Drought alters the structure and functional traits of soil nematodes

We evaluated the impact of drought on the abundance of nematode functional groups within their community and the body size of communities and distinct key nematode species. For that we collected data on soil nematode abundance from published studies that documented the community structure of nematodes exposed to a gradient of water availability in mainland China. Because bacterivorous and fungivorous nematodes grouped in colonizer-persister (cp)-2 guilds are more tolerant to stress (e.g., pollution) than other functional guilds, we selected five abundant and widespread genera as model organisms (Cephalobus, Eucephalobus, Acrobeloides, Aphelenchoides and Aphelenchus). We correlated their relative abundance with soil moisture content and mean annual precipitation to assess their response to drought. Furthermore, we carried out a controlled microcosm experiment to test the influence of drought stress on nematode community structure, identify the winners and losers, and examine the contributing factors including pre-drought abundance, pre-drought body size, generation time, and body size reduction rate. We evaluated the trait-based mechanisms of survival in drought-tolerant species in a petri dish experiment by investigating the survival rate and body size variation of the bacterivore Acrobeloides and the model bacterivore C. elegans across a drought stress gradient.

本研究旨在评估干旱对土壤线虫功能群在群落中的丰度和群落及特定关键线虫物种体型的影响。为此，我们从在中国大陆不同水分可用性梯度下暴露的线虫群落结构的研究文献中收集了土壤线虫丰度数据。鉴于捕食细菌和真菌的线虫属于殖民者-持久者（cp）-2功能群，相较于其他功能群，它们对压力（例如，污染）具有更强的耐受性，因此我们选取了五种丰度较高且分布广泛的属作为模型生物（头虫属、欧头虫属、锐形虫属、根结线虫属和根结线虫属）。我们将它们的相对丰度与土壤水分含量和年平均降水量相关联，以评估其对干旱的反应。此外，我们进行了一项控制微宇宙实验，以测试干旱压力对线虫群落结构的影响，识别赢家和输家，并检查包括干旱前丰度、干旱前体型、世代时间和体型减少率在内的贡献因素。通过调查在干旱压力梯度下细菌食性锐形虫和模式细菌食性秀丽隐杆线虫的存活率和体型变化，我们在培养皿实验中评估了耐旱物种基于特性的生存机制。