Spatio-temporal variation and influencing factors of ecol-environment quality in Jiuzhaigou County, Sichuan, China under seismic disturbance

Abstract

Accurately monitoring and evaluating changes in ecological environment quality under earthquake disturbances is of great significance for the restoration and protection of regional ecological environment. In view of the "8·8" earthquake in Jiuzhaigou County in 2017, we used high-precision remote sensing image to analyze the vege-tation damage caused by the earthquake, and calculated remote sensing ecological index (RSEI) for the pre-earthquake period, post-earthquake period and 3-year recovery period based on GEE platform to analyze the spatio-temporal variation of ecological environment in Jiuzhaigou County, Sichuan Province. Then, we used geodetector to reveal the influencing factors of spatio-temporal variations in ecological restoration. The results showed that the fractional vegetation cover of Jiuzhaigou County decreased from 0.71 before the earthquake to 0.69 after the earthquake. The area of higher coverage zone decreased by 310.78 km², while the area of others increased. The mean RESI decreased from 0.50 in the pre-earthquake period to 0.42 in the post-earthquake period, and increased to 0.50 after the 3-year recovery period. The ecological environment quality in the three period was mainly at the good and ave-rage levels, and it was distributed in the central and southern mountains and the eastern river valley. Annual precipitation, elevation, wet and greenness were the main factors controlling ecological quality restoration in Jiuzhaigou County, and the increases in the interaction among these factors would affect the spatial variations of regional ecological environment quality restoration.

Keywords: Jiuzhaigou County; earthquake; ecological environment quality; geodetector; remote sensing ecological index.