Response of Collembola and Acari communities to summer flooding in a grassland plant diversity experiment

Flooding frequency is predicted to increase during the next decades in Europe. Therefore, it is important to understand how short-term disturbance events affect soil biota providing essential ecosystem functions and uncover factors modulating their response such as plant community composition. Here we report on the response of soil microarthropod communities (Collembola and Acari) to a severe summer flood in 2013, which affected major parts of central Europe. Collembola and Acari density and Collembola and Oribatida richness were strongly affected by the flood, but they recovered within three months. Effects of plant community composition on soil microarthropods disappeared after the flood, presumably due to homogenization of the field, but the effects of plant community were in a stage of being reasserted three months after the flood. Widespread, surface living and generalistic microarthropod species recolonized the field quickly. Prostigmata and Oribatida were more resilient or recovered to flooding than Astigmata and Gamasida. Long-term impacts, however, remain unknown and deserve further investigation.

预计未来数十年间，欧洲的洪涝灾害发生频率将呈上升趋势。因此，厘清短期扰动事件如何影响发挥核心生态系统功能的土壤生物群落，并揭示调控其响应的相关因素（如植物群落组成），具有重要的科学意义。本研究针对2013年一场波及中欧大部分区域的夏季特大洪涝，探究了土壤微型节肢动物群落（弹尾纲Collembola、蜱螨亚纲Acari）的响应特征。研究结果表明，弹尾纲与蜱螨亚纲的个体密度、以及弹尾纲和甲螨亚目（Oribatida）的类群丰富度均受到此次洪涝的显著影响，但所有类群均在三个月内完成了群落恢复。洪涝发生后，植物群落组成对土壤微型节肢动物的调控效应一度消失，推测原因为试验样地的生境发生均一化；但在洪涝过后三个月，植物群落的调控效应已呈现出重新显现的态势。广布性、地表栖息且泛化型的微型节肢动物物种能够快速完成样地重新定殖。前气门亚目（Prostigmata）与甲螨亚目（Oribatida）对洪涝的耐受恢复能力显著强于无气门亚目（Astigmata）与革螨亚目（Gamasida）。不过，此次洪涝对土壤微型节肢动物群落的长期影响仍未明确，有待开展进一步研究加以探明。