Divergent impacts of urbanization on ecosystem services in urban versus non-urban agglomerations of the Yangtze River Basin, China during 1990–2050

Exploring the long-term spatial heterogeneity effect of urbanization on ecosystem services (ES) in large river basin is critical for differentiated sustainable governance. However, few studies have systematically compared the divergent impacts between urban and non-urban agglomerations across historical and future periods. Assess and predict the spatiotemporal evolutions of ESs (water yield, soil conservation, carbon storage, and habitat quality) and urbanization (economic, population and land urbanization) in the Yangtze River Basin (YRB) of China during 1990–2050, comparing the impacts of urbanization on ES in urban agglomeration, non-urban agglomeration and the whole YRB. ESs were measured by InVEST model, Revised universal soil loss equation and Water balance Equation. Geographical Detectors and nonlinear regression were employed to reveal the impact of urbanization on ES. (1) Total ecosystem services (TES) in 61.83% and 59.28% area of the YRB will increase in SSP1-2.6 (sustainable development) and SSP2-4.5 (moderate development) during 2019–2050, while reduction in TES account for 47.20% in SSP5-8.5 (fossil-fueled development). (2) Logarithmic or exponential functions mostly illustrate the relationships between TES and urbanization. The impact of land urbanization on ESs was greatest in non-urban agglomeration, while population urbanization had greater impact in urban agglomeration and the whole basin. (3) The interactive effects of land and other urbanization on ESs exceed those between economic and population urbanization. (4) SSP1-2.6 aligns better with large cities featuring advanced ecological governance, SSP2-4.5 suits small and medium-sized cities balancing emission reduction with socioeconomic priorities. Negative influences of urbanization on TES will decrease under SSP1-2.6 and SSP2-4.5 scenario in 2050. Differentiated scenario adaptation strategies need to be designed based on city size and ecological endowment. The findings offer insights for informing sustainable urban ecological protection in the YRB and similar large river basins globally.