中国陆地生态系统净初级生产力时空变化特征及影响因素

为揭示气候变化背景下我国各陆地生态系统净初级生产力(NPP)的时空分布特征与驱动机制，引入重心模型分析2000—2017年我国NPP的空间分布格局变化，并利用相关分析方法结合Thornthwaite Memorial模型定量区分气候变化与人类活动影响NPP的相对作用。结果表明：(1)2000—2017年全国NPP均值为325.86 g C/m²,整体呈现出南方高北方低，东南向西北逐渐递减的特点。(2)近18年全国与各陆地生态系统NPP均呈现增长趋势，全国NPP增长速率为4.4597 g C m^-2 a^-1,总净增加约0.391 Pg C。空间上全国与森林、草地、荒漠生态系统的NPP重心向东北方向移动，农田与城市生态系统的NPP重心向西北方向移动，表明NPP在该方向上的增速和增量最大。(3)全国NPP在华北、西北地区与四川盆地主要受降水的影响，在青藏高原与云贵高原的东部主要受气温的影响，各陆地生态系统之间城市生态系统NPP对降水响应的敏感度相对最高，荒漠生态系统NPP对温度响应的敏感度相对最高。(4)气候变化和人类活动对全...

Analysis of spatio-temporal variation characteristics and influencing factors of net primary productivity in terrestrial ecosystems of China

In order to reveal the spatio-temporal distribution characteristics and driving mechanism of net primary productivity (NPP) in each terrestrial ecosystem of China under climate change, this study introduces the barycenter model to analyze the spatial distribution pattern changes of NPP in China from 2000 to 2017 and investigates the spatial distribution of the influence of precipitation and temperature, which are two key climate factors on the NPP, by correlation analysis. Furthermore, the Thornthwaite Memorial model is used to quantitatively distinguish the relative effects of climate change and human activities on NPP subsequently. The results show that:(1) from 2000 to 2017, the mean value of NPP in China was 325.86 g C/m², with higher values in the south and lower values in the north, and gradually decreasing from southeast to northwest. (2) In the past 18 years, the NPP in China and all terrestrial ecosystems showed a growing trend, with the increase rate of 4.4597 g C m^-2 a^-1, and a total net increase of 0.391 Pg C. The NPP barycenter of national and forest, grassland and desert ecosystems moved to the northeast, while that of farmland and urban ecosystems moved to the northwest, indicating that the growth and increment of NPP have been the greatest in this direction. (3) The NPP was mainly affected by precipitation in north and northwest China and Sichuan Basin, while the NPP in the Qinghai-Tibet Plateau and eastern Yunnan-Guizhou Plateau was mainly affected by temperature. Meanwhile, among the terrestrial ecosystems, NPP of the urban ecosystem was the most sensitive to precipitation response, while that of the desert ecosystem was the most sensitive to temperature response. (4) The contribution of climate change and human activities to national NPP change accounts for about 56% and 44% respectively, and the NPP of each terrestrial ecosystem was also affected by climate change more than by human activities. At the same time, both climate change and human activities led to the net increase of NPP. In addition, climate change had the greatest impact on the NPP of desert ecosystem, and the least impact on the NPP of forest ecosystem, while human activities had the opposite impact on the NPP of each terrestrial ecosystem. Research shows that although each terrestrial ecosystem has been characterized by a favorable increase of NPP under the impacts of climate change and human activities, there are still some areas that are negatively affected by human activities, such as the southeast of Qinghai-Tibet Plateau and the provinces along the southeast coast of China. Therefore, these regions must fully consider the effects of harmful human behaviors such as overgrazing and urban sprawl in future environmental protection planning, and formulate relevant policy guidance to encourage the improvement of regional environmental conditions. The results can provide a scientific basis for the Chinese ecological environment protection, rational allocation of resources and strategic decision-making of environment, social and economic development.