St John Mark G, Wall Diana H, Hunt H William
Natural Resource Ecology Laboratory, Colorado State University, Fort Collins 80523-1499, USA.
Ecology. 2006 May;87(5):1314-24. doi: 10.1890/0012-9658(2006)87[1314:asmasb]2.0.co;2.
Associations between plants and animals in aboveground communities are often predictable and specific. This has been exploited for the purposes of estimating the diversity of animal species based on the diversity of plant species. The introduction of invasive alien plants into an ecosystem can result in dramatic changes in both the native plant and animal assemblages. Few data exist at the species level to determine whether belowground animal assemblages share the same degree of association to plants. The hypotheses that soil mites (Acari) form assemblages specifically associated with different native grass species in an unmanipulated natural ecosystem and that invasive alien grasses will impact soil mite assemblage composition in this setting were tested. Soil mites sampled beneath five native and two invasive alien species of grasses at the Konza Prairie Biological Station, Kansas, USA, were similarly abundant, species rich, diverse, and taxonomically distinct. No mite species had affinities for a specific grass species. There was no evidence from analysis of similarity, canonical correspondence analysis, or a nonparametric assemblage analysis that the assemblage composition of soil mites was specific to grass species. Results suggest that soil mite assemblages were more related to characteristics of the plant assemblage as a whole or prevailing soil conditions. The most recent invasive alien grass did not support a successionally younger mite fauna, based on the ratio of mesostigmatid to oribatid mites, and neither of the two invasive grasses influenced mite assemblage structure, possibly because they had not yet substantially altered the soil environment. Our results suggest that extrapolations of soil mite diversity based on assumptions of plant specificity would be invalid.
地上群落中植物与动物之间的关联通常是可预测且特定的。这一点已被用于基于植物物种的多样性来估计动物物种的多样性。将外来入侵植物引入生态系统会导致本地植物和动物群落发生巨大变化。在物种层面，几乎没有数据可用于确定地下动物群落与植物的关联程度是否相同。我们检验了以下假设：在未受人为干扰的自然生态系统中，土壤螨类（蜱螨亚纲）形成了与不同本地禾本科物种特异性相关的群落，并且在这种情况下外来入侵禾本科植物会影响土壤螨类群落的组成。在美国堪萨斯州孔扎草原生物站，对五种本地禾本科植物和两种外来入侵禾本科植物地下的土壤螨类进行采样，发现它们在数量、物种丰富度、多样性和分类上同样具有明显差异。没有螨类物种对特定的禾本科植物有偏好。相似性分析、典范对应分析或非参数群落分析均未提供证据表明土壤螨类群落组成对禾本科植物具有特异性。结果表明，土壤螨类群落与整个植物群落的特征或主要土壤条件的关系更为密切。基于中气门螨类与甲螨的比例，最新入侵的外来禾本科植物并未支持一个演替上更年轻的螨类动物区系，并且这两种入侵禾本科植物均未影响螨类群落结构，可能是因为它们尚未对土壤环境产生实质性改变。我们的结果表明，基于植物特异性假设推断土壤螨类多样性是无效的。
