Urbanization-Induced Changes in Water-Related Ecosystem Service Values in the Yangtze River Basin, China: A GIS-Based Service-Level Assessment, 2000–2022

Sustained urbanization in the Yangtze River Basin has restructured land cover across China's longest river system and altered the capacity of that system to deliver water-related ecosystem services. Basin-scale monetary valuations published to date aggregate all eleven ecosystem services into a single figure and are therefore unable to determine whether the services that regulate and supply water follow the composite trend. This study addresses that gap. Landsat imagery for 2000, 2011, and 2022 was classified into six land use and land cover categories. An equivalent factor valuation calibrated to regional grain productivity resolved all eleven services individually for each category, and hydrological regulation and water supply were then analyzed separately from the aggregate. A human activity intensity index and geographical detector model were used to attribute the observed changes to candidate driving factors. Built-up land expanded by 77.84%, from 318.56 to 566.41 ×10⁴ hm², while cropland, forest, grassland, water, and bare land all contracted. Total ecosystem service value fell from 416,500.38 to 428,011.13 ×10⁸ RMB over the 2000 to 2011 sub-period before stabilising, with the natural and agricultural land subtotal recording a net decline of 1.87% across the full 2000 to 2022 period. That aggregate obscures the water signal. Water-related service value on natural and agricultural land declined by 2.01%, while the basin-wide total for those two services appeared to increase because the coefficient assigned to built-up land credited urban expansion with water-related value that exceeded its hydrological contribution. Forest recorded the highest sensitivity coefficient at 0.7214 and remains the dominant reservoir of water-related value. Human activity intensity explained 87.60% of the spatial variance in ecosystem service value, far exceeding the explanatory power of per capita GDP, population density, or vegetation cover considered independently. Upper-reach forest protection and middle-reach farmland conservation are therefore the priority instruments for maintaining water-related service capacity in the face of continued delta-ward urbanization.

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