藏北两个临近不同高寒草地碳通量对气候条件的响应  

Climate responses of carbon fluxes in two adjacent alpine grasslands in northern Tibet

作　　者：徐玲玲[1] 牛犇[2] 张宪洲[2,3] 何永涛 石培礼[2,3] 宗宁 武建双[4] 王向涛 XU Ling-ing;NIU Ben;ZHANG Xian-zhou;HE Yong-tao;SHI Pei-li;ZONG Ning;WU Jian-shuang;WANG Xiang-tao(National Meteorological Center of China Meteorological Administration,Beijing 100081,China;Lhasa National Ecological Research Station,Key Laboratory of Ecosystem Network Observation and Modelling,Institute of Geographic Sciences and Natural Resources Research,Chinese Academy of Sciences,Beijing 100101,China;College of Resources and Environment,University of Chinese Academy of Sciences,Beijing 100049,China;Institute of Environment and Sustainable Development in Agriculture,Chinese Academy of Agricultural Sciences,Beijing 100081,China;Department of Animal Sciences,Xizang Agriculture and Animal Husbandry College,Linzhi 860000,China)

机构地区：[1]中国气象局国家气象中心,北京100081 [2]中国科学院地理科学与资源研究所,生态系统网络观测与模拟重点实验室,拉萨高原生态试验站,北京100101 [3]中国科学院大学资源与环境学院,北京100049 [4]中国农业科学院农业环境与可持续发展研究所,北京100081 [5]西藏农牧学院动物科学学院,西藏林芝860000

出　　处：《草业学报》2024年第6期1-16,共16页Acta Prataculturae Sinica

基　　金：西藏自治区重点研发计划项目(XZ202201ZY0016G);西藏自治区重大科技专项(XZ202101ZD0007G);国家自然科学基金项目(41807331,31700421)资助。

摘　　要：生态系统碳循环应对气候变化的敏感性研究是“碳中和”背景下的重要议题。青藏高原高寒草地面积广阔,碳储量丰富,脆弱性高,近年来随着观测技术尤其是涡度相关技术和模拟技术的发展,已有不少研究致力于揭示青藏高原高寒草地生态系统碳水通量对气候变化的响应过程。但是,相同气候背景下不同高寒草地类型对环境变化的响应规律及敏感性尚不清楚。本研究基于藏北高原两个临近的高寒草地生态系统,高寒草甸和高寒湿地涡度相关观测的碳水通量数据,对比分析了不同水分条件下藏北高寒草甸和高寒湿地碳循环的气候敏感性。结果表明,高寒草甸的碳交换量要显著小于高寒湿地,高寒草甸是碳中性的,年净CO_(2)交换量为(18.09±40.66) g C·m^(-2) ,而高寒湿地是稳定的碳汇,年净CO_(2)固定量为(155.09±32.85)g C·m^(-2) 。水分条件对高寒草甸和高寒湿地植被光响应曲线最大的光合速率(α)的影响较弱,与饱和光强下的总初级生产力(Amax)呈显著正相关关系。水分对生态系统呼吸与温度的指数响应关系的调节作用主要体现在基础呼吸值(a)上,高寒湿地a的均值是高寒草甸的3.76倍,而对两个高寒草地生态系统呼吸敏感性(Q10)的调节均不显著。高寒草甸和高寒湿地Q10的均值(1.84)以及随温度升高而减小的趋势基本一致。藏北高寒草地生态系统的碳源汇特征对环境因子的响应取决于多因素共同限制,因此,基于区域性的联网协同观测有助于更加清晰地理解高寒生态系统碳交换响应气候变化的机理。The sensitivity of ecosystem carbon cycle to climate change is an important issue in the context of carbon neutrality across the globe.Because of the vast area,rich carbon storage,and vulnerability of the alpine grassland on the Qinghai-Tibetan Plateau,many site-specific studies have focused on the responses of carbon and water fluxes of alpine grassland to climate change in recent years.In such studies,various observation and simulation techniques,especially eddy correlation(EC)techniques,have been used.However,the sensitivity of different alpine grassland types to changes in climatic factors under the same climatic background remains unclear.Based on the estimates of carbon and water fluxes made using EC techniques from 2009 to 2011 under different water conditions,this study analyzed and compared the climate sensitivity of the carbon cycle between two adjacent(<5 km)alpine grassland ecosystems,alpine meadow and alpine wetland,in northern Tibet.The results showed that the carbon exchange capacity of alpine meadow was significantly lower than that of alpine wetland.The alpine meadow was carbon neutral with an annual net CO_(2) exchange(NEE)of 18.09±40.66 g C·m^(-2) ,while the alpine wetland was a stable carbon sink with an annual NEE of 155.09±32.85 g C·m^(-2) .The moisture conditions weakly affected the maximum photosynthetic rate of the light response curves in both alpine meadow and alpine wetland,but was significantly positively correlated with gross primary productivity under saturated light intensity.The effect of moisture conditions to regulate the exponential response relationship between ecosystem respiration(Re)and temperature was mainly reflected by the basic respiration value(a).The mean a value of alpine wetland was 3.76-times larger than that of alpine meadow,but the effect of moisture conditions to regulate the temperature sensitivity of Re(Q10)in the two alpine grasslands was not significant.The mean value of annual Q10(1.84)and the trend of Q10 to decrease with temperature were basically the

关 键 词：碳循环 高寒草地 气候 敏感性 藏北高原 

分 类 号：S812[农业科学—草业科学]