基于地理探测器的河南省植被NDVI时空变化及驱动力分析

Temporal and spatial variations and driving force analysis of NDVI in Henan Province based on Geodetector

植被作为陆地生态系统的主体,能够有效反映全球或区域尺度下的生态环境变化状况。分析植被覆盖时空动态变化特征及驱动力因素,对区域生态系统可持续发展具有重要意义。本文利用归一化植被指数(NDVI)作为指标,研究2000—2019年河南省植被时空动态变化特征,基于地理探测器模型分析河南省植被的空间异质性及其驱动力,并通过Hurst指数分析植被的未来趋势。结果表明:2000—2019年河南省NDVI整体呈现波动上升趋势,增长速度为0.01610 a^(-1),其中2009—2019年增长速度减缓并出现减小趋势;土壤类型、土地利用类型、GDP和人口密度4类因子对NDVI空间分布的影响程度最大;单一因子影响力均低于任两个因子的交互解释力,其中,自然和人为因子的交互作用对NDVI空间分布有明显的影响;由Hurst指数分析发现,河南省未来NDVI变化呈现反可持续性特征,Hurst指数<0.5区域占整个研究区域的植被覆盖度百分比为58.3%,整个研究区未来主要呈现下降趋势。

As the main body of the terrestrial ecosystem,vegetation cover can effectively reflect the ecological and environmental change at global or regional scale.It is of great significance to analyze the spatiotemporal variations and driving factors of vegetation cover for regional ecosystem sustainable development.We used the normalized vegetation index(NDVI)to explore the temporal and spatial variations of vegetation in Henan Province from 2000 to 2019.The spatial differentiation characteristics and driving force of vegetation in Henan Province were analyzed by Geodetector model,and the future trend of vegetation was explained by Hurst index.The overall vegetation index in Henan Province showed a fluctuating upward trend from 2000 to 2019,with a growth rate of 0.01610 a^(-1).The growth rate during 2009-2019 showed a decreasing trend.Soil type,land use type,GDP and population density greatly affected the spatial distribution of NDVI.The interaction of any two factors exceeded the influence of a single factor,and the interaction of natural and human factors had a significant impact on the spatial distribution of NDVI.Based on the analysis of Hurst index,we found that the future NDVI changes in Henan Province showed antisustainability characteristics,the area with Hurst index<0.5 accounted for 58.3%of the vegetation coverage in the whole study area,and the whole study area mainly would show a decreasing trend in the future.