Background As a key sediment source area in the Loess Plateau, the Beiluo River Basin has experienced severe soil erosion, which has triggered significant changes in land use and landscape patterns through ecological projects such as the Grain for Green Program. This study aims to deeply investigate the response mechanisms of land use types and landscape pattern indices to water-sediment dynamics, reveal the coupling relationship between hydrological processes and the evolution of land use and landscape patterns, clarify the impact mechanisms of ecological restoration on water-sediment interactions, and provide a scientific basis for watershed ecosystem management.

Methods This study adopted multi-source data integration and spatial analysis techniques to systematically examine the spatiotemporal evolution of land use and landscape patterns in the Beiluo River Basin over past 30 years. Data processing and spatial analysis were conducted using ArcGIS 10.8 and Fragstats, while statistical analysis was performed with Origin. Long-term observational data on runoff and sediment load from multiple hydrological stations within the basin were integrated. Pearson correlation analysis was used to quantify the relationships between land use types, landscape pattern indices, and water-sediment variables. Regression models were further established to interpret their quantitative connections, and the influence mechanisms of land use and landscape patterns on water-sediment dynamics were systematically analyzed from multi-dimensional spatial and temporal perspectives.

Results 1) Significant land use transformation occurred in the Beiluo River Basin from 1990 to 2023. The proportion of ecological land (forestland + grassland) increased to 74.94%, while cropland area decreased by 695.26 km², and forestland and grassland areas increased by 495.64 km². Most of the converted cropland was transformed into forest and grass cover. 2) Analysis of landscape pattern indices showed that the patch density of cropland and forestland increased from 0.23 to 0.32 and from 0.19 to 0.23, respectively, and the interspersion and juxtaposition index (IJI) also rose synchronously. The mean patch area of grassland expanded, and the largest patch index increased from 8.4% to 10.2%. 3) Correlation analysis demonstrated a significant positive correlation between cropland area and its landscape pattern characteristics with sediment load (P < 0.05), while grassland area and its landscape pattern features showed a significant negative correlation with sediment load (P < 0.05). However, the correlations between both cropland and grassland with runoff were not statistically significant. 4) A nonlinear response relationship was identified between runoff and sediment load (R² = 0.61), indicating that other factors have reduced the sensitivity of sediment load to runoff variations.

Conclusions Sediment load in the Beiluo River Basin is closely correlated with land use and landscape patterns. The increasing landscape dominance of forestland and grassland, along with the trend toward internal diversification and structural complexity, has enhanced vegetation-mediated soil stabilization, significantly promoting sediment reduction. The findings provide a scientific basis for land use planning, landscape optimization, and ecological conservation in the basin, and offer transferable insights for ecological restoration in the Loess Plateau and other ecologically vulnerable regions globally.