Wissuwa Janet, Salamon Jörg-Alfred, Frank Thomas
University of Natural Resources and Life Sciences, Department of Integrative Biology and Biodiversity Research, Institute of Zoology, Gregor Mendel Straße 33, A-1180 Vienna, Austria.
Soil Biol Biochem. 2012 Jul;50(6):96-107. doi: 10.1016/j.soilbio.2012.02.025.
Density, diversity and assemblage structure of Mesostigmata (cohorts Gamasina and Uropodina) were investigated in nine grassy arable fallows according to a factorial design with age class (2-3, 6-8, 12-15 years) and plant species (legume: Medicago sativa, herb: Taraxacum officinale, grass: Bromus sterilis) as factors. The response of Mesostigmata to habitat age and plant species was explored because this group belongs to the dominant acarine predators playing a crucial role in soil food webs and being important as biological control agents. To our knowledge, this combination of factors has never been studied before for Mesostigmata. A further rarely applied aspect of the present study is the micro-scale approach investigating the Mesostigmata assemblage of the soil associated with single plants. Four plots were randomly chosen at each fallow in May 2008. At each plot plant roots and the adjacent soil of five randomly selected plant individuals per plant species were dug out with steel cylinders for heat extraction of soil fauna and measurement of environmental parameters. In total, 83 mite taxa were identified, with 50 taxa being new to Austria. GLM analysis revealed a significant effect of plant species on mite density, with significantly more mites in B. sterilis than in T. officinale samples, and M. sativa samples being intermediate. This was in contrast to the assumption that the mite density is highest in M. sativa samples due to the propagation of plant quality effects to higher trophic levels. These results were probably caused by a higher amount of fine roots in grass samples leading to high densities of Collembola, which are preferred prey of predatory mites. Mite density did not significantly differ between the three age classes. A canonical analysis of principal coordinates (CAP) showed that the mite assemblage exhibited a weak yet significant separation between plant species, and a highly significant separation between age classes. Accordingly, different mite assemblages were found for the three age classes, while only few mite species were clearly associated with a single plant species. Finally, canonical correspondence analysis (CCA) revealed that the mite assemblage was best explained by soil organic carbon, total density of Collembola and water content.
按照析因设计，以年龄组（2 - 3年、6 - 8年、12 - 15年）和植物种类（豆科植物：紫花苜蓿、草本植物：蒲公英、禾本科植物：不育雀麦）为因素，对9块草地休耕地中中气门螨类（革螨亚目和尾足螨亚目）的密度、多样性和群落结构进行了调查。对中气门螨类对栖息地年龄和植物种类的反应进行了探究，因为该类群属于优势螨类捕食者，在土壤食物网中起关键作用，并且作为生物防治剂很重要。据我们所知，此前从未针对中气门螨类研究过这种因素组合。本研究另一个很少应用的方面是微观尺度方法，即调查与单株植物相关的土壤中的中气门螨类群落。2008年5月，在每个休耕地随机选取4个样地。在每个样地，用钢筒挖出每个植物种类的5株随机选取植物个体的根系及相邻土壤，用于热提取土壤动物区系并测量环境参数。总共鉴定出83个螨类分类单元，其中50个分类单元对奥地利来说是新的。广义线性模型分析显示，植物种类对螨类密度有显著影响，不育雀麦样本中的螨类比蒲公英样本中的显著更多，紫花苜蓿样本中的螨类数量居中。这与以下假设相反，即由于植物质量效应向更高营养级的传递，紫花苜蓿样本中的螨类密度最高。这些结果可能是由于禾本科植物样本中细根数量较多，导致弹尾目动物密度较高，而弹尾目动物是捕食性螨类的首选猎物。螨类密度在三个年龄组之间没有显著差异。主坐标典型分析（CAP）表明，螨类群落在植物种类之间表现出微弱但显著的分离，在年龄组之间表现出高度显著的分离。因此，在三个年龄组中发现了不同的螨类群落，而只有少数螨类物种与单一植物种类有明显关联。最后，典范对应分析（CCA）表明，螨类群落最好由土壤有机碳、弹尾目动物总密度和含水量来解释。
