| As the spatial carrier of ecosystem,land is closely related to human beings.Its utilization and cover pattern have a profound impact on the sustainable development of regional ecological environment.As an ecologically sensitive area,Datong County has been experiencing accelerated and more complicated changes in land use and vegetation coverage since the beginning of the 21st century under the combined action of rapid socio-economic development and ecological civilization.This paper aims to clarify the dynamic change characteristics of land use and vegetation cover in Datong County,reveal the internal driving factors,and evaluate the ecological value,so as to provide scientific and theoretical support for the coordination of land use mode and eco-environmental construction.In this study,Datong County is selected as the research area,with 2001-2017 as the research period.Through remote sensing and GIS technology,the author extracted the spatial image data of land use status and vegetation coverage in Datong County,and analyzed the characteristics of land use change by using dynamic change model and landscape pattern.In addition,the author also used spatial analysis tools to explore the spatial-temporal differentiation of vegetation coverage,and the value equivalent method of unit area to evaluate the ecosystem service value,thus obtaining the following main conclusions:(1)During the study period,the comprehensive land use dynamic degree in Datong County showed a downward trend,and the degree of land use change weakened.As the dominant land use type,its forest land and sparse forest land had the characteristics of mutual transformation.Moreover,as the total amount of construction land in Datong County was small and changes drastically,its land use was in an unbalanced one-way increasing state,and large-scale cultivated land and ecological land were converted into construction land.Due to its limited economic growth,Datong County showed a relatively low degree in land use,and a higher degree in landscape fragmentation,and a gradually enhanced patch heterogeneity in unit space.Therefore,socioeconomic development is the core driving force of land use.With the adjustment of industrial structure and the implementation of environmental policies in the research area,the land use pattern in Datong County has undergone drastic changes during the research period.(2)Datong County boasts a sound vegetation coverage,which in most areas is above the middle height(?)and height(?).However,there are significant differences in the temporal and spatial variation trend when the vegetation coverage levels varies.The changes of vegetation coverage in the middle height(IV)and height(?)areas are relatively severe,showing a decreasing trend,and that in the low(?),middle low(?)and middle(?)areas fluctuates slightly,showing in an inverted "V" shape with the differentiation of altitude.As the altitude first increases and then decreases,the regions with high vegetation coverage are mainly distributed in the slope zone with a relatively steep slope.The vegetation coverage of the overcast slope is better than that of the overlying slope,indicating that the overcast slope in the study area is more conducive to the growth of vegetation.(3)The total value of ecosystem services in Datong County in 2001,2009 and 2017 was 13.805 billion yuan,14.809 billion yuan and 15.220 billion yuan respectively,showing an overall increasing trend.The ranking result of ecosystem service value is climate regulation>hydrology regulation>soil conservation,>biodiversity>gas regulation>environmental purification>aesthetic landscape>raw material production>food production>water supply>nutrient cycle maintenance.In conclusion,forest land is the land use type with the highest ecological sensitivity index.For every 1%increases in its ecological value coefficient,the total value will increase by more than 0.6%. |
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