Varghese S, Aguirre B A, Isbell F, Wright A J
Department of Biological Sciences California State University Los Angeles Los Angeles California USA.
Department of Ecology, Evolution and Behavior University of Minnesota Minneapolis Minnesota USA.
Ecol Evol. 2024 Aug 21;14(8):e70139. doi: 10.1002/ece3.70139. eCollection 2024 Aug.
As global temperatures rise, droughts are becoming more frequent and severe. To predict how drought might affect plant communities, ecologists have traditionally designed drought experiments with controlled watering regimes and rainout shelters. Both treatments have proven effective for simulating soil drought. However, neither are designed to directly modify atmospheric drought. Here, we detail the efficacy of a silica gel atmospheric drought treatment in outdoor mesocosms with and without a co-occurring soil drought treatment. At California State University, Los Angeles, we monitored relative humidity, temperature, and vapor pressure deficit every 10 min for 5 months in bare-ground, open-top mesocosms treated with soil drought (reduced watering) and/or atmospheric drought (silica dehumidification packets suspended 12 cm above soil). We found that silica packets dehumidified these mesocosm microclimates most effectively (-5% RH) when combined with reduced soil water, regardless of the ambient humidity levels of the surrounding air. Further, packets increased microclimate vapor pressure deficit most effectively (+0.4 kPa) when combined with reduced soil water and ambient air temperatures above 20°C. Finally, packets simulated atmospheric drought most consistently when replaced within 3 days of deployment. Our results demonstrate the use of silica packets as effective dehumidification agents in outdoor drought experiments. We emphasize that incorporating atmospheric drought in existing soil drought experiments can improve our understandings of the ecological impacts of drought.
随着全球气温上升，干旱正变得愈发频繁和严重。为了预测干旱可能如何影响植物群落，生态学家传统上通过控制浇水制度和遮雨棚来设计干旱实验。这两种处理方法都已证明对模拟土壤干旱有效。然而，它们都不是为直接改变大气干旱而设计的。在此，我们详细阐述了硅胶大气干旱处理在有或没有同时进行土壤干旱处理的室外中型生态系统中的效果。在加州州立大学洛杉矶分校，我们在经过土壤干旱（减少浇水）和/或大气干旱（在土壤上方12厘米处悬挂硅胶除湿包）处理的裸地、开放式顶部中型生态系统中，每10分钟监测一次相对湿度、温度和水汽压亏缺，持续5个月。我们发现，硅胶包与减少土壤水分相结合时，无论周围空气环境湿度如何，都能最有效地使这些中型生态系统微气候除湿（相对湿度降低5%）。此外，当与减少土壤水分以及高于20°C的环境空气温度相结合时，硅胶包能最有效地增加微气候水汽压亏缺（增加0.4千帕）。最后，硅胶包在部署后3天内更换时能最持续地模拟大气干旱状态。我们的结果证明了硅胶包在室外干旱实验中作为有效除湿剂的用途。我们强调，在现有的土壤干旱实验中纳入大气干旱因素能够增进我们对干旱生态影响的理解。
