| Accurate assessment and response analysis of land-use-and-land-cover(LUCC)change and Ecosystem Service Value(ESV)are of crucial importance to regional ecological security and economic development.Yinchuan City,the capital city of Ningxia Hui Autonomous Region,is one of the first 20 pilot cities for urban design in China.With the implementation of both reform and opening-up and the strategy for development of western China,the urban space of Yinchuan City has expanded obviously,and problems between people and land becomes serious.This places much pressure on the fragile ecological environment of Yinchuan City.A study of landscape pattern and ESV in Yinchuan City will help us to understand the change of ecological security in local cities and provide insight into the realization of harmonious development between land and man.The current study targeted eight sets of LUCC data of Yinchuan City obtained in the year of 1980,1990,1995,2000,2005,2010,2015 and 2020.Specifically,the spatial-temporal change of landscape pattern in Yinchuan City was analyzed by taking into the land use transfer matrix,dynamic attitude index and various landscape indices.Based on such analyses and the improved equivalent factor,ESV and the law of spatio-temporal change were comprehensively analyzed.Meanwhile,Geo Detector was also introduced to quantitatively detect the driving mechanism of spatio-temporal change of ESV in Yinchuan City.Models were improved to simulate and predict the trend of land use in Yinchuan City and the development direction of the city in the next few decades so as to provide scientific basis for the urban expansion and planning of Yinchuan City.Main findings of the current research are as follows:First,the landscape pattern of Yinchuan City changed significantly in the past 40years.The area of bulid-up land increased by 538.908 km~2,accounting for 7.2%of the total area of Yinchuan City.Grassland and bare land showed a decreasing trend,while forest land and water body remained stable.Build-up land increased significantly since 2010,especially the time from 2015 to 2020 witnessing the fastest growth rate and accelerated urbanization.The conversion of grassland and bare land for both the build-up and cultivated purposes was the typical characteristics of land use during this period of time.From 1980 to 2020,the heterogeneity,diversity and evenness of landscape in Yinchuan City increased,landscape types became more and more complex,the spatial connectivity of bulid-up land became better,and the urban developmental layout of Yinchuan City became more reasonable.Largest Patch Index,Interspersion and Juxtaposition Index,Shannon’s diversity Index,landscape shape index and Contagion Index were able to reveal the spatial changing characteristics of both land use and landscape patterns in Yinchuan City.The habitat quality index in Yinchuan City showed a downward trend from 1980 to 2020,indicating that the habitat quality in Yinchuan City was downward in recent years.Second,in recent 40 years,the total ESV value regarding the types of land use in Yinchuan City decreased by 0.597 million yuan.The ESV of grassland,cultivated land,forest land and water body showed obvious increase and decrease,and the ESV of bare land remained stable.During 1980-1995,the ESV of grassland,water area and cultivated land increased significantly,and such increase became gradually small.The ESV of the eleven secondary ecological service types varied,while the ESV of biodiversity,soil conservation,environmental purification,aesthetic landscape,raw material production and nutrient cycle maintenance remained unchanged.In addition,the ESV of hydrology regulation,climate regulation,gas regulation,food production and water resource supply experienced significant changes.The change rates of ecosystem services(ESV_f)values in different areas of Yinchuan City were different.The ESV values of food production,gas regulation,climate regulation and nutrient cycling decreased significantly,while ESV_f of aesthetic landscape increased significantly.From 1980 to 2020,ESV in Yinchuan City showed significant low-low and high-high agglomeration,and the overall spatial agglomeration degree showed a downward trend.The analysis of cold and hot spots of ESV changes showed that the coordination and balance of ecological development in Yinchuan City were affected.Third,for the single factor that drove the change of ESV in Yinchuan City,GDP is the most significant factor,what was followed by temperature and elevation.The interaction between GDP and other factors was significantly greater than the driving force between other factors.That is,the ESV in Yinchuan City is influenced by the interaction among many factors.Temperature,elevation and GDP were the main driving force for supply service,regulation service,support service and cultural service,while temperature and elevation were the second driving force for these factors.Normalized Difference Vegetation Index(NDVI)was most widely used to reflect the vegetation coverage.Grass was the dominant vegetation in Yinchuan City city.The ecosystem service value equivalent of grassland per unit area was low.This may result in high vegetation coverage but low ESV.From 2000 to 2020,the spatial variation trend of GDP and NDVI in Yinchuan City was in good consistency with the spatial variation of ESV,showing the spatial characteristics of high-high and low-low agglomeration,and GDP and NDVI were the main dynamic driving factors.Fourth,in the condition of unconstrained scenarios,compared with that in 2020,the area of cultivated land,forest land,grassland and bare land in Yinchuan City in2030 will decrease,while the area of water and bulid-up will increase,and the area of bulid-up land will increase the most.Under the constraint of the red line for ecological protection,the area of cultivated land,grassland and bare land will decrease in Yinchuan City in 2030,while the area of bulid-up land will increase.In the scenario of unconstrained development,the degree of newly-added urbanization become obvious in the central and northwest part of Yinchuan City in 2040,and the direction of urban land expansion will take place mainly along the north-south vertical line,on which Helan and Yongning County develop from the direction of fragmented urbanization to the direction of centralized integration,showing a trend of cluster development.Under extreme environmental protection scenarios and moderate environmental protection scenarios,the requirement for the protection of cultivated land,forest land and grassland are strict.This will greatly restrict the urbanization process.Under moderate environmental protection scenario,the probability of new urban pixels expansion to grassland is 60%.Compared with the unconstrained development scenario,the newly added pixels in the cultivated land protection scenario decreased by nearly 50%,and the decrease of urbanization pixels mainly come from the cultivated land area.Under the ecological red line protection scenario,the probability of medium-high urbanization is 54.58%. |
PDF Full Text Request