我国北方山地灌丛土壤呼吸对降水量增减变化的响应及其机制

项目名称： 我国北方山地灌丛土壤呼吸对降水量增减变化的响应及其机制

项目编号： No.31500448

项目类型： 青年科学基金项目

立项/批准年度： 2016

项目学科： 生态学

项目作者： 沈会涛

作者单位： 河北省科学院地理科学研究所

项目金额： 20万元

中文摘要： 土壤呼吸作为陆地生态系统碳循环的重要环节，对调控全球气候变化发挥着重要作用。土壤呼吸对降水量变化响应的不确定性，影响着气候变化条件下碳平衡的准确评估。灌丛是未来固碳增汇的潜力区，但全球气候变化情景下的碳循环研究却较薄弱。本研究将围绕降水量增减变化与土壤呼吸的关系这一问题，选择我国北方山地荆条灌丛作为研究对象，采用野外控制降水试验（自然状态、自然状态增加30 %和自然状态减少30 %），研究降水量增减变化条件下土壤呼吸及其组分以及相关环境因子的动态规律，确定自养呼吸和异养呼吸对土壤呼吸的相对贡献率，并通过建立土壤呼吸的结构方程模型来探讨影响土壤呼吸的各环境因子之间的相互作用关系，旨在阐明降水量增减变化对灌丛土壤呼吸的影响机制，以期为全球气候变化背景下灌丛土壤CO2排放响应研究提供基础数据。

中文关键词： 碳循环；降水量变化；灌丛；环境因子；结构方程模型

英文摘要： Soil respiration is the second largest carbon flux in terrestrial ecosystems, and plays a critical role in global carbon cycling. Precipitation, which acts as an important disturbance to soil respiration, leads to large uncertainties in estimating carbon exchange between the soil and the atmosphere. Shrublands are a widespread vegetation type that often have high carbon sequestration potential value. However, only a few of researches have studied the carbon flux of shrublands in the scenario of global climate change. To indentify the effect of changing precipitation on soil respiration in montane shrubland, three precipitation-manipulation treatments were designed to reflect potential changes in precipitation regimens: +30% precipitation water supplementation; -30% precipitation water droughting; and current conditions (no manipulation of water availability). The objective of the present research is to quantify the impact of precipitation changes on soil respiration and its components. Furthermore, response of soil respiration and its components to abiotic and biotic drivers are assessed. At last, the combined effects of environmental variables on soil respiration are analyzed by the use of Structural Equation Modeling (SEM). The present study considering precipitation changes are needed to properly assess future trends in soil CO2 fluxes under scenarios of global climate change.

英文关键词： carbon cycling;precipitation changes;shrubland;environmental variables;Structural Equation Modeling