Spatial-temporal Changes And Trade-offs Of Ecosystem Services In Shaanxi Province

The core of ecosystem research is ecosystem service,which is of great significance to the rational allocation of natural resources and the effective protection of ecological environment.There are various types of ecosystem services.Most of the different ecosystem services are trade-offs/synergies and compatible.Due to the increase of human activity intensity and population,human demand for ecosystem has increased,resulting in insufficient supply capacity of ecosystem,and leading to the degradation of ecosystem functions.Shaanxi Province is located in the northwest of China,in a key position of opening to the west and"the Belt and Road".There are complex and diverse of landform and climate types,the natural endowments of different regions vary greatly,with strong spatial heterogeneity.It is a typical representative area for studying the spatiotemporal changes and trade-offs/synergies of ecosystem services.This paper used multi-source data such as meteorological data,land use/cover data,NDVI data,DEM data and socio-economic data,based on the RUSLE,CASA and In VEST model,the four ecosystem services of soil conservation,net primary productivity(NPP),habitat quality and water yield were evaluated,and the spatiotemporal change patterns were analyzed in Shaanxi Province from 2000 to 2020,SPSS software is used to identify the trade-off/synergy relationship of ecosystem services,which is under different spatial scales.The main influencing factors and degree of ecosystem services are based on the geographic detector model,in order to provide scientific decision-making for the effective use and management of natural resources in Shaanxi Province.The main conclusions are as follows:(1)Spatiotemporal changes of ecosystem services.Soil conservation、habitat quality and water yield increased first and then decreased,the annual mean values of soil conservation were 339.80 t/hm~2、82.00 t/hm~2 and 59.36 t/hm~2,the annual mean values of habitat quality were 0.577、0.583 and 0.580,the annual mean values of water yield were 442.39mm、659.93mm and 448.06mm,NPP increased gradually with annual averages of 488.27 g·C/m~2、585.69 g·C/m~2 and 678.54 g·C/m~2 from 2000to 2020.In terms of spatial distribution,the high value areas of soil conservation were concentrated in the south of the study area,and the low value areas were distributed in the middle and north;The high value areas of NPP and habitat quality are concentrated in the south and north,while the low value areas are distributed in the middle and north;The high value area of water yield is concentrated in the south,and the low value area is distributed in the north from 2000 to 2020.(2)Trade-offs/synergies of ecosystem services.The relationship between soil conservation and NPP,habitat quality and water yield in the study area showed stable synergy on the global scale from 2000 to 2020.The relationship between NPP and habitat quality mainly showed synergy.The relationship between water yield and NPP,habitat quality showed stable trade-off.The correlation coefficient between various ecosystem services changed little over the years.In addition,there is obvious scale effect in trade/synergy relationship of the four ecosystem services,which is significantly different in the whole region,city and river basin scales.(3)Ecosystem service hotspots.According to the distribution of multiple hot spots in the study area,the Class 1 hot spot accounts for the largest proportion,the non-hot spots accounts for the smallest proportion.The non-hot spot decreased,distributed in the north-central;the Class 1 hot spot increased,mainly distributed in the middle and north;the Class 2 hot spot increased,mainly distributed in the south and middle,the Class 3 hot spot increased,mainly distributed in the south and middle;the Class 4 hot spot decreased,mainly distributed in the south from 2000 to 2020.(4)Factors affecting ecosystem services.Based on the geographic detector model,it can be seen that the main factor affecting the spatiotemporal variation of soil conservation,NPP and water yield is precipitation,and the degree of impact on different services is also different.Habitat quality is mainly affected by vegetation coverage,followed by human interference.Regional ecological management decisions were supported by integrating ecosystem service trade-offs/synergies and their scale effects.