Ecosystem Services Evaluation Based On In VEST Model

With the increasing pressure from population and expansion of demand, excessive human exploitation of ecosystem resources and ecological damage to the environment have led to irreversible ecological impacts, which caused severe degradation of ecosystem services furthermore. In order to avoid further destruction, we must strengthen the reasonable planning and management of ecosystem services. Quantitative assessment of ecosystem services is a prerequisite for the ecological environment management decisions, which can let administrators have an intuitive understanding of the ecosystem services. At the same time the evaluation results can be applied to a wider variety of management decisions, the overall coordinated economic development and ecological construction.Taking Yanqing district of Beijing as study area, where population density, land shortage and ecosystem services change are all at a high level, this paper analyzed the land use and land cover change of Yanqing District in 2004,2009 and 2014 based on remote sensing data, and used InVEST quantitative models to assess the amount of carbon sequestration, water yield and soil conservation, described ecosystem services in spatial distribution and temporal changes. Then according to each evaluation result, we divided study area into three different grades, which are area with high ecosystem services level, medium and low respectively. Meanwhile, we analyzed the impact of land use changes on ecosystem services by correlation and regression methods. The results of the study shows that:During 2004～2014, the land-use and land-cover change of Yanqing District was quite significant. The general trend during study period was that forest and urban land increased by 3.43%,8.69% respectively, while farmland and bare land decreased by 9.9%,16.79% accordingly, and the conversion of different land use types was fairly frequently. The land use change had affected the pattern of ecosystem services and caused a corresponding change. During the study period, the increasing of forest along with the decreasing of farmland and bare land cause that the carbon sequestration and soil conservation had increased by 55.06×104,700×104. But forest expansion caused more evapotranspiration, which reduced water yield in Yanqing by 1.286×108 mm.In terms of spatial distribution, carbon sequestration, soil conservation and water yield in Yanqing District have a high consistency. Areas with high service function value were mainly distributed in most forest land of Yanqing, while areas with low value were mainly concentrated in the center of the basin in Southwest of Yanqing where urban land was the representative type.Land-use and Land-cover Change closely connected with the ecosystem services changes and is the one of direct driving force causing ecosystem services changes. Forest is the main carrier of ecosystem services in Yanqing and has a profound impact on carbon sequestration, water yield and soil conservation.InVEST model, is a scientific and feasible method for ecosystem services evaluation of the large-scale area. In the process of practical application, we should strengthen the parameter calibration and improve data quality in order to ensure the accuracy of analysis results.