2001-2018年黄土高原植被覆盖人为影响时空演变及归因分析

基于2001-2018年的MODIS-NDVI和MODIS-LST以及土地利用、交通、人口等多种人文社会数据,通过温度植被干旱指数反映黄土高原土壤水分状况,利用残差法剔除土壤水分得到植被覆盖变化的人为影响,辅以趋势分析、Hurst指数、地理探测器等方法探讨了黄土高原植被覆盖的人为影响变化特征、未来变化趋势以及人为影响的归因。结果表明:(1)黄土高原2001-2018年植被覆盖人为影响变化趋势为0.36×10-2 a-1,人为对植被覆盖的影响向正作用方向发展。(2)黄土高原植被覆盖人为影响的未来变化趋势由正作用转为向负作用方向发展,值得注意的是退耕还林重点实施区植被覆盖的人为正作用未来变化呈减弱趋势。(3)综合相关分析与地理探测器结果,确定影响植被覆盖变化的人为主导因子主要包括高级别旅游景点、城市分布、交通和土地利用。(4)未来退耕还林工程的实施以及生态建设工程的维持,应在注重城市经济发展的同时重视生态建设,减缓交通业对生态环境所带来的危害,加强绿色旅游业发展以及减缓土地变化等人为活动的影响。

Spatio-temporal evolution and attribution analysis of human effects of vegetation cover on the Loess Plateau from 2001 to 2018

The Loess Plateau is one of the four major plateaus in China.It is the most concentrated and largest Loess area on earth,but fragile ecology,which feeds 8.5%of China’s population with 6.7%of the land.The longterm population and economic development pressure have caused severe regional ecosystem degradation.Since the implementation of the project of returning farmland to forest and grassland in 1999,the vegetation construction acceleration has led to significant improvements in the ecological environment.However,the manmade factors and the influence rules of vegetation cover changes on the Loess Plateau still lack several quantitative demonstrations.Therefore,strengthening the quantitative analysis of the human impact on the regional ecological environment will not only promote accurate ecological restoration,but also promotes the construction of human stability,harmony,and happy life,which has important theoretical and practical significance.Based on the MODIS-NDVI and MODIS-LST from 2001 to 2018,as well as various humanistic and social data,such as land use,transportation,and population,this paper constructs the Temperature Vegetation Dryness Index(TVDI)to reflect the soil moisture status of the Loess Plateau.The residual method is used to remove soil moisture to express the manmade influence of vegetation cover.The spatiotemporal evolution pattern of the man-made influence is analyzed with trend analysis and the Hurst index.We tend to explore the effect degree of various human factors,influence direction,and their temporal changes on vegetation coverage with geographic detectors and correlation analysis methods on the Loess Plateau.It is hoped to determine the manmade leading factors affecting the vegetation cover changes on the Loess Plateau,and provide a solid basis for the maintenance of the early ecological construction project and the future implementation of farmland to forest project,which will contribute to the healthy and sustainable development of the ecological environment of the Loess Plateau.The results are as follows:(1)The anthropogenic influence of vegetation cover on the Loess Plateau from 2001 to 2018 has a trend of 0.36×10?2 a?1,and the impact of human activities on vegetation cover was positive.(2)The future trend of human impact on vegetation cover will change from positive to negative on the Loess Plateau.It is worth noting that the positive effect of vegetation cover will weaken in the key implementation areas of returning farmland to forest.(3)According to the results of correlation analysis and geographical detector,the main human factors affecting vegetation cover change include high-level tourist attractions,urban distribution,transportation,and land use.(4)The future implementation and maintenance of the returning farmland to forest project should pay attention to reinforce ecological construction at the same time as urban economic development,reduce the harm of traffic industry to the ecological environment,strengthen the development of green tourism and slow down the impact of human activities,such as land change.