Remote sensing-based fine-scale assessment of carbon stocks in the construction area of the Yellow River Estuary National Park

The Yellow River Estuary National Park represents an important natural ecosystem in China, enjoying rich biodiversity and unique natural landscapes. Based on 2024 GF-1 and GF-2 remote sensing images and field survey data, this study established a classification system of 28 types of terrestrial carbon sink resources, along with a carbon density reference table, for the construction area of the Yellow River Estuary National Park. Using the Integrated Valuation of Ecosystem Services and Trade-offs (InVEST) model, this study conducted a fine-scale assessment and analysis of terrestrial carbon stocks in the construction area. The results indicate that the total carbon stocks in the construction area reached 3.47×10⁶ t in 2024. Within the study area, coastal tidal flats and reed wetlands represented the two carbon sink resource types with the largest areas and the highest contributions to carbon stocks, with their areas accounting for 42.77% and 16.68% of the total and their carbon stocks 39.670% and 18.504% of the total, respectively. The carbon density in the study area exhibited a distinct spatial pattern of increasing from the coast to inland. Zones with medium carbon density covered the largest area (approximately 5.54× 10⁴ hm²), dominated by coastal tidal flats. Zones with relatively high or relatively low carbon density occupied an area of 3.31×10⁴ hm² and 1.22×10⁴ hm², respectively. Zones with high or low carbon density both occupied an area of less than 0.3×10⁴ hm². The spatial distribution patterns of carbon density and carbon stock assessment results of the construction area will contribute to more detailed assessments of carbon stocks in coastal wetland ecosystems, thereby providing a scientific reference for fine-scale conservation and management of carbon sink resources in national parks.