Spatial-temporal Change Of Ecosystem Service Function And Analysis Of Ecosystem Service Value In Qilian Mountains

Qilian Mountain is an important ecological zone in arid and semi-arid areas in northwest China,with abundant ice and snow water resources.The Qilian Mountains span Qinghai and Gansu provinces from north to south and extend for more than one thousand kilometers from east to west.The ecological system of Qilian Mountains is composed of forests,grasslands,alpine glaciers and snow,it is the origin of inland rivers Shiyang River,Heihe River and Shule River,which is of great significance to the formation and development of oasis.At present,the warming of Qilian Mountains,the rise of snow line and the decrease of snow cover area make the Qilian mountains appear the phenomena of glacier degeneration,forest quality decline and ecological environment deterioration.With the progress of society and the development of science and technology,people gradually realize that the maintenance and protection of ecosystem services is of great significance for their long-term development.Ecosystem service function of quantitative study,through research data can be intuitive to make people aware of the importance of protecting our ecosystem,guiding people's scientific development of the natural environment resources and achieve the sustainable use of natural resources and environment and sustainable development between economy and also for maintenance,service and management of ecosystem provide theoretical basis and better service.Based on ArcGIS platform,InVEST model can quantitatively obtain the spatial distribution status of the corresponding ecosystem service functions by inputting the required spatial data,which is conducive to more convenient and more intuitive analysis of the spatial distribution characteristics and spatial changes of the ecosystem service functions.In this paper,Qilian mountain in the northwest arid region was taken as the research area.Based on GIS and ENVI technology,the land use type/cover changes in 1990,2000 and 2016were studied,and then the water yield,habitat quality and the ecosystem service function of carbon storage in the two periods of 1990-2000 and 2000-2016 were evaluated using InVEST model.On this basis,the ecosystem service value indicator system(ESSVI)is established to make a dynamic evaluation and hot spot analysis of the ecosystem service value of Qilian Mountains.Conclusion as below:(1)From 1990 to 2000,the area of grassland and agricultural land increased significantly,moderate coverage of grassland area increased by 4827 km~2,bare rocky gravel,marshland,permanent glacier snow and shrub area decreased,respectively,loss 5299 km~2,1694 km~2,707 km~2,351 km~2.(2)In 1990,2000 and 2016,the maximum water production per unit area of Qilian Mountain reached 621.56 mm,679.06 mm and 487.92 mm respectively.(3)From 1990 to 2000,the habitat quality of Qilian Mountain continued to deteriorate,and the habitat degradation index increased from 0.06 to 0.068.From2000 to 2016,the degradation of ecological environment quality intensified,and the habitat degradation index increased from 0.068 to 0.154,an increase of 26.5%.(4)The total carbon storage in Qilian Mountain is abundant.The total carbon storage in Qilian Mountain in 1990,2000 and 2016 was 5.41×10~8 t,5.49×10~8 t and5.69×10~8 t,respectively.Carbon storage increased by 2.8×10~7 t in 26 years,with an average annual growth rate of 3.8%.(5)From 1990 to 2016,the mean value of ESSVI in Qilian Mountains experienced a process of gradual improvement and continuous improvement.The regions with low ecosystem service value were mainly distributed in the west and south.In 1990,the area with excellent and good ecosystem service value accounted for 48%of the total area.In 2000,the area occupied by the two accounted for53.88%.In 2016,the proportion of good and excellent increased to 70.26%,and the area above good increased by 40458.65 km~2 in 26 years.(6)The hot spots of ecosystem service value in Qilian Mountains mainly correspond to woodland,shrubbery,open woodland,grassland,dry land and marsh.Cold spots are mainly distributed in the gobi desert,saline-alkali land,bare land and other unused areas.From 1990 to 2016,the area of hot spots of ecosystem service value in the Qilian Mountains has been increasing and transferring to the central region.After 2000,the change of ecosystem service value was larger than that of the previous decade.