Institute for Soil Sciences and Agricultural Chemistry, Centre for Agricultural Research, Hungarian Academy of Sciences, Budapest, Hungary.
Department of Biometrics and Agricultural Informatics, Faculty of Horticultural Science, Szent István University, Budapest, Hungary.
PLoS One. 2019 Jul 18;14(7):e0219975. doi: 10.1371/journal.pone.0219975. eCollection 2019.
Soil moisture is one of the most important factors affecting soil biota. In arid and semi-arid ecosystems, soil mesofauna is adapted to temporary drought events, but, until now, we have had a limited understanding of the impacts of the different magnitudes and frequencies of drought predicted to occur according to future climate change scenarios. The present study focuses on how springtails and mites respond to simulated repeated drought events of different magnitudes in a field experiment in a Hungarian semi-arid sand steppe. Changes in soil arthropod activities were monitored with soil trapping over two years in a sandy soil. In the first year (2014), we applied an extreme drought pretreatment, and in the consecutive year, we applied less devastating treatments (severe drought, moderate drought, water addition) to these sites. In the first year, the extreme drought pretreatment tended to have a negative effect (either significantly or not significantly) on the capture of all Collembola groups, whereas all mite groups increased in activity density. However, in the consecutive year, between the extreme drought and control treatments, we only detected differences in soil microbial biomass. In the cases of severe drought, moderate drought and water addition, we did not find considerable changes across the microarthropods, except in the case of epedaphic Collembola. In the cases of the water addition and drought treatments, the duration and timing of the manipulation seemed to be more important for soil mesofauna than their severity (i.e., the level of soil moisture decrease). We suggest that in these extreme habitats, soil mesofauna are able to survive extreme conditions, and their populations recover rapidly, but they may not be able to cope with very long drought periods.
土壤湿度是影响土壤生物群最重要的因素之一。在干旱和半干旱生态系统中，土壤中型动物适应于暂时的干旱事件，但直到现在，我们对未来气候变化情景预测的不同规模和频率的干旱对其产生的影响的了解还很有限。本研究主要关注跳虫和螨虫在匈牙利半干旱沙质草原的田间实验中，对不同规模模拟重复干旱事件的反应。通过在沙质土壤中进行两年的土壤诱捕监测，研究了土壤节肢动物活动的变化。在第一年（2014 年），我们进行了极端干旱预处理，第二年，我们对这些地点进行了更具破坏性的处理（严重干旱、中度干旱、加水）。在第一年，极端干旱预处理对所有跳虫类群的捕获量都有负面影响（无论是显著的还是不显著的），而所有螨类群的活动密度都增加了。然而，在第二年，在极端干旱和对照处理之间，我们只检测到土壤微生物生物量的差异。在严重干旱、中度干旱和加水处理的情况下，我们没有发现微型节肢动物有明显的变化，除了表土跳虫类群外。在加水和干旱处理的情况下，处理的持续时间和时间似乎比其严重程度（即土壤湿度降低水平）对土壤中型动物更为重要。我们认为，在这些极端生境中，土壤中型动物能够在极端条件下生存，并且它们的种群迅速恢复，但它们可能无法应对非常长的干旱期。
