Enhanced peak growth of global vegetation and its key mechanisms
Enhanced peak growth of global vegetation and its key mechanisms
复制标题
全球植被生长峰值增强及其关键机制。
DOI：
10.1038/s41559-018-0714-0
复制
发表时间：
2018-12-01
影响因子：
16.8
通讯作者：
Luo, Yiqi
中科院分区：
文献类型：
--
作者：
Huang, Kun;Xia, Jianyang;Luo, Yiqi
植被的年峰值生长对于表征陆地生态系统生产力的能力和塑造大气二氧化碳浓度的季节性至关重要。最近全球土地的绿化表明了陆地植被增长的趋势，但是否在全球范围内提高了增长的峰值仍不清楚。在这里，我们使用两个全球总初级生产力(GPP)数据集和卫星获取的归一化差异植被指数(NDVI)来描述年植被生长峰值(即GPPmax和NDVImax)的最近变化。我们证明，在过去的三十年里，全球植被生长的峰值一直在线性增加。约65%的NDVImax变化是由耕地扩大(21%)、二氧化碳增加(22%)和氮沉降加剧(22%)平均解释的。从涡流塔、太阳诱导的叶绿素荧光和全球植物特征数据库的测量证实了扩大农田对峰值生长趋势的贡献，所有这些都表明农田具有比其他植被类型更高的光合作用能力。二氧化碳的巨大贡献也得到了对466个操纵实验和15个陆地生物圈模型的荟萃分析的支持。此外，我们还发现，在热带地区，GPPmax对年GPP变化的贡献小于其他地区。这些多方面的证据表明，全球植被生长的峰值有增加的趋势。研究结果强调了农业集约化和大气变化在重塑全球植被生长季节性方面的重要作用。
The annual peak growth of vegetation is critical in characterizing the capacity of terrestrial ecosystem productivity and shaping the seasonality of atmospheric CO2concentrations. The recent greening of global lands suggests an increasing trend of terrestrial vegetation growth, but whether or not the peak growth has been globally enhanced still remains unclear. Here, we use two global datasets of gross primary productivity (GPP) and a satellite-derived Normalized Difference Vegetation Index (NDVI) to characterize recent changes in annual peak vegetation growth (that is, GPPmaxand NDVImax). We demonstrate that the peak in the growth of global vegetation has been linearly increasing during the past three decades. About 65% of the NDVImaxvariation is evenly explained by expanding croplands (21%), rising CO2(22%) and intensifying nitrogen deposition (22%). The contribution of expanding croplands to the peak growth trend is substantiated by measurements from eddy-flux towers, sun-induced chlorophyll fluorescence and a global database of plant traits, all of which demonstrate that croplands have a higher photosynthetic capacity than other vegetation types. The large contribution of CO2is also supported by a meta-analysis of 466 manipulative experiments and 15 terrestrial biosphere models. Furthermore, we show that the contribution of GPPmaxto the change in annual GPP is less in the tropics than in other regions. These multiple lines of evidence reveal an increasing trend in the peak growth of global vegetation. The findings highlight the important roles of agricultural intensification and atmospheric changes in reshaping the seasonality of global vegetation growth.