Evolution of ecosystem service value in rural regions based on geographical scope of entities: A case study of Nanjing, China

Rural areas have very important ecological service functions. This study investigated the evolution of ecosystem services value (ESV) in rural regions based on the physical geographical scope of rural areas. The replacement value method, shadow price method, precipitation stock method, quantitative measurement by Remote Sensing and Carnegie-Ames-Stanford approach (CASA) model calculations were used to analyze the evolution of ESV (Nutrient cycling, Maintaining atmospheric balance, Organic matter production, Water conservation) in Nanjing's rural regions between 1985 and 2016. The results show that: (1) From 1985 to 2000, all types of rural ESV showed a trend of decline. From 2000 to 2016, all ESV except for water conservation continued to decrease. (2) In the first stage, areas with large losses in rural ESV were mainly concentrated in southerly, southwesterly, and southeasterly directions. In the second stage, only the northerly and northwesterly directions had increased, whereas all other directions had decreased by varying extents. (3) During the stage of township industrialization, ESV were significantly affected by land use changes in rural areas. During the stage of rapid urbanization, urban expansion had a greater impact on rural ESV. Further studies reveal that rural ecosystem service changes are also influenced by deeper factors, with land use change and excessive nutrient loading as direct drivers significantly affecting rural ecosystem service change processes, and economic development and population growth as indirect drivers changing the spatial distribution of ecosystem services by affecting land use patterns and ecosystem quality. In conclusion, we combined geographical spatial analysis with ecological thinking to provide support for the maintenance of rural ESV and sustainable development.