链接植物功能性状与中亚热带人工林生态系统碳通量观测研究

植物功能性状与植物光合和呼吸速率密切相关，显著影响净生态系统生产力(NEP)及其组分。将植物个体性状拓展为生态系统性状是解析NEP生物学机制的核心挑战。以往研究通常基于单次采样并忽略物候动态，关注物种和群落性状研究。拟以ChinaFLUX江西千烟洲中亚热带人工林为研究对象，基于涡度协方差技术量化NEP，并拆分为光合和呼吸的差值、表达为碳吸收(释放)强度和持续时间的积分或相对不易变参数及相应变量的函数等。在通量气候贡献区设置样地并调查，根据物候动态定期采集并分析乔-灌-草的叶-茎-根相对稳定的形态、化学、物候性状以及土壤属性，用δ13C和δ18O指示相对易变的生理性状。结合生物量和比叶面积将物种性状拓展至生态系统性状，评价并揭示物种、群落和生态系统叶-茎-根多功能性状组合的季节变异及其权衡关系的异同；链接生态系统功能性状与NEP及其组分，综合揭示NEP及其组分季节变异的生物和环境控制机制。

Plant functional traits are closely related to the plant photosynthetic and respiration rates, and significantly affect the variations of net ecosystem productivity (NEP) and its components. Scaling the functional traits measured at the individual level of species up to ecosystem functional trait is the key challenge for elucidating the biological control mechanisms of the NEP. Previous studies usually focused on the species and community functional traits. These studies usually only collected samples once a year during the growing season, ignoring the functional trait variations caused by phenological dynamics. In this research, in-suit observation and field experiments will be conducted in a subtropical plantation ecosystem of Qianyanzhou station in ChinaFLUX. Based on the eddy covariance technique, the NEP will be directly measured, and partitioned into the difference of gross ecosystem primary productivity (GPP) and ecosystem respiration (RE), or expressed as the integration of carbon uptake or release peak and corresponding duration, or expressed as relatively stable parameters and the corresponding functions. We will set up plots in the flux footprint climatology, collect and analyze the relatively stable morphological, chemical, phenological traits of leaf-stem-root of different life form species (trees, shrubs and herbs) according to the phenological phase. The δ13C and δ18O will be used as the proxies of the relatively variable physiological traits. In combination with the biomass and specific leaf area data, we try to scale the species functional traits up to ecosystem functional traits, to evaluate and reveal the seasonal variations and the trade-off relationships of species, community, and ecosystem multi-functional traits combinations of root-stem-leaf and the similarities and differences, to link the ecosystem functional traits and the NEP and its components, to comprehensively reveal the biological and environmental mechanisms of the seasonal variation of NEP and its components.