1] State Key Laboratory of Earth Surface Processes and Resource Ecology, Beijing Normal University, Beijing 100875/Zhuhai 519087, China [2] State Key Laboratory of Cryospheric Sciences, Cold and Arid Regions Environmental and Engineering Research Institute, Chinese Academy of Sciences, Lanzhou, Gansu 730000, China [3].
1] U.S. Geological Survey, Earth Resources Observation and Science Center, Sioux Falls, South Dakota 57198, USA [2].
Nat Commun. 2014 Jun 26;5:4270. doi: 10.1038/ncomms5270.
The satellite-derived normalized difference vegetation index (NDVI), which is used for estimating gross primary production (GPP), often includes contributions from both mosses and vascular plants in boreal ecosystems. For the same NDVI, moss can generate only about one-third of the GPP that vascular plants can because of its much lower photosynthetic capacity. Here, based on eddy covariance measurements, we show that the difference in photosynthetic capacity between these two plant functional types has never been explicitly included when estimating regional GPP in the boreal region, resulting in a substantial overestimation. The magnitude of this overestimation could have important implications regarding a change from a current carbon sink to a carbon source in the boreal region. Moss abundance, associated with ecosystem disturbances, needs to be mapped and incorporated into GPP estimates in order to adequately assess the role of the boreal region in the global carbon cycle.
卫星衍生的归一化差异植被指数（NDVI）常用于估算总初级生产力（GPP），但它通常包含了北方生态系统中苔藓和维管植物的共同贡献。由于苔藓的光合作用能力低得多，同样的 NDVI 下，苔藓产生的 GPP 只有维管植物的约三分之一。在这里，我们基于涡度协方差测量结果表明，在估算北方地区的区域 GPP 时，从未明确考虑这两种植物功能类型之间光合作用能力的差异，这导致了大量的高估。这种高估的幅度对于北方地区从当前的碳汇转变为碳源可能具有重要意义。与生态系统干扰相关的苔藓丰度需要进行测绘并纳入 GPP 估算中，以便充分评估北方地区在全球碳循环中的作用。
