Vegetation plays a critical role in the water and carbon cycling and energy flow, serving as an indicator for regulating land carbon balance and reflecting climate change and human activities. We analyzed the spatiotemporal variations of normalized difference vegetation index (NDVI) during the growing season in southern Jiangxi from 2000 to 2020, using statistical methods, including the Mann-Kendall test, Theil-Sen Median analysis, Hurst index, and coefficient of variation. We employed the geodetector model to comprehensively assess the impacts of climate, topography, soil and human factors on spatial differentiation of vegetation NDVI. The results showed NDVI exhibited an upward fluctuating trend with a rate of 0.003 per year from 2000 to 2020. The proportion of high-grade and medium-high-grade NDVI areas were 55.8% and 41.9%, respectively, while the areas with low and relatively low fluctuations accounted for 92.3%. The proportions of areas showing extremely significant improvement and significant improvement were 40.4% and 19.4%, respectively. In contrast, the combined proportion of areas displaying extremely significant degradation and significant degradation was only 2.2%. The proportions of areas demonstrating continuous improvement and future improvement were 28.0% and 60.2%, respectively. Elevation, precipitation, relative humidity, temperature, landform type, land use type, population density, and nighttime light were identified as the major factors for the vairations of NDVI in the study area, followed by slope, soil type, and GDP, while slope aspect and vegetation type had indirect influence. Throughout the study period, NDVI in southern Jiangxi was overall stable, with future changes primarily indicating improvement. Notably, human factors such as land use type, population density, and nighttime light index exhibited an upward trend in their impacts on NDVI.
植被在水、碳循环和能量流动中起着重要作用,是调节陆地碳平衡和反映气候变化、人类活动的重要指标。本研究采用Mann-Kendall检验、Theil-Sen Median分析、Hurst指数和变异系数等方法分析2000—2020年赣南生长季植被归一化植被指数(NDVI)的时空变化,用地理探测器综合分析气候、地形、土壤和人为因子等对植被NDVI空间分异的影响。结果表明: 2000—2020年,植被NDVI以0.003·a-1的速率波动上升。高等级和中高等级植被NDVI面积占比分别为55.8%和41.9%,低波动变化和较低波动变化的区域面积占比为92.3%。植被NDVI极显著改善和显著改善面积占比分别为40.4%、19.4%,极显著退化和显著退化面积总占比仅为2.2%,持续改善和未来改善面积占比分别为28.0%和60.2%。高程、降水量、相对湿度、温度、地貌类型、土地利用类型、人口密度和夜间灯光指数为研究区植被NDVI的主要影响因子,其次是坡度、土壤类型和GDP,坡向和植被类型为间接影响因子。研究期间,赣南植被NDVI整体上稳定性较好,未来植被变化趋势以改善为主,人为因子中土地利用类型、人口密度和夜间灯光指数对植被NDVI的影响整体呈上升趋势。.