草原生态系统碳循环对降雨的响应阈值及机理研究

项目名称： 草原生态系统碳循环对降雨的响应阈值及机理研究

项目编号： No.31470528

项目类型： 面上项目

立项/批准年度： 2015

项目学科： 生物科学

项目作者： 牛书丽

作者单位： 中国科学院地理科学与资源研究所

项目金额： 86万元

中文摘要： 全球气候变化对陆地生态系统的结构和功能已经产生急剧影响，当影响超过生态系统阈值时，生态系统服务功能将发生崩溃。然而，我们对生态系统阈值的理解还知之甚少，尤其是缺乏对其形成机制和诱发系统阈值改变的因子的了解。本研究以脆弱生态系统川西北高寒草甸为研究对象，用生态系统水平上降雨控制实验，研究高寒草甸生态系统碳循环关键过程尤其是地下碳循环过程对降雨梯度的响应，揭示并量化高寒草甸碳循环对降雨梯度的响应阈值，探讨地上和地下碳循环过程对降雨梯度响应异同的生态学机制。该研究有助于揭示生态系统对全球变化的响应阈值及机理，并为高寒草原生态系统初级生产力和碳储量的模型预测提供参数检验和模型验证。

中文关键词： 气候变化；碳循环；阈值；高寒草甸；草原生态系统

英文摘要： Global climatic change has profoundly impacted the structure and function of terrestrial ecosystem. The function of ecosystem services would lose when the impacts of climatic change on ecosystem exceed its threshold. So far, we have limited understanding of ecosystem's threshold responses, and especially have little understanding of the factors and mechanisms that cause the threshold responses. This study will be conducted in an alpine meadow in Sichuan, China. We will use manipulative experiments combined with pot experiments to investigate the responses of ecosystem carbon cycle (especially the processes of belowground carbon cycle) to changes in precipitation. We aim to find the tipping point of carbon cycle in response to the precipitation gradient, and reveal the mechanisms of different performances between aboveground and belowground carbon cycle processes. Furthermore, we will study the divergent threshold responses of grassland ecosystem in the fenced and unfenced plots, in order to reveal how human activities influence the threshold responses of grassland ecosystem to climatic change. This study will be helpful to understand ecosystem's responses to climatic change, and will provide parameters for models that used for predicting ecosystem primary productivity and carbon stocks in this alpine meadow.

英文关键词： climate change;carbon cycle;threshold;alpine meadow;grassland ecosystem