延河流域植被格局演变及其驱动机制研究OA北大核心CHSSCDCSTPCD

The Yanhe River Basin,located in the loess hilly and gully area,has a fragile ecological environment and ex-ists serious soil erosion.In order to explore the characteristics of vegetation pattern changes and potential drivers in the Yanhe River Basin since the implementation of the policy of returning farmland to forest and grassland,this study uses trend analysis,coefficient of variation,Hurst index analysis and geographic detector to explore the temporal and spatial e-volution,dynamic stability and future sustainability of vegetation pattern in the Yanhe River Basin,and then analyzes the relationship between the vegetation pattern and natural and human factors.The results show that in the past 20 years,the normalized differential vegetation index,(NDVI)in the Yanhe River Basin showed a significant increase trend,and the spatial pattern showed the distribution characteristics of"high south and low north",and specifically,the vegetation in the middle of the Yanhe River Basin showed a very small area downward trend,accounting for only 0.06％of the basin area.The areas with relatively stable NDVI were mainly distributed in the southern part of the basin,the higher fluctuation areas were scattered in the Ansai area,and most of the other study areas were with medium and low fluctuations.In most areas of the basin,NDVI showed a continuous and significant increase trend.Compared with temperature,precipitation and NDVI showed a more significant positive correlation,which is the limiting climatic factor for vegetation increase in the Yanhe River Basin.The implementation of a series of ecological policies such as returning farmland to forest and grassland has improved the vegetation coverage of the region to a certain extent.The research results have important theoretical guiding value for the sustainable restoration of vegetation and ecological environment improvement in the Yanhe River Basin in the future.