植被冠层对温带和亚热带成熟林生态系统碳交换的调控作用研究

As the important interaction interface between ecosystem and atmosphere, canopy plays the key role in the regulation on the exchanges of trace gases and energy, which has been paid more and more attention recently. However, the comprehensive understanding on such role is still very lack. In this study, two mature forests, a temperate mix forest and a subtropical evergreen mixed forest are selected. Firstly, seasonal and interanual variability of ecosystem carbon flux and its relatively contribution from climate abnormal and biological function change will be evaluated base on 15 years flux measurement with eddy covariance technique. Secondly, the controlling of ecosystem primary production on different components of ecosystem respiration will be illuminated with the manipulative experiment on the different sources of soil respiration, and the allocation of ecosystem primary production can be also be clarified within the two mature forest ecosystems. Thirdly, the influences of the variations from plant phenology, photosynthetic characteristics will be studied with the dynamic measurement of leaf photosynthesis and the reversion of canopy photosynthetic capacity using flux data. Fourthly, the correlation between the stoichiometric ratios within C, N, P of canopy and ecosystem carbon flux will be evaluated. With the consideration on the interactions among different canopy attributes, the regulation and the underling mechanisms will be revealed and compared between the two mature forest with different nutrient condition from different climatic zones.

植被冠层作为生态系统-大气相互作用的重要界面，在调控生态系统物质和能量交换过程中的重要作用日益受到重视，但对其作用机制尚缺乏系统的认识。拟以我国温带针阔混交林和南亚热带季风常绿混交林两个成熟林为研究对象，基于涡度相关技术获取生态系统碳通量15年连续观测数据，揭示生态系统碳交换季节变化和年际变异及其气候变异和生物功能变化的相对贡献；开展土壤呼吸不同组分的动态观测，阐明生态系统光合对呼吸组分的控制作用，揭示光合碳吸收在不同成熟林生态系统中的分配模式及其动态变化；基于通量观测和植被指数测定，并结合叶片光合参数的动态观测和冠层光合参数反演，揭示物候和光合属性变化对生态系统碳交换的影响；开展植物和土壤C、N、P等生源要素的动态测定，探讨生态化学计量关系和生态系统碳交换的相互联系。在考虑不同属性相互作用的基础上，综合评价不同气候区、不同养分条件成熟林的植被冠层对生态系统碳交换的调控作用。

植被冠层作为生态系统-大气相互作用的重要界面，在调控生态系统物质和能量交换过程中的重要作用日益受到重视，但对其作用机制尚缺乏系统的认识。以我国温带针阔混交林和南亚热带季风常绿混交林两个成熟林为研究对象，通过系统收集生态系统碳交换观测数据、群落清查数据、土壤温室气体通量监测数据和遥感指数数据，构建了两个生态系统碳交换及其生物与环境响应研究综合数据集。基于涡度相关技术获取生态系统碳通量多年连续观测数据，揭示了生态系统碳交换季节变化和年际变异及其气候变异和生物功能变化的相对贡献；开展了土壤呼吸不同组分的动态观测，阐明了生态系统光合对呼吸组分的控制作用，揭示了光合碳吸收在不同成熟林生态系统中的分配模式及其动态变化；揭示了物候和光合属性变化对生态系统碳交换的影响。研究结果对于认识和理解植被冠层在两个老龄林生态系统碳交换中的作用，以及揭示生态系统碳收支及其组分的动态变化与生物和非生物因子控制作用方面具有重要意义。