干旱半干旱地区草地碳循环关键过程对降雨变化的响应

Responses of Carbon Cycling Key Processes to Precipitation Changes in Arid and Semiarid Grassland Ecosystems: A review

未来全球气候变化背景下,全球或局部地区的降雨量及降雨时间分布将发生一定的变化。草地生态系统在全球碳收支中作用显著,对气候变化的反馈起着重要的作用。但由于草地多处于干旱半干旱地区,受到水分条件的限制,对降雨变化响应敏感,其碳源汇功能表现出很大的不确定性。为了更好地预测未来全球气候变化背景下草地的碳源汇功能及其对气候变化的进一步反馈,有必要深入研究决定草地碳源汇功能的两大碳循环关键过程——净初级生产力和土壤呼吸对降雨变化的响应特征及机制。本文对国内外有关草地生产力和土壤呼吸如何对降雨量、降雨强度、降雨频率和间隔时间进行响应的相关研究成果进行了综述,在此基础上指出了目前研究存在的不足,并对未来相关的重点研究方向进行了探讨和展望。

Climate models predict that the amounts and the timing of precipitation will change in the future,both globally and regionally.Given the sensitivity of grassland to water availability in arid and semiarid areas,the variability of precipitation will undoubtedly influence the net primary production（NPP） and soil respiration（Rs）,the two most key processes of carbon cycles in these ecosystems.And then,it can change the carbon budget of grassland.Thus,in order to better predict the function of carbon budget of grassland in future precipitation scenario,it is crucial to investigate the responses of the two key processes（NPP and Rs） to precipitation changes in arid and semiarid grassland ecosystems.This paper reviews research progress at home and abroad on how NPP and Rs respond to precipitation changes,points out the areas for improvement and discusses about the topics where more focus is needed in the future：（1） Study of the effects of precipitations intensity,frequency and interval on the responses of NPP,especially below ground NPP;（2） By better categorizing the components of soil respiration and studying the temporal and spatial variability of NPP and Rs,further explore the mechanism of their responses to the changing precipitation regimes;（3） Long term in-situ field research on th＂e lagged effects＂ of the responses of NPP and Rs to climate change.