Abstract: Constructing a scientifically sound ecological compensation mechanism is a crucial approach to harmonize regional ecological conservation with socio-economic development, which has significant implications for the sustainable use of ecosystem services. Based on multi-source remote sensing data, we quantified the supply and demand of ecosystem carbon sequestration service in Fujian Province. With the supply-demand ratio, hot/cold spot analysis, and breakpoint-field strength models, we examined the spatial flow features (direction, rate, and flux) of carbon sequestration services in Fujian from 2000 to 2020, and further quantified ecological compensation with considerations of payment capacity and willingness to pay. The results showed that both the supply and demand of ecosystem carbon sequestration in Fujian Province increased significantly between 2000 and 2020. The supply showed a northwest high and southeast low distribution, while the spatial distribution of demand exhibited the opposite pattern. There was a mismatch between dominant supply and demand for ecosystem carbon sequestration services in Fujian Province, which was worsening over time. Coastal areas typically exhibited a supply-demand deficit with low supply-high demand and high supply-high demand, while other regions mostly showed a supply-demand surplus with high supply-low demand. In 2020, the ratio of counties between the supply region and the demand region for ecosystem carbon sequestration was 9:32, showing a spatial pattern of west supply and east input. The total carbon outflow from the supply region was 4264107 t, with the largest outflow from Zhangping City and the largest inflow to Changtai District. The payment to the compensated areas should been 182 million yuan, but the actual expenditure was 91.16 million yuan. Changtai District had the highest actual expenditure, while Zhangping City had the highest actual income.

Key words: ecosystem carbon sequestration service, supply-demand matching, ecosystem service flow, ecological compensation, Fujian Province