Data supporting: Combined heat and drought affect the abundance, composition, and diversity of subalpine surface-active soil arthropod communities

This dataset supports a field study of the effects of soil heating and drought manipulations <i>in situ</i> on the soil arthropod community during the growing season in subalpine grassy herbfields in NSW, Australia.<b>Abstract</b>Alpine and subalpine ecosystems are predicted to have increased temperature and altered seasonal rainfall and snow cover duration as climate change progresses, potentially changing the communities of these ecosystems. Soil arthropods facilitate key environmental processes that determine ecosystem function and stability; however, little is known about how warming and drought conditions impact soil arthropod communities in the field. This study aimed to assess the effects of soil warming and drought conditions on the abundance and diversity of soil arthropod communities. Climate-controlled shelters manipulated soil temperature and incoming precipitation in a factorial experiment (FutureClim) in a subalpine grassy herbfield in Australia. Surface-active arthropods were sampled from climate-controlled shelters using pitfall traps in January, March, and April 2023, and were identified to order. Abundance, diversity, and community composition changed significantly across the sampling period. Diversity was lowest in all warming and drought treatments in April relative to control, while community composition was significantly driven by temperature and moisture but also was highly variable across the site. The effects of warming and drought on abundance differed substantially between arthropod taxa, with opposing effects on mesofauna and macrofauna. Two Collembola orders, which comprised a large proportion of the arthropod community, were more abundant in heated shelters during the cooler months. In contrast, Hymenoptera (mostly driven by the dominant alpine ant <i>Iridomyrmex alpinus</i>), Hemiptera, and Diptera were more abundant in drought and heat-drought conditions, but larvae were scarce in droughted treatments. Collectively, this study suggests that abundance, composition, and possibly diversity of surface-active mesofauna and macrofauna will likely change in future. Focus on phenological shifts of communities over both short and long timescales, coupled with vegetation and soil changes, is needed to better understand potential ecological changes associated with soil warming and drying.

本数据集支持一项野外研究，该研究针对澳大利亚新南威尔士州（New South Wales, NSW）的亚高山草本草甸，探究生长季内原位（in situ）土壤增温与干旱调控对土壤节肢动物群落的影响。**摘要**随着气候变化加剧，高山与亚高山生态系统预计将面临气温升高、季节性降雨格局改变以及积雪覆盖时长变化，进而可能引发这些生态系统内群落结构的改变。土壤节肢动物驱动着决定生态系统功能与稳定性的关键环境过程，但目前学界对野外增温与干旱条件如何影响土壤节肢动物群落的认知仍较为匮乏。本研究旨在评估土壤增温与干旱条件对土壤节肢动物群落丰度及多样性的影响。研究采用气候控制舱对土壤温度与大气降水输入量进行调控，于澳大利亚亚高山草本草甸中开展析因实验（FutureClim）。2023年1月、3月与4月，研究人员通过陷捕器（pitfall trap）从气候控制舱中采集地表活动型节肢动物，并将其鉴定至目级阶元。采样周期内，节肢动物的丰度、多样性及群落组成均发生了显著变化。相较于对照组，4月所有增温与干旱处理组的多样性均降至最低；而群落组成则显著受温度与土壤湿度调控，同时在样地内呈现出较高的空间异质性。增温与干旱对节肢动物丰度的影响因类群而异，对中型土壤动物（mesofauna）与大型土壤动物（macrofauna）的作用甚至截然相反。占节肢动物群落较大比例的两类弹尾纲（Collembola）类群，在较凉爽的月份于增温舱中丰度更高。与之相反，膜翅目（Hymenoptera，主要由优势种高山虹蚁（Iridomyrmex alpinus）驱动）、半翅目（Hemiptera）与双翅目（Diptera）在干旱及温旱复合处理组中丰度更高，但干旱处理组内幼虫个体较为稀少。综合来看，本研究表明未来地表活动型中型与大型土壤动物的丰度、群落组成乃至多样性均可能发生改变。未来需结合植被与土壤变化，聚焦群落在短、长期时间尺度上的物候转变，方能更好地理解土壤增温与干旱化所引发的潜在生态效应。