect higher connectivity among circumpolar locations compared with other locations in the study. Even when OTU assembly criteria were relaxed to approximate the family taxonomic level, only 34 OTUs were common to four or more locations. A comparison of our diversity and community structure data to environmental factors suggests that below-ground animal diversity may be inversely related to above-ground biodiversity. Our data suggest that greater soil inorganic N and lower pH could explain the low below-ground biodiversity found at locations of high above-ground biodiversity. Our locations could also be characterized as being dominated by microarthropods or dominated by nematodes. Locations dominated by arthropods were primarily forests with lower soil pH, root biomass, mean annual temperature, low soil inorganic N and higher C:N, litter and moisture compared with nematode-dominated locations, which were mostly grasslands. Overall, our data indicate that small soil animals have distinct biogeographical distributions and provide unique evidence of the link between above-ground and below-ground biodiversity at a global scale.
土壤动物的全球分布以及地下生物多样性与地上生物多样性的关系尚未得到很好的理解。我们研究了来自全球 11 个地点的 17516 个环境 18S rRNA 基因序列，这些地点涵盖了各种生物群落和纬度范围。我们没有发现具有全球普遍性的分类群，在 2259 个操作分类单位（OTUs）中，只有 14 个存在于四个或更多地点。其中一半是环极的，这可能反映了与研究中其他地点相比，环极地区之间的连通性更高。即使放宽 OTU 组装标准以近似于科分类水平，也只有 34 个 OTUs 存在于四个或更多地点。将我们的多样性和群落结构数据与环境因素进行比较表明，地下动物多样性可能与地上生物多样性呈反比。我们的数据表明，较高的土壤无机氮和较低的 pH 值可能解释了高地上生物多样性地点地下生物多样性较低的原因。我们的地点也可以被描述为以微节肢动物为主或以线虫为主。以节肢动物为主的地点主要是森林，其土壤 pH 值、根系生物量、年平均温度、土壤无机氮较低，C:N、凋落物和水分较高，而以线虫为主的地点主要是草原。总体而言，我们的数据表明，小型土壤动物具有独特的生物地理分布，并提供了全球范围内地上和地下生物多样性之间联系的独特证据。
