近40年中国植被NDVI时空演变格局及主导驱动因子的差异分析

Spatial-temporal Evolution Pattern of NDVI and Its Driving Factors in China in Past 40 Years

[目的]揭示中国不同子区、不同历史时期的植被NDVI演变主导驱动因子的差异性,为不同区域植被生态系统的保护和恢复提供决策支持。[方法]基于GIMMS NDVI,MODIS NDVI及气象站点数据等,引入重心模型和地理探测器等,在地理分区视角下分析和探讨了中国植被NDVI时空演变格局及驱动机制。[结果]①1981—2019年近40 a中国植被NDVI重心向南迁移,表明南方地区的植被NDVI增量与增速要高于北方地区;②植被NDVI与气温呈正相关区域主要分布于黄土高原地区、四川盆地的中部、云贵高原以及长江中下游地区,植被NDVI与降水呈负相关区域则主要分布于云贵高原和长江中下游等地区;③1981—2019年不同分区、不同历史时期的植被NDVI演变主导驱动因子存在显著差异,随着人类活动干扰强度的增加,土地利用∩其他因子逐渐成为各子区植被生态系统演变的主导因子。[结论]近40 a中国植被状况总体上呈现改善趋势,而人类活动在植被生态系统演变过程中贡献率已高于自然因子。

[Objective]The differences in the dominant driving factors of NDVI evolution in different sub-regions and different historical periods in China were determined in order to provide important decision support for the protection and restoration of vegetation ecosystems.[Methods]Based on GIMMS NDVI,MODIS NDVI,and meteorological station data,we used a center of gravity model and geodetector to analyze and determine temporal and spatial evolution patterns and the driving mechanism of NDVI in China from the perspective of geographic division.[Results]①In the past 40 years during 1981—2019,the center of gravity of NDVI in China has shifted southward,indicating that the increment and growth rate of vegetation NDVI in Southern China were greater than in Northern China.②Regions with positive correlations between NDVI and temperature were mainly located in the Loess Plateau,the middle of the Sichuan Basin,the Yunnan-Guizhou Plateau,and the middle and lower reaches of the Yangtze River.Zones with negative correlations between NDVI and precipitation were mainly located in the middle and lower reaches of the Yangtze River and the Yunnan-Guizhou Plateau;③During 1981—2019,there were significant differences in the dominant driving factors of vegetation evolution in different regions and different historical periods.With the increasing intensity of human activities over time,land use and other factors have gradually become the dominant factors in the evolution process of vegetation ecosystems in each sub-region.[Conclusion]The vegetation condition in China has generally increased in the past 40 years,and the contribution rate attributed to human activities in the evolution of vegetation ecosystems has become greater than that of natural factors.