Shuitu baochi tongbao (Oct 2023)
Soil Erosion and Its Spatial Distribution Characteristics in Three-River-Source National Park
Abstract
[Objective] The Three-River-Source National Park (TRSNP) is considered to be the “water tower of China”, and is an important ecological security barrier in China. The soil erosion distribution law of TRSNP was studied to provide a basis for implementing ecological protection policy, soil and water conservation, and ecological civilization construction in TRSNP. [Methods] Based on the Chinese soil loss equation (CSLE), wind erosion model and freeze-thaw erosion intensity model, the soil erosion status and its distribution characteristics at different space and surface of TRSNP were analyzed by superposition analysis. [Results] In 2020, an area of 2.64×104 km2 suffered from soil erosion in TRSNP. Among the three sub-parks, the Yellow-River-Source Park exhibited the most extensive soil erosion, whereas the Yangtze-River-Source Park was subject to severe erosion comparatively. Soil erosion and its spatial distribution varied significantly at different elevations. Water erosion occurred mainly in the area with elevations above 4 900 m, which occupied 70% of the land area. However, 85% of the wind erosion occurred in zones with elevations less than 4 900 m. The wind erosion area with slopes between 0° and 5° accounted for 60%, which is the relatively concentrated distribution area of wind erosion. And three-quarters of water erosion areas were concentrated in regions where the slope ranged from 8° to 25°, all of which require urgent conservation measures. Grassland was the most important land cover in TRSNP, occupying about 80% of the area, with low and medium-low vegetation cover being responsible for significant soil losses. Additionally, sandy land and bare land were prone to high intensity soil erosion, which deserved special attention. [Conclusion] Two-thirds of water erosion areas were primarily located in zones where the elevation was above 4 900 m, slope gradients were between 8° and 35°, and grassland cover was below medium-low cover. Wind erosion was primarily located at elevations ranging from 4 200 m to 4 900 m, slopes were less than 5°, and grassland coverage was below medium-low cover.
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