Abstract: Studies on the spatial flow of ecosystem services and their radiation area provide insights into the spatial connection between the supply area and the radiation area of ecosystem services. The spatial distribution pattern of sand-fixing service in a study area of northwest Liaoning Province was evaluated based on the Revised Wind Erosion Equation (RWEQ). The hybrid single-particle Lagrangian integrated trajectory (HYSPLIT) model was used to simulate the service space flow path for sand-fixing service, and to recognize, and calculate the sand-fixing radiative effect of the services. The results show that the total amount of sand-fixing service in northwest Liaoning Province in 2020 was 12.2 million tons, the capacity of sand-fixing was higher in the southwest part and lower in the middle and northeast parts of the study area. Sand-fixing service included 195 spatial flow paths, most of which were distributed towards northeast (83) and southeast (70), accounting for 78.46% of the total area. The radiation scope mainly involved Northeast China, North China, Yellow Sea, and Bohai Sea, covering a total area of 1 848 200 km². Sand-fixing service reduced downwind sand volume by 5 977 800 tons, benefiting 11 provinces (municipalities and autonomous regions) including Inner Mongolia Autonomous Region, Heilongjiang, Jilin, Shandong, Beijing, Hebei, and Liaoning Provinces, etc. These results constitute a robust quantitative estimation of the sand-fixing service radiation effect of the shelter forest project in northwest Liaoning Province, and could provide a decision-making basis towards strengthening the construction of ecological barriers in this area.

Key words: sand-fixing service, spatial flow, radiation effect, northwest Liaoning