Abstract: Quantitative assessment of ecosystem services is a prerequisite for identifying ecological problems and formulating targeted regional environmental protection measures. There are serious ecological problems in Xiaoluan River basin in Weichang County, including low primary productivity and carbon sequestration. To solve these ecological problems, it is necessary to understand the status and spatial distribution of regional carbon storage in Xiaoluan River basin in Weichang County. Based on the InVEST model, we combined field survey data with remote sensing image interpretation to estimate carbon storage in the Xiaoluan River basin in Weichang County. The hotspot analysis method was used to identify the hotspot areas of carbon sequestration. The results showed that total carbon storage in Xiaoluan River basin in Weichang County in 2021 was 1.47×10⁷ Mg. Forest carbon storage was 5.37×10⁶ Mg, accounting for 36.64% of the total carbon storage in the basin. The spatial pattern of carbon density was characterized by high value in the southern area and low in the northern area of the basin, with a few high carbon density areas scattered in the north. The hotspots of ecosystem carbon sequestration function mainly distributed in the southern area, accounting for 28.59%, whereas the cold spots mainly located in the central and northern parts, accounting for 44.14%. The area of non-significant points was negligible. Spatial distribution of ecosystem carbon sequestration function was extremely unbalanced in the basin. Therefore, protection-oriented measures should consider hotspot areas to mitigate the impacts of human disturbance. For cold-spot areas in northern plateau areas, vegetation restoration-based measures should be implemented, such as using afforestation in areas suitable for forest to improve carbon sequestration.

Key words: carbon sequestration, aboveground carbon storage, belowground carbon storage, hotspot analysis, InVEST model.