Abstract: Luoshan is the most important ecological barrier and water conservation land in the central arid zone of Ningxia. To explore the impact of terrain factors on the ecosystem service value (ESV) of Luoshan grassland, we used the revised ecosystem service value equivalent to estimate ESV based on remote sensing images in 2021, and analyzed its spatial distribution characteristics and terrain gradient effects. The results showed that the total ESV of Luoshan grassland was 34.18×10⁷ yuan, with desert steppe accounting for the highest proportion (50.7%). Among all the service types, the ESV of regulation service was the largest, which was 22.11×10⁷ yuan. The ESV was higher in the south region and lower in the north region, higher in the west region and lower in the east region. There was a strong spatial dependence of ESV, forming a spatial pattern of two poles gathering. The ESV of grassland showed topographic differentiation, which decreased first and then increased with the increases of elevation. The ESV increased with slope and terrain index, with the lowest ESV on the north slope and the highest ESV on the northeast slope. The results can provide scientific basis for the optimization of ecosystem pattern and grassland management in Luoshan.

Key words: grassland ecosystem, ecosystem service value, terrain gradient, spatial distribution