Scenario-driven optimization of land-use/land-cover conversion pathways to improve ecosystem service performance in the Yellow River Basin

Abstract

Future land use/land cover (LULC) conversions provide a critical pathway for improving ecosystem service (ES) outcomes in large river basins, yet their contributions to comprehensive ES performance and functional synergies remain insufficiently quantified. This study projected the future dynamics of five representative ES metrics: carbon storage (CS), water yield (WY), nutrient export (NE), soil conservation (SC), and habitat quality (HQ) across multiple spatiotemporal scales in the Yellow River Basin, China. An Integrated Ecosystem Services Index (IESI) was constructed by aggregating the five normalized ES metrics to assess overall ES performance, identify priority areas for optimizing future LULC projections, compare alternative LULC conversion pathways, and evaluate socioeconomic associations with IESI, thereby providing insights for ES management. The results showed that before LULC optimization, basin-wide WY exhibited a declining trend from the historical to future periods, whereas the other ES metrics generally increased. Because NE is a negative attribute, its increase indicates weakened water-purification performance and may reflect intensified land-use pressure or agricultural activity. More diverse LULC configurations were generally accompanied by more synergies among ESs, while trade-offs mainly occurred between HQ and WY, particularly in downstream regions. IESI broadly increased, except in “spatially clustered low-performance” or “spatial mismatch” areas characterized by low-low clusters or low-high outliers of IESI and often located in upstream and midstream regions with cropland expansion. A moderate conversion of cropland and undeveloped land in LULC-optimization priority areas into a combination of grassland (12.2%–15.7% of the priority-area extent) and forest (4.3%–6.8%) was identified as the preferred conversion pathway. This pathway increased mean IESI within the priority areas by 6.2%–6.4% and basin-wide mean IESI by approximately 0.9%–1.1%. Under this LULC conversion pathway, the modelled socioeconomic-IESI relationships changed differently, with the negative association between population and IESI weakening and gross domestic product (GDP) shifting from a negative to a positive association with IESI, while significant spatial spillover effects indicated interdependence among neighboring cities. These findings warrant greater consideration of targeted LULC optimization and cross-city interactions in future basin-scale ES management.