Analysis The Spatial-temporal Differentiation Of Ecosystem Services Value In Hongshui River Basin Of Guangxi

Quantitative research on ecosystem service value is of great significance to regional ecological compensation and social and economic development.The Hongshui River Basin in Guangxi is mainly located in the karst mountainous area of southwest Guangxi,which is rich in mineral resources,agriculture,climate,biology,tourism and other natural resources.However,the ecological problems such as rocky desertification and soil erosion are obvious.The study on the ecosystem service value of the region can provide decision-making reference for the watershed ecological compensation and the implementation of regional socio-economic development strategy.Based on landsat TM/OLI data,the classification data of Guangxi Hongshui River Basin in 2001,2006,2011 and 2016 were obtained by combining unsupervised classification with visual interpretation,and the NPP data of Guangxi Hongshui River Basin were obtained by using CASA model based on NDVI,annual mean temperature,annual mean precipitation,sunshine percentage and other meteorological data.Using ArcGIS and ENVI image processing software,spatial analysis method and comparative analysis method,the spatial and temporal changes of ecosystem service value in Hongshui River Basin of Guangxi were analyzed and studied,and the following conclusions were drawn.(1)According to the spatial distribution characteristics of ecosystem service value in 2016,the high-value areas of ecosystem service value are mainly distributed in Lingyun,Tiane,Bama,Fengshan and Jinchengjiang in the northwest of the study area.The low value area mainly distributes in Wuyi,Heshan,Binyang,Xiangzhou and Xingbin in the southeast of the study area.The highest value is Lingyun County,and its ecosystem service value is 19.699 billion yuan.The lowest value is Xingbin District,the value of ecosystem services is 10.727 billion yuan,and the value of ecosystem services is decreasing from southwest to northwest.(2)From the ratio of per capita ecosystem service value ESV to per capita GDP.Fengshan County,Leye County,Donglan County and Lingyun County have high ratio of per capita ESV to per capita GDP.The per capita ESV of these counties is more than 6 times of per capita GDP,which indicates that these counties have good ecological service function and low level of socio-economic development.The ratio of per capita ESV to per capita GDP is lower in Guiping,Xingbin,Binyang and Liujiang counties.The per capita ESV is less than 0.7 times of per capita GDP in these counties,which indicates that the socio-economic level is higher and the ecosystem service function is worse in these areas.(3)Analyzing the distribution of ecosystem service value in different grades of terrain undulation.With the increase of terrain undulation,the value of ecosystem services is also greater.Among them,the largest service function is regulation service,and its value accounts for more than 70%of the total value of the watershed service.The smallest service function is cultural service,and its value only accounts for 0.04%of the total value of watershed service.On the whole,the ecosystem service value of Hongshui River is regulation service>support service>supply service>culture service.(4)Temporal variation characteristics of ecosystem service value in Hongshui River Basin of Guangxi from 2001 to 2016.The total value of ecosystem services of Hongshui River increased year by year during the study period.This change is partly due to the implementation of policies such as returning farmland to forests from 2001 to 2016.The area of woodland ecosystem increased gradually during the study period.The area of grassland ecosystem has been reduced.The area of cultivated land ecosystem has been greatly reduced,which makes the ecology of the study area recover gradually.The total ecosystem service value of Hongshui River increases year by year with the increase of vegetation net primary productivity and vegetation coverage.(5)Analyzing the change of ecosystem service value.The highest value of ecosystem services in the four years were forested land,which accounted for more than 83%of the total value of ecosystem services in the study area.The lowest proportion of land is construction land and other land,which accounts for about 0.01%of the total ecosystem services value.From the perspective of ecosystem service value share,the ratio of ecosystem service value of each land type has little change from 2001 to 2016,and the change range is within 3%.From the aspect of ecosystem service value ratio,the order of ecosystem service value ratio from 2001 to 2011 is:woodland>grassland and cultivated land>water>construction land and other land.In 2016,the ratio of ecosystem services value was in the order of forest land>cultivated land,grassland and water>construction land and other land.(6)Analyzing the change of ecosystem service value per unit area.During the study period,the value of ecosystem services per unit area of Hongshui River increased year by year.In 2001,2006,2011 and 2016,the total value of ecosystem services per unit area in the Hongshui River Basin of Guangxi was 5.5189 million yuan/km~2,5.5689 million yuan/km~2,5.7953 million yuan/km~2 and 6.066 million yuan/km~2,respectively.According to the ecosystem service value per unit area of land,the water has the largest value of ecosystem service per unit area,and the construction and other land has the smallest value of ecosystem service per unit area.The order of service value per unit area in Hongshui River Basin was water>forest land>grassland>cultivated land>construction and other land.