Response of grassland ecosystems to the global climate change

草原生态系统对全球气候变化的响应

基本信息

批准号：
18510013
负责人：
NAKANO Tomoko
金额：
$ 2.18万
依托单位：
Tokyo Metropolitan University
依托单位国家：
日本
项目类别：
Grant-in-Aid for Scientific Research (C)
财政年份：
2006
资助国家：
日本
起止时间：
2006 至 2007
项目状态：
已结题

项目摘要

In Mongolia,grassland covers approximately 80% of the country and comprises a major part of East Asian grasslands. The plants live in a semi-arid climate,and have often suffered from droughts.Global climate models predict that future increases in atmospheric carbon dioxide (CO2) will cause significant drying in this region during summer,caused by increased temperature and potential evaporation. Studies have indicated that the grasslands respond sensitively to changes in climate,particularly to changes in precipitation. The objective of this study was to evaluate the quantitative dependence of photosynthetic production and ecosystem respiration on temperature,moisture,radiation,and plant biomass in a semi-arid grassland. Toward this aim,we measured CO2 fluxes using a dosed-chamber technique in a grassland in Mongolia and in an environmental control equipment in Tottori University. As a result,we found that (1) values of gross primary production (GPP) were linearly related to live aboveground biomass (AGB) enclosed by the chamber, (2) GPP/AGB fit well a rectangular hyperbolic light-response curve for all the study periods,but when the air and soil were dry,considerable reduction in GPP was observed, (3) the GPP/AGB ratio was also expressed as individual functions of air temperature,vapor pressure deficit,and volumetric soil water content,and (4) values of Reco were expressed well as a bivariate function of soil temperature and soil moisture near the soil surface.

在蒙古，草原占地约80％，包括东亚草原的主要部分。这些植物生活在半干旱的气候中，经常遭受干旱。Global气候模型预测，未来大气二氧化碳（CO2）的未来增加将在夏季由于温度升高和潜在蒸发而导致该地区的显着干燥。研究表明，草原对气候变化的反应敏感，特别是对降水的变化。这项研究的目的是评估半干旱草原中光合产生和生态系统呼吸对温度，水分，辐射和植物生物量的定量依赖性。为了实现这一目标，我们在蒙古的草原和托托里大学的环境控制设备中使用剂量腔室技术测量了二氧化碳通量。结果，我们发现（1）（1）（1）与室封闭的地面生物量（AGB）的（GPP）的值是线性相关的，（2）GPP/AGB非常适合所有研究期间的矩形双质量响应曲线，在所有研究期间，当空气和土壤中的大量降低时，GPP的功能是（3），GPP的功能是（3）GPP（3）（3）（3）（3）（3）（3）（3）（3）（3）ravio carviore（3）（3）（3）（3）均值（3）racb capaire（3）rat caviio car cavio carevect/agb ab。温度，蒸气压力不足和体积土壤水含量以及（4）RECO值表达为土壤温度和土壤表面附近土壤水分的双变量功能。