Exploring the historical and future spatial interaction relationship between urbanization and ecosystem services in the Yangtze River Basin, China

Diagnosing the spatial interaction between urbanization and ecosystem services (ES) is of guiding significance for regional sustainable development. The complex spatial interactions mechanism between different types of urbanization and ES during historical and future periods were rarely explored at the whole watershed scale. To fill this gap, we systematically evaluated, predicted and compared the complex spatial interaction relationship between different types of urbanization and ES in the Yangtze River Basin (YRB) during 1990–2019 and in 2050 under different Shared Socioeconomic Pathways (SSPs) and Representative Concentration Pathways (RCPs) scenarios. Results showed that economic and land urbanization in the YRB will increase sharply during 1990–2050, while the population urbanization will drop slightly during 2019–2050. More than 59% of the YRB will experience an increase in total ecosystem services (TES) in SSP1-2.6 and SSP2-4.5 scenarios during 2019–2050. The average coupling coordination degree (CCD) between urbanization and TES in the YRB ranged 0.16–0.61 during 1990–2050, with a gradual increase from severe uncoordinated to basic coordination, and experienced a transition from lagging urbanization to lagging TES. More than 64% and 38% of the YRB will achieve strong decoupling between economic and population urbanization and TES during 1990–2050, respectively, which largely occur in the upper reaches, while over 34% of the YRB belong to weak decoupling between land urbanization and TES except for SSP1-2.6, which cluster in the middle and lower reaches. Moreover, we found that SSP1-2.6 will be the most promising scenario to achieve a win-win situation between different types of urbanization and TES, while prominent conflict between them will likely emerge in SSP5-8.5 scenario. The findings can contribute to further understanding the spatial interaction relationship between urbanization and ES, and provide support for ecosystem protection and sustainable urban planning.