Differentiated Climate Drivers of Carbon and Water Use Efficiencies Across Land Use Types in the Yellow River Basin, China

Given the crucial role of land use in shaping coupled water–carbon processes in ecosystems, it is essential to assess carbon use efficiency (CUE) and water use efficiency (WUE) across different land use types. This study established an analytical framework incorporating trend analysis, partial correlation, and relative contribution methods to evaluate how WUE and CUE in the Yellow River Basin (YRB) responded to key climatic variables between 2001 and 2023. It also identified the dominant climatic drivers across different land use types during 2001–2022. The principal findings were as follows: (1) from 2001 to 2023, the mean WUE and CUE were 0.73 g C m−2 mm−1 and 0.60, respectively. (2) Wetlands and croplands had higher WUE, while grasslands and shrublands showed higher CUE. (3) MAT was negatively correlated with WUE and CUE across 89% and 74% of the YRB, respectively, while MAP and SR showed spatially variable effects. (4) MAT was the dominant factor driving WUE variation across all land use types (accounting for approximately 40%). Except for shrublands, CUE was mainly influenced by MAP. These results highlight differentiated climate impacts across land use types, providing important insights for ecosystem restoration and spatial governance.