| Land use change is an important cause of global ecological evolution,and the study of land use change and ecosystem service value(ESV)change is of great significance in maintaining regional ecological security and exploring the coordinated and sustainable development of regional ecology and economy.As a densely populated and highly intensive land-use area,the development and construction of large river basins have an important impact on regional sustainable development.The Yellow River Basin has an important position in the construction of ecological civilisation in China,but its ecological environment is extremely fragile.In recent years,with the accelerated urbanisation and increasing human activities,it has led to an unreasonable land use structure and a continuous deterioration of the ecological environment quality of the basin.In order to reveal the impact of land use changes on ESV in the Yellow River Basin and accelerate the achievement of national strategic objectives for ecological protection and high-quality development in the Yellow River Basin,this study,with the support of Arc GIS 10.5,based on land use data of the Yellow River Basin for four years 1990,2000,2010 and 2020,uses methods such as land dynamic attitude and transfer matrix to analyse the number and dynamic changes of land use area in the basin for three decades based on this analysis,the spatial and temporal distribution characteristics of the ESV per ground of 73 prefecture-level cities were analysed.A sensitivity analysis was conducted to test the accuracy of the ESV measurement results,to verify the influence of value coefficients on ESV,and to further understand the extent to which ESV varies with the ES value coefficients of each land type.The PLUS(Patch-generating Land Use Simulation Model)model was used to simulate the land use distribution patterns of the Yellow River Basin in 2030 under natural development,cultivated land protection and ecological protection scenarios,and to compare the differences in total ESV in the basin under different scenarios.Finally,the hotspot analysis was used to explore the spatial and temporal distribution of cold and hot spots of ESV per ground of the Yellow River Basin,so that conservation recommendations can be made in the context of the upper,middle,and lower reaches of the basin.The specific conclusions are as follows:(1)During the period from 1990 to 2020,the proportion of various types of land in the Yellow River Basin changed slightly,with grassland,unused land,and cultivated land still being the main areas,followed by forest land,and the proportion of water area and built-up land being the smallest.The area of forest land,grassland,water area,and built-up land showed an increasing trend,while the area of cultivated land and unused land showed a decreasing trend.From the perspective of the transfer matrix,the transformation between different categories in the Yellow River Basin was more intense during the two time periods of1990 to 2000 and 2010 to 2020.From the perspective of land dynamics,the comprehensive land use change in the Yellow River Basin has gone through a process of from relatively severe to slow and then to relatively severe over time.(2)From 1990 to 2020,the total ESV of the Yellow River Basin showed a trend of first decreasing and then increasing,with an overall increase of 160.569 billion yuan during the study period,with an overall increase of 3.98%.In the ESV of the Yellow River Basin,ecological land such as forest land,grassland,and water area were the main contributors to the ESV,and their value changes were closely related to the changes in land types.From the perspective of spatiotemporal distribution,the ESV per ground of various cities in the Yellow River Basin showed a spatial distribution pattern of high in the middle reaches and low in the upper and lower reaches,and the areas with significant changes in the ESV per ground of cities in the basin during the study period were mainly located in the upper and lower reaches of the basin.Through sensitivity analysis,it was found that the sensitivity of each category is less than 1,indicating that the ESV lacks elasticity towards the value coefficient.This indicates that the ESV calculation results are reliable,and from the degree of impact of the value coefficient of each category on ESV,grassland>forest land>water area>cultivated land>unused land.(3)In the simulation of land use distribution patterns in the Yellow River Basin under different scenarios in 2030,the Kappa coefficient of the PLUS model was 0.976,which passed the accuracy test.Under the three scenarios predicted for the Yellow River Basin in 2030,the land use characteristics of the basin remain relatively stable,with grassland,unused land,cultivated land,and forest land as the main land types.But the area of various regions has undergone varying degrees of change,with the most significant change being in built-up land.Under different development scenarios,the focus on protection objectives is different,and the changes in land development are also different: under natural development scenario,built-up land significantly increases;The area of forest land and grassland has significantly increased under ecological protection scenario;Under the cultivated land protection scenario,the area of cultivated land has significantly increased.The ESV of each scenario shows an increasing trend compared to 2020.The total ESV of the ecological protection scenario is the highest among the three scenarios,and the increase in ESV is also the largest compared to 2020.From the perspective of ESV,ecological protection scenario has more reference significance for the development planning of future watershed land use patterns.(4)From the spatial distribution of urban ESV per ground in the Yellow River Basin,the distribution areas of cold and hot spots are roughly the same under the three scenarios.The cold spots are mainly concentrated in the upstream high plain,the Gobi desert area with sparse vegetation,and the ecologically fragile area at the junction of Henan and Shandong provinces in the downstream.Hot spots are mainly concentrated in areas with well-developed water systems and good ecological vegetation in the middle and lower reaches.The ecological protection of the Yellow River Basin requires precise regulation based on the characteristics of each region and local conditions.We need to strengthen the ecological protection and restoration efforts in upstream areas,and enhance the water conservation capacity;Preventing and controlling soil erosion in the middle reaches and improving soil and water conservation capacity;Save and intensive land use,alleviate the contradiction between cultivated land and built-up land in downstream areas.Overall,ecological land use is crucial for the ecological security of the upper,middle,and lower reaches of the basin.Therefore,in the future,it is necessary to strengthen the importance of ecological land use in the basin,and provide reference for the future ecological construction and built-up area expansion of th basin based on three development scenarios,in order to promote the acceleration of the national strategic goals of ecological protection and high-quality development in the Yellow River Basin. |
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