Abstract: The Luan River Basin serves as a vital green ecological barrier in the Beijing-Tianjin-Hebei region, and land use changes affect carbon storage capacity in the basin. Quantitative analysis of the spatial and temporal variations of carbon stocks and conducting dynamic simulation based on the future scenarios are of great significance to maintaining the ecosystem stability and sustainable development. The InVEST and PLUS models were used to assess the land use changes and their impacts on the spatial and temporal variations of carbon stocks in the Luan River Basin under three development scenarios from 2000 to 2020 and 2030. The Moran’s I index was calculated to investigate the spatial aggregation of carbon stocks at the grid scale. The relationship between the land use intensity and carbon stock change was analyzed. The results showed that: (1) grassland and construction land continuously expanded from 2000 to 2020, while arable land, forest land, water bodies, and unused land displayed a decreasing trend. The carbon storage in the Luan River Basin was 38305.9×10⁴, 38074.1×10⁴, and 37984.3×10⁴ t in 2000, 2010, and 2020, respectively. The main reason for the decrease was the conversion from high-density-carbon land use types to low-density-carbon ones. Carbon storage exhibited a “low-high-medium” distribution pattern from northwest to southeast. Under the scenarios of natural development, urban development, and ecological conservation, carbon storage was estimated to be 37895.9×10⁴, 37853.1×10⁴, and 38065.8×10⁴ t, respectively. The ecological conservation scenario was beneficial for enhancing the carbon storage capacity. (2) The spatial distribution of carbon storage showed positive autocorrelation and strong clustering characteristics. Highvalue clusters were mainly located in the middle and lower reaches of the basin, while low-value clusters were distributed in the upper reaches. (3) The proportion of coordination types between land use intensity and carbon storage change was as follows: transition type > coordinated development type > imbalance type. The areas with barely coordinated land use and carbon storage change had the highest proportion in all time periods. Our results can provide scientific references for the optimization of land use patterns and the enhancement of ecosystem carbon sink capacity at the watershed scale.

Key words: land use change, carbon stock, Luan River Basin, PLUS model, InVEST model, future scenario simulation