The Coupling of Human-Water Interactions Governs Ecosystem Service Values in China's Inland River Basins: A Case Study from the Heihe River Basin

The spatio-temporal evolution of ecosystem service value (ESV) in inland watersheds is governed by the dynamic interplay of human and water systems, a process primarily mediated by land use/cover change (LUCC); investigating this process is therefore vital for informing resource allocation and policy. This study analyzed LUCC and ESV dynamics over a 33-year timeframe (1990–2023) in the Heihe River Basin, China, utilizing remote sensing imagery from four distinct periods, as well as the land use dynamic degree and equivalent factor methods. The results indicate that grassland, desert, and bare land are the dominant land use types, with the continuous expansion of construction land. Cropland and desert area fluctuated, forestland declined, and grassland and water recovered in phases, forming a gradient from downstream desertification to upstream oasis ecosystems. The total ESV increased from CNY 144.09 billion to CNY 150.44 billion, exhibiting a "declining–rising" trend. Grassland and water were the primary contributors to ESV changes, while cropland and water exhibited stable growth in the ESV. Regulating services, particularly hydrological regulation, dominated the ESV structure. Significant spatial heterogeneity existed: high-value areas clustered in upstream counties (Qilian, Sunan) and were characterized by abundant forest, grassland, and water; low-value areas occurred in downstream counties (Ejina Banner, Jinta) and were dominated by desert and bare land. Spatially, the ESV evolved through phases of "natural continuity–interference fragmentation–local recovery", driven by LUCC dynamics.