Ecosystem Services and Ecosystem Assessment
LING Jiankang, GU Tianjiang, DU Kai, MAO Xufeng, XIAO Feng, YAN Jinlu, KONG Dongsheng, LIU Yinlong, YAO Naixin
Earthquakes can alter the structure of ecosystems rapidly. This study aimed to assess the impact of earthquakes on plateau ecosystems using the 2021 Maduo 7.4-magnitude earthquake as a case study. A plateau ecosystem assessment index (PEAI) was proposed based on the 3S-Integrated Valuation of Ecosystem Services and Trade-offs model (3S-InVEST) and the analytic hierarchy process (AHP). It was constructed using information on land cover, vegetation coverage, landscape pattern, habitat quality, and ecosystem service value to comprehensively evaluate the impact on plateau ecosystems. The findings revealed that: (1) After the earthquake, the overall PEAI decreased from 5.47 to 5.09, which was a decline of 6.94%. The value of ecosystem services decreased by RMB 5.5814 billion, and the degree of impact displayed a spatial gradient pattern that diminished with seismic intensity. (2) The area with intensity level X was the most affected and that with intensity level VII was the least affected, with a decline of 40.76% and 1.64% in PEAI, respectively. The spatial heterogeneity analysis revealed that land cover changes were the most drastic in Ngoring Lake, Gyaring Lake, and the river area in the north of the VII seismic intensity zone. (3) A big change in land cover was witnessed after the earthquake, whose direction was from lake wetland to sandy land, marshy wetland, and grassland, and from riverine wetland to marshy wetland and grassland. Among the various types of wetlands, marshy wetlands experienced the most significant decrease, followed by lake wetlands and riverine wetlands, with a reduction of 286.28 km2, 61.66 km2, and 30.82 km2, respectively. (4) The vegetation coverage showed structural degradation, with medium- and high-coverage areas decreasing by 6.03% and 3.16%, respectively. However, the ecosystem service value of grasslands increased against the trend, revealing their ecological resilience. The study identified land cover change, degradation of ecosystem service value, and vegetation decline as the core driving factors behind a decrease in PEAI. This assessment system provides a quantitative basis for prioritizing post-earthquake ecological restoration efforts on the plateau.