Impact Of Land Use And Vegetation Coverage Change On Ecosystem Service Value In Tarim River Basin

The Tarim River Basin is located in the arid region of northwest my country.In recent years,with the socioeconomic development of the basin and the impact of global climate change,the various land use types in the basin have frequently changed,a large amount of vegetation has degraded,and the allocation of water resources has become seriously unbalanced.The ecological environment in this area is gradually deteriorating,which hinders the construction of ecological civilization in this area.This paper mainly explores the temporal and spatial evolution of land use change,normalized vegetation index(NDVI)and ecosystem service value(ESV)in the Tarim River Basin,and quantifies the impact of land use and normalized vegetation index change on the increase and decrease of ecological assets.The conclusions are as follows:(1)From 1990 to 2018,the evolution trend of the land use pattern in the Tarim River Basin showed that the area of cultivated land,high-coverage grassland,construction land,and unused land increased,and the middle-covered grassland,low-coverage grassland,woodland and water areas showed a downward trend.The area of arable land increased by 181.60×10~4 hm~2,unused land increased at a rate of 4.26×10~4 hm~2/a,high coverage grassland increased by 88.64×10~4 hm~2,and medium coverage grassland decreased by29.89×10~4 hm~2 during the study period.The low-coverage grassland decreased by 246.33×10~4 hm~2,and the water area decreased at a rate of 4.24×10~4 hm~2/a.(2)The NDVI of natural vegetation in the Tarim River Basin showed an overall increasing trend from0.125 in 2000 to 0.133 in 2018.Due to the wide distribution and large area of no-vegetation coverage and low-vegetation coverage in the basin,the increasing trend was not obvious.The NDVI of the natural vegetation in this watershed has a spatial distribution characteristic of"high in the north and low in the south",and only the type area of 0<NDVI≤0.2 showed a decreasing trend,while the area of other types showed an increasing trend.(3)Based on the estimation of ecosystem service value in the Tarim River Basin from 1990 to 2018,it isfound that the overall ecosystem service value of the basin presents a downward trend.And through the analysis found that basin ecosystem service value increase or decrease is mainly affected by the basin to increase or decrease of cultivated land,grassland and water area.The contribution rate of the water area change is 66.96%,which is the main reason for the loss of the ecosystem service value of the watershed.In the study of comparing the changes of vegetation with different coverage to the ESV changes of the watershed,it was found that the contribution rate of 0<NDVI≤0.2 was 59.02%,which was the main driving force for the changes in the ESV of natural vegetation in the basin.