Novel approaches to study climate change effects on terrestrial ecosystems in the field:: Drought and passive nighttime warming
Novel approaches to study climate change effects on terrestrial ecosystems in the field:: Drought and passive nighttime warming
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DOI：
10.1007/s10021-004-0178-8
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发表时间：
2004-09-01
期刊：
影响因子：
3.7
通讯作者：
Williams, D
中科院分区：
文献类型：
--
作者：
Beier, C;Emmett, B;Williams, D
本文介绍了在野外操纵温度和水输入的新方法。夜间变暖是由红外辐射的反射造成的。自动操作的反射窗帘在夜间覆盖植被，以减少热量流失到大气中。这种方法模仿了由增加的云量和增加的温室气体排放引起的气候变化改变生态系统热平衡的方式。在2-5个月的降雨期间，通过自动用透明窗帘覆盖植被来创造干旱条件。实验方法已经在欧洲四个不同气候梯度的地点进行了评估。所有样地均以白垩科灌木为主（50%以上）。在每个站点内，建立了4米× 5米的重复地块，用于控制、增温和干旱处理，并记录对气候变量的影响。为期两年的结果表明，增温处理成功地使空气和土壤的最低温度提高了0.4-1.2℃。干旱处理导致干旱高峰期土壤水分减少33% ~ 82%。所提供的数据表明，该方法最大限度地减少了水平衡、湿度条件和光线方面的意外影响，同时导致窗帘的风速虽小但显著降低。温度测量表明，与处理相关的边缘效应很小。我们的方法为研究气候变化对偏远地区的影响提供了一个有价值的工具。
This article describes new approaches for manipulation of temperature and water input in the field. Nighttime warming was created by reflection of infrared radiation. Automatically operated reflective curtains covered the vegetation at night to reduce heat loss to the atmosphere. This approach mimicked the way climate change, caused by increased cloudiness and increased greenhouse gas emissions, alters the heat balance of ecosystems. Drought conditions were created by automatically covering the vegetation with transparent curtains during rain events over a 2-5-month period. The experimental approach has been evaluated at four European sites across a climate gradient. All sites were dominated (more than 50%) by shrubs of the ericaceous family. Within each site, replicated 4-m X 5-m plots were established for control, warming, and drought treatments and the effect on climate variables recorded. Results over a two-year period indicate that the warming treatment was successful in achieving an increase of the minimum temperatures by 0.4-1.2degreesC in the air and soil. The drought treatment resulted in a soil moisture reduction of 33%-82% at the peak of the drought. The data presented demonstrate that the approach minimizes unintended artifacts with respect to water balance, moisture conditions, and light, while causing a small but significant reduction in wind speed by the curtains. Temperature measurements demonstrated that the edge effects associated with the treatments were small. Our method provides a valuable tool for investigating the effects of climate change in remote locations with minimal artifacts.