Ecosystem Service Function Assessment Based On Land Use Change

Land-use changes caused by urbanization,climate,and human activities have an impact on ecosystem services and,in turn,human well-being.Clarifying the response of ecosystem service functions to land use change and the correlation among service functions is an important content in the evaluation of regional ecological environment,which is of great significance to regional ecological governance and sustainable development.In this paper,Lanzhou city was selected as the study area,and five key ecosystem services,namely water yield,soil conservation,habitat quality,carbon storage and water purification,were evaluated using the InVEST model and related formulas.This paper uses spatial correlation analysis and Pearson’s method to explore the trade-off/synergy and management of ecosystem services,which lays a foundation for regional resource development,environmental planning and management,and sustainable development.Then,using the PLUS model and Markov model,by integrating the advantages of transformation analysis strategy and pattern analysis strategy,combined with the characteristics of Lanzhou city,different scenarios are set to predict the spatial distribution pattern of land use in Lanzhou city in 2030.The InVEST model was used to simulate five ecosystem service functions in the study area to verify the impact of different development strategies on the ecological environment.The main conclusions are as follows:(1)Water production service,soil conservation,habitat quality,carbon storage,and nitrogen and phosphorus pollution levels in Lanzhou decreased during the study period from2000 to 2020,while water purification capacity increased.The land use type is dominated by grassland and cultivated land,and the transfer change in the whole region is dominated by the transfer between grassland,cultivated land and unused land.Forest land had the highest carbon storage,water yield,soil conservation capacity and habitat quality,cropland had the weakest water purification capacity,water area had the strongest water purification capacity,and building land had the lowest water yield,soil conservation capacity and habitat quality.(2)From 2000 to 2020,water yield,soil conservation and habitat quality showed an increasing trend with the increase of precipitation,while carbon storage and nitrogen pollution showed an increasing trend first and then a decreasing trend with the increase of precipitation.Water yield increased with the increase of altitude,soil conservation services showed obvious fluctuations with the increase of altitude,habitat quality and carbon storage showed a trend of first decreasing,then increasing and then decreasing with the increase of altitude,nitrogen pollution showed a trend of decreasing with the increase of altitude.Water yield,soil conservation,habitat quality and carbon storage showed a decreasing trend with the increase of GDP,while nitrogen pollution showed an obvious fluctuation trend with the increase of GDP.Water yield,habitat quality,carbon storage,and nitrogen pollution showed obvious fluctuations with increasing population density,while soil conservation remained basically unchanged with increasing population density.3)The five ecosystem services all had spatial autocorrelation,and the key areas of water production services and habitat quality functions were mainly concentrated in the northwest of Yongdeng County and the high altitude areas in the southwest of Yuzhong County.The key areas provided by soil conservation service functions were mainly concentrated in most areas from southwest to northwest of Yuzhong County.The key areas of carbon storage service function are mainly concentrated in the high altitude areas of northwest and northeast Yongdeng County and a small part of northern Gaolan County.The key areas of water purification service function are mainly concentrated in the northern adjacent part of Yongdeng County and Gaolan County,and the central adjacent part of Gaolan County and Yuzhong County.(4)There was a synergistic relationship among water production services,soil conservation,habitat quality and carbon storage.There is a trade-off relationship between water purification and water production services,a synergistic relationship with habitat quality and carbon storage services,and no correlation with soil conservation services;the strength of the synergy and trade-off relationship among different services varies.(5)According to the characteristics of land use in Lanzhou and reference to relevant literature,three scenarios are set up: cultivated land protection,ecological protection and urban development.Under the cultivated land protection scenario,both cultivated land and built land increased,and the water production service and carbon storage service functions were good.Under the ecological protection scenario,the area of forest land and building land increased,and the habitat quality and water purification service function were better.Under the urban development scenario,the area of built land and water increased and the effect of the five service functions was poor.There was little difference in soil conservation services under the three scenarios.Considering the current situation of land use in Lanzhou,the cultivated land protection scenario is more in line with the current development needs of the study area in order to ensure the safety of people’s life and property and promote the sustainable and harmonious development of social economy and environment.