Spatio-temporal Changes And Influencing Factors Of Land Use And Vegetation Cover In The Ten Tributaries In The Yellow River Basin From 1986 To 2020

Ten tributaries is a typical ecologically fragile area in Jiziwan（n-shape bent）region of the Yellow River,and studying the changes in land use and vegetation cover has profound implications for resolving the conflicts between humans and the environment in the region.In this study,remote sensing images of the Ten kongdui basins from 1986,2000,2010,and 2020 were obtained,and combined with meteorological,topographical,socio-economic data,the Arc GIS 10.2 and ENVI 5.3 software were utilized to analyze the spatiotemporal characteristics of land use changes,spatiotemporal characteristics of vegetation cover changes,and the differences in influencing factors at temporal and spatial scales,aiming to provide data support for ecological restoration in the Yellow River region.The main research findings are as follows:（1）By 2020,forestland has become the dominant land type in Ten tributaries,covering an area of 6308.43 square kilometers,accounting for 60%of the total study area.Over the past 35 years,the degree of land use change has been more significant in the period from 2010 to 2020 than in the periods from 2000 to 2010 and 1986 to 2000,and the significant changes in land use types mainly occurred between 2010 and 2020.（2）Regarding land use transfer areas,the increase in forestland mainly came from the conversion of unused land and grassland.The largest outflow of land was from unused land,with a cumulative outflow of 2926.37 square kilometers over the past 35years.In terms of spatial distribution of land use transfer,most of the conversions from unused land to forest and grassland occurred in hilly areas and sandy areas.In the past 10years,forestland in the southeastern part of the hilly area has been converted to construction land,primarily verified through field visits as conversions to urban-rural industrial and mining construction land.（3）The overall vegetation coverage has shown a stable increasing trend over the past35 years,with high vegetation coverage reaching 1344.73 square kilometers by 2020,accounting for 12.68%of the study area,and medium to high vegetation coverage reaching 1234.59 square kilometers,accounting for 11.64%of the total study area.In terms of changes in vegetation coverage,significant improvements have mainly occurred in the eastern part of the sandy area and the southeastern part of the hilly area over the past 35 years.（4）Vegetation coverage and land use changes are influenced by climate,topography,policies,economy,and population.In the plain area,due to flat terrain,population growth,and economic development leading to an increase in construction land,there has been a slight decrease in arable land area,resulting in a decrease in vegetation coverage during this period.In the sandy area,influenced by policies and climate,unused land has been converted to forest,grassland,and arable land,resulting in an increase in vegetation coverage.In the hilly area,influenced by policies and climate,the area of forest and grassland has continuously increased,leading to an increase in vegetation coverage,while a small portion of forestland has been converted to urban-rural industrial and mining construction land due to economic development.（5）According to the principal component analysis,the driving factors of land use changes in the Ten tributaries over the past 35 years can be summarized as economic factors and productivity factors.The regression equation for the two principal components is Y=0.268Z1+0.075Z2+1.06×10^-15.Based on the grey relational analysis,over the past 35 years,the changes in forestland and grassland were significantly influenced by climate factors from 1986 to 2010,while from 2010 to 2020,the changes in forest and grassland were primarily driven by the development of industrial and construction sectors.Changes in the arable land area were mainly influenced by population and agricultural productivity factors,while changes in construction land were influenced by population changes and the development of industrial and construction sectors.Unused land and water bodies were strongly influenced by climate,and in addition,unused land was also influenced by agricultural productivity.