Ecosystem Service Function Assessment Based On InVEST Model

Ecosystem is the basis of human survival and development.It can not only provide living environment and various natural resources for human society directly or indirectly,but also provide material resources and living space necessary for human life.Its service function is closely related to regional and global ecological security.Under the dual interference of climate change and human productive activities,the research on ecosystem service function has become a hot topic in landscape ecology and related research fields.The southeast coastal region of Shanghai is an important part of the"Yangtze River Delta"economic belt.Affected by the construction of Jinshan Industrial Zone,Fengxian Industrial Zone and Lingang Industrial Zone in the region,the whole ecosystem service function is facing the severe challenge of degradation.Quantitative assessment of the ecosystem service function in this region has an important guiding role in proposing the ecological structure and function regulation measures according to local conditions.In this paper,the InVEST model was used to evaluate and study the water yield,soil conservation and water purification of ecosystem services in the southeast coastal area of Shanghai in 1990,2000,2010 and 2020,and the importance of ecosystem services was graded.The priority and key protection areas in the southeast coastal areas of Shanghai are identified,which can provide a decision-making basis for the local government management departments to formulate policies on ecosystem protection and restoration.The main conclusions of this paper are as follows:(1)In terms of spatial variation pattern,the water production of ecosystem service functions in the region is"higher in the northwest,followed by in the middle and lower in the southeast".The distribution of high value and low value areas of soil conservation was scattered,and the distribution of low value areas was the most in Fengxian District of Jinshan District and Pudong New Area.The spatial distribution pattern of nitrogen and phosphorus output of water purification function had no obvious change,and the changes were all distributed in the area near the construction land and the river wet area.(2)In terms of time,the total water conservation functions of ecosystem services in the region decreased first and then increased,ranging from 1.722 billion m3to 2.016 billion m3.Total soil conservation decreased first and then increased,ranging from 1.98×10~6t to3.09×10~6t.The total nitrogen output decreased year by year,ranging from 1.33×10~6t to8.99×10~5t,and the total phosphorus output decreased year by year,ranging from 1.21×10~5t to 1.01×10~5t.In the past 30 years,the function of water yield decreased,while the function of soil conservation and water purification increased.(3)The area of water production service function reduction accounted for 64.88%,the area of soil conservation service function equalization accounted for 80.23%,the area of increase accounted for 17.04%,the area of water purification nitrogen output service decline accounted for 51.86%,the area of equalization accounted for 43.79%,and the area of water purification phosphorus output service decline accounted for 52.21%.Flat area accounted for42.5%.In the past 30 years,the water yield function decreased in most areas,the soil conservation function remained unchanged in most areas,and the water purification function increased in most areas.(4)Construction land,dry land,forest land and paddy field contributed more to the water production function in the region.Grassland,construction land,dryland and forest land contributed more to soil conservation services.Grassland,forest land and wetland contributed more to water purification function.It is necessary to increase the area of forest land and grassland,improve the vegetation coverage rate in the study area,reduce the occurrence of soil erosion,control the area and scale of construction land,and rationally arrange and plan the demand for various construction land.(5)The extremely important areas of integrated ecosystem service function are mainly distributed in the eastern and southern coastal areas of Pudong New Area,Fengxian District,Jinshan District,which is the location of the industrial zone along the southeast coast of Shanghai.The important areas are mainly distributed around the extremely important areas.Therefore,regional policy suggestions based on ecosystem service function assessment can be put forward according to importance classification,and regional ecological environment can be improved.