| As a hot topic in ecohydrological research,the dynamic change of vegetation cover is affected by regional climatic factors and human factors.The influence of climate factors on vegetation change in a region is relatively slow,and it takes a long time to feel the difference of vegetation growth brought by natural factors.However,the impact of human activities on vegetation is more subjective and emergent,which may have a strong impact on regional vegetation in a relatively short time.Therefore,it is of great practical significance for regional ecological protection and high-quality development to correctly understand the spatio-temporal evolution of vegetation cover over long time series and quantitatively reveal the impacts of climate change,human activities and their interaction on vegetation cover.In this paper,the closed Tangbai River Basin is selected as the study area.Based on the MODIS NDVI data of the growing season from 2000 to 2019,combined with DEM,temperature,precipitation and other basic data,the temporal and spatial evolution characteristics of vegetation in the Tangbai River Basin are comprehensively analyzed,and the interaction between NDVI and the main influencing factors is studied and analyzed.The influence mechanism of regional vegetation variation and its driving factors on different spatial and temporal scales was revealed.The main research contents are as follows:(1)Study the temporal and spatial variation characteristics of vegetation cover in the Tangbai River Basin.Based on the NDVI data,temperature and precipitation data of the growing season of the basin from 2000 to 2019,the vegetation cover change law of the long series on the spatio-temporal scale was studied by Theil-Sen Median trend analysis and Mann-Kendall test,and the vegetation cover change characteristics of the Tangbai River Basin in recent years were revealed.(2)Analyze and predict the change trend of vegetation cover in Tangbai River Basin in the future.Based on the spatio-temporal variation of vegetation cover in the basin,the Hurst index was used to analyze the variation trend of NDVI.(3)To explore the response of vegetation cover change to climate factors in Tangbai River Basin.The trends of temperature and precipitation in different time and spatial scales were analyzed.The correlation between vegetation NDVI and major climate factors was analyzed by path analysis method.(4)Explore the response of vegetation cover change to human activities in the Tangbai River Basin.The residual analysis method was introduced to separate the response part of climate to vegetation growth without considering other non-major determinants.The residual difference between NDVI value and the real value was obtained from the analysis,so as to explore the role of human activities in the process of vegetation growth. |
