The Study Of Spatial And Temporal Variation Of Water Production Function And Its Influencing Factors In The Hengduan Mountain Region Based On InVEST Model

Hengduan Mountain Region is not only an important ecosystem service function area in China,but also one of the areas with relatively concentrated water resources in China.It is located on the upper reaches of the rivers such as the Yangtze River,Jinsha River and Lancang River.Hengduan Mountain Region can provide sufficient water resources for residents in the local and downstream areas.Its water production function is of great significance for maintaining human welfare and ecological security.Due to the dual impacts of climate change and human activities,changes in runoff in mountainous areas directly affect the spatial distribution pattern of the water cycle and water resources.Therefore,it is of great significance to clarify the spatial distribution pattern,spatial-temporal variation and influencing factors of water production in the Hengduan Mountain Region for regional water resources protection and reasonable planning of water resources applications.This study was based on data from 62 meteorological station sites from 1985 to 2014,DEM data,soil data,and Land use data in 1990,2000 and 2010 in the Hengduan Mountain Region.The water production module in the In VEST model was applied to quantify the ecosystem water production functions in the Hengduan Mountain Region in 1990,2000 and 2010.On this basis,based on Arc GIS10.2 software,the spatial and temporal distribution characteristics of water production were analyzed,and the spatial and temporal differences of the water production changes were clarified.By establishing a linear relationship between water production,land use factors and climatic factors,the factors influencing the change in water production in the Hengduan Mountain Region were identified.The research results can provide a scientific reference for the rational utilization and sustainable use of water resources in Hengduan Mountain Region.The main conclusions are as follows:1.The water production of the ecosystem in Hengduan Mountain Region from 1990 to 2010 showed a trend of increasing first and then decreasing,and the water production capacity in 2010 did not return to 1990 levels.Volumetric water production in 1990,2000,and 2010 was 193.784 billion m3,206.779 billion m3,and 172.331 billion m3,respectively.The average water production was 446.03 mm,475.94 mm,and 396.67 mm,respectively.From 1990 to 2000,the production of water in the Hengduan Mountain Region showed an increasing trend,and the growth area was mainly located in the western part of the Hengduan Mountains and parts of the southeast and northeast.From 2000 to 2010,the water production in the Hengduan Mountain Region decreased,and the areas involved were mainly distributed in the southern and central regions of Hengduan Mountains.From 1990 to 2010,the water yield in the Hengduan Mountain Region generally showed a decreasing trend.Among them,the decreasing regions were mainly located in the southeast and northeast of the Hengduan Mountain Region,and the growth regions were mainly distributed in the western part of the Hengduan Mountain Region.2.The spatial distribution of ecosystem water production in the Hengduan Mountain Region is uneven.It generally shows a decreasing trend from southeast to northwest.The areas with higher water production are mainly located in the central and western regions of Sichuan Province in the eastern part of the Hengduan Mountain Region and the northern regions of Yunnan Province in the southern part of the Hengduan Mountain Region.The lower water production areas are mainly distributed in the northwest of the Hengduan Mountain Region.Department of the northwestern Sichuan Province and the eastern part of the Tibet Autonomous Region.3.The water production function in the Hengduan Mountain Region is closely related to the distribution of land use types.The land use types in the Hengduan Mountain Region are mainly forest land and grassland,with high water yields in the eastern and southern regions where forest land is concentrated,and weak water production in the northern and northwestern regions where the grassland is concentrated.During the period from 1990 to 2010,the water production in the western region of the Hengduan Mountain Region increased with the increase in the area of the forest land and the reduction of the grassland area,while the water production in the northeastern Hengduan Mountain Region with the reduction of the forest land area and the increase of the grassland area decreased.4.The spatial distribution pattern of water production in the Hengduan Mountain Region is generally consistent with the precipitation,contrary to the distribution of potential evapotranspiration.There is a positive correlation between water production function and precipitation in the Hengduan Mountain Region.The average annual water production increases linearly with the annual average precipitation,while it shows a negative correlation with the potential evapotranspiration,and increases with the annual average evapotranspiration.The water production in the Hengduan Mountain Region shows a linear decrease.