北京松山天然落叶阔叶林生态系统净碳交换特征及其影响因子  

Net ecosystem carbon exchange and its affecting factors in a deciduous broad-leaved forest in Songshan, Beijing, China

作　　者：李润东 范雅倩 冯沛 宋泽 李鑫豪 闫惠娟 马莉 查天山[1,2] LI Run-dong;FAN Ya-qian;FENG Pei;SONG Ze;LI Xin-hao;YAN Hui-juan;Ma Li;ZHA Tian-shan(School of Soil and Water Conservation,Beijing Forestry University,Beijing 100083,China;Key Laboratory of State Forestry Administration on Soil and Water Conservation,Beijing Forestry University,Beijing 100083,China;Beijing Song-shan National Nature Reserve Administration,Beijing 102100,China;Beijing Landscape Design Engineering Co.Ltd.,Beijing 100029,China)

机构地区：[1]北京林业大学水土保持学院,北京100083 [2]北京林业大学水土保持国家林业局重点实验室,北京100083 [3]北京松山国家级自然保护区管理处,北京102100 [4]北京市园林设计工程有限公司,北京100029

出　　处：《应用生态学报》2020年第11期3621-3630,共10页Chinese Journal of Applied Ecology

基　　金：国家自然科学基金项目(31361130340)资助。

摘　　要：森林生态系统在陆地碳循环过程中发挥着重要作用,关于温带落叶阔叶林生态系统碳平衡过程影响机制的讨论尚未统一。本研究于2019年对北京松山典型落叶阔叶林生态系统的净碳交换量(NEE)及空气温度(Ta)、土壤温度(Ts)、光合有效辐射(PAR)、饱和水气压差(VPD)、土壤含水量(SWC)、降雨量(P)等环境因子进行原位连续监测,分析松山落叶阔叶林生态系统净碳交换特征及其对环境因子的响应。结果表明:在日尺度上,NEE生长季(5—10月)各月平均日变化均呈"U"字形变化,日间为碳汇,夜间为碳源。其他月份NEE均为正值,变化平缓,表现为碳源。在季节尺度上,NEE呈单峰曲线变化规律,全年NEE为-111 g C·m-2·a-1,生态系统呼吸总量(Re)为555 g C·m-2·a-1,总生态系统生产力(GEP)为666 g C·m-2·a-1。碳吸收与释放量分别在6月与11月达到最大值。PAR是影响日间净碳交换量(NEEd)的主导因子,二者关系符合Michaelis-Menten模型,VPD是间接影响NEEd的主导因子,最适宜日间净碳交换的VPD范围为1~1.5 kPa。土壤温度是影响夜间净碳交换量(NEEn)的主导因子,SWC是NEEn的限制因子,SWC过高或过低均会对NEEn产生抑制,最适值为0.28 m3·m-3。Forests play an important role in terrestrial carbon cycles. The mechanism underlying carbon balance in temperate deciduous broad-leaved forests is not clear. In this study, net ecosystem exchange(NEE) and environmental factors, including air temperature(Ta), soil temperature(Ts), photosynthetically active radiation(PAR), vapor pressure deficit(VPD), soil water content(SWC) and precipitation(P) were continually measured using eddy covariance techniques in 2019 in a deciduous broad-leaved forest in Songshan, Beijing. We analyzed the characteristics of NEE and its response to environmental factors. The results showed that, at diurnal scale, the monthly averaged NEE exhibited a "U" shape curve(i.e., being a carbon sink over daytime while being a carbon source during nighttime) over the growing season. During the non-growing season, NEE was positive(i.e., carbon source) at diurnal scale. At the seasonal scale, NEE exhibited a unimodal curve. The annual cumulative NEE was-111 g C·m-2·a-1. Annual ecosystem respiration was 555 g C·m-2·a-1, while gross ecosystem productivity was 666 g C·m-2·a-1. Carbon sequestration peaked in June, while emission peaked in November. PAR was the dominant factor affecting daytime NEE(NEEd). VPD was the main factor that indirectly affected daytime NEEd, with an optimal VPD value that maximizes daytime NEE around 1-1.5 kPa. Soil temperature was the main factor affecting nighttime NEE(NEEn). SWC was a limiting factor for NEEn. Too high or too low SWC would inhibit NEEn, with an optimal SWC value of 0.28 m3·m-3.

关 键 词：净生态系统交换 涡度相关法 环境因子 通径分析 

分 类 号：S718.55[农业科学—林学]