Evaluation Of The Value Of Ecosystem Services In The Weihe River Basin Based On The GIS-based Equivalent Value Improvement Method

Ecosystem service value(ESV)is making services value,which can promote the survival and development of human beings,provided by ecosystem structure and processes directly and indirectly to humans.It can indirectly reflect the impacts that climate and land use change on ecosystem services.It is an important index to reflect the effect of human activities on ecosystem services.Taking the Wei River Basin as the research object,the value of ecosystem service is calculated which is guiding significance to the future human activities in the region.Since 1990s,researchs on ecosystem services have gradually become the focus of global researchs.The research on ecosystem service value is also flourishing.To estimate the ESV mainly includes two kinds of methods.They are functional value method based on the value of unit service function and equivalent factor method based on the equivalent of unit area value.In this paper,based on the method of unit equivalent value,the value of each service function of ecosystem is accounted in Wei River Basin.The main conclusions are as follows:(1)The comprehensive harnessing measures of returning farmland to forest and grassland have promoted the scientific utilization of land use and promoted the recovery and development of land use in the basin.With the development of urbanization,the construction land is increasing.In the early stage of the implementation of the measure,the area of land use type changed dramatically,and the dynamic degree was larger.In the later stage,that is the consolidation period,the amount of land use conversion decreased,and the single dynamic degree and the comprehensive dynamic degree decreased,and the disturbance index of ecosystem to human is decreasing year by year.The results show that the land use change tends to be relaxed and the utilization mode is stable,and the degree of human intervention continues to weaken.(2)The sensitivity of ESV to VC is accounted by using the model of sensitivity index,show that the VC based on the improved equivalent value method is reliable.Based on the three factors of temporal and spatial adjustment of NPP,the mount of precipitation and soil conservation,obtain the spatio-temporal dynamics VC.They are estimated about 9 kinds of ESV of different ecosystem on this basis in Wei River Basin, and the ESV of this study is proved to be scientific and valuable.(3)During the period of 2000-2010,the total ESVof Wei River Basin which is estimated by the improved equivalent value method,shows the annual change characteristics of the first decrease and then increase,and having obvious annual variation characteristics.Except 2000,the ESV is mainly concentrated in summer,less in winter.The value of H-H mainly concentrated areas in Qinling Mountains,Taibai Mountain,six Panshan,Ziwuling,Huanglong Mountain etc.,the value of L-L is mainly distributed in the Guanzhong Region.The ESV of 2000 had a strong randomness and heterogeneity,and the spatial autocorrelation and aggregation were significant in the year of 2005 and 2010.The characteristics of the time is relate to the implementation of returning farmland to forest and grassland and the comprehensive management of the Wei River Basin.In the summer,the combination of rainfall and heat is good,the biological growth is luxuriant,the more of biomass,the bigger of ESV.Meanwhile,the spatial characteristics are relation to the topography,the climate,the water resource and so on.Furthermore,it proved that the equivalent value method of time and space adjustment is applicable in Wei River Basin.(4)There were significant differences in ESV,individual ESV and unit area ESV supply capacity provided by different land use types,and the contribution rate of ESV variation is different.The total ESV size relationship in 2000 was Woodland>Cultivated land>Grassland>Waters>Unused land.The total ESV size relationship in 2005 and 2010 was Woodland>Grassland>Cultivated land>Waters>Unused land.The single ESV has obvious regional and temporal characteristics,and presents different characteristics in different ecosystems.Characteristic of ESV supply capacity per unit area is Waters>Woodland>Grassland>Cultivated land>Unused land.There was significant correlation between land use type and ESV.The results show that the contribution rate of the ESV variation is Woodland>Cultivated land>Grassland>Waters>Unused land.That is,the change of Woodland ESV has the greatest effect on the total ESV in the study area,and the influence of the unused land is the least.(5)There are tradeoffs and synergies between the different ecosystem services.There are tradeoffs between the supply of services and regulatory services,support services,cultural services,and there are tradeoffs and synergies between the single function of the four services.For example,the function of biodiversity conservation was opposite to that of soil formation and maintenance,the function of food production provided by the farmland ecosystem and the supply of raw materials provided by the forest ecosystem are decreasing year by year,and climate regulation and gas regulation function showed a synergistic relationship.There is great influence of land use on the resulting ESV.(6)The ES V of the Wei River Basin shows different characteristics of temperature,precipitation,Landuse,NPP and altitude distribution.The correlation between single ESV and temperature and precipitation is higher than that of comprehensive ESV.The correlation between the value of ecosystem services and the areas of land use is restricted by land use pattern.The correlation between comprehensive ESV and NPP is significant.The distribution of high and low values of ESV,the distribution area and the sparse distribution area change with altitude,the lowest and highest values are distributed in the plain and valley areas with the lowest elevation,1000-1800m altitude is a centralized distribution area of ESV.