Response of plant biomass and soil respiration to experimental warming and precipitation manipulation in a Northern Great Plains grassland
Response of plant biomass and soil respiration to experimental warming and precipitation manipulation in a Northern Great Plains grassland
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DOI：
10.1016/j.agrformet.2013.01.002
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发表时间：
2013-05-15
影响因子：
6.2
通讯作者：
Letts, Matthew G.
中科院分区：
文献类型：
--
作者：
Flanagan, Lawrence B.;Sharp, Eric J.;Letts, Matthew G.
温度变化和降水的相互作用效应预计将对生态系统净碳储量产生重大影响。在这里，我们报告的实验结果，评估温度升高，改变降水，单独和组合，在北方大平原草原，莱斯布里奇附近，加拿大阿尔伯塔省阿尔伯塔植物生物量生产和土壤呼吸速率的影响。在2011年，使用开顶室和避雨棚建立了一个实验，其中有两个温度处理（加热和控制），每个温度处理与三个降水处理（负50%，环境（无操作）和正50%）相结合。在2012年进行了一个只有两种温度处理的小型实验，这一年的降雨量比2011年少。我们的目标是确定植物生物量生产和土壤呼吸的温度和湿度的操作的敏感性，并测试土壤呼吸速率的环境变化的直接和间接影响。实验操作主要导致加热处理中空气温度的显著增加。温度或降水处理对土壤含水量没有显著影响。地面生物量没有显着影响的实验操作，但温暖的地块的环境降水处理显示，在2011年的根生物量相对于对照地块增加。与对照相比，2011年温暖处理增加了土壤呼吸（7 - 9月）中碳的累积损失497 g C m（-2），2012年增加了185 g C m（-2）。这两年较高的土壤呼吸速率不是直接引起的显着差异，在土壤温度或土壤水分的治疗，但可能是一个间接的结果，增加碳基质的可用性在温暖的相对于控制治疗。(C)2013爱思唯尔有限公司版权所有。
The interacting effects of altered temperature and precipitation are expected to have significant consequences for ecosystem net carbon storage. Here we report the results of an experiment that evaluated the effects of elevated temperature and altered precipitation, alone and in combination, on plant biomass production and soil respiration rates in a northern Great Plains grassland, near Lethbridge, Alberta Canada. Open-top chambers and rain shelters were used to establish an experiment in 2011 with two temperature treatments (warmed and control), each combined with three precipitation treatments (minus 50%, ambient (no manipulation), and plus 50%). A smaller experiment with only the two temperature treatments was conducted in 2012, a year with less rain than 2011. Our objectives were to determine the sensitivity of plant biomass production and soil respiration to temperature and moisture manipulations, and to test for direct and indirect effects of the environmental changes on soil respiration rates. The experimental manipulations resulted primarily in a significant increase in air temperature in the warmed treatment. There were no significant temperature or precipitation treatment effects on soil moisture content. Above-ground biomass was not significantly affected by the experimental manipulations, but the warmed plots of the ambient precipitation treatment showed an increase in root biomass relative to the control plots in 2011. The warmed treatment increased the cumulative loss of carbon in soil respiration (July-September) compared to the control by 497 g C m(-2) during 2011, and by 185 g C m(-2) during 2012. This higher soil respiration rate in both years was not directly caused by significant differences among treatments in soil temperature or soil moisture, but was likely an indirect result of increased carbon substrate availability in the warmed relative to the control treatment. (C) 2013 Elsevier B.V. All rights reserved.