Remote sensing assessment of ecological quality of Baiyangdian wetland in response to extreme rainfall

As global warming intensifies, extreme weather has become one of the major challenges threatening the ecological environment. It remains challenging to detect and evaluate the effects of these extreme weather events on ecosystems quickly and accurately. In July 2023, extreme rainfall caused by Super Typhoon Doksuri hit North China, resulting in massive vegetation mortality in the Baiyangdian Wetland. To quickly assess the ecological loss of Baiyangdian wetland, this study obtained cloud-free remote sensing images before and after the rainfall, quantified the eco-environmental quality by RSEI (Remote Sensing-based Ecological Index) with the comparison of WBEI (Water Benefit-based Ecological Index); and then conducted spatial autocorrelation analysis to reveal the spatial heterogeneity of eco-environmental quality in the study area. The results showed that the WBEI decreased from 0.50 to 0.44 and the RSEI decreased from 0.68 to 0.64. The global Moran's Index varies from 0.681 to 0.801, demonstrating a positive correlation in the spatial distribution characteristics of eco-environmental quality. The deterioration of eco-environmental quality due to extreme rainfall was accurately captured and quantified using two remote sensing indices. Additionally, the cluster map of spatial association indicates that the High-High cluster in the sub-area Zaozhadian disappeared after the extreme rainfall, suggesting that the ecological resilience of the wetland returned from farmland was lower than that of the natural wetland in Baiyangdian. This study offers a new perspective on evaluating the impacts of extreme precipitation. By quantifying the response of eco-environmental quality, it provides scientific guidance for wetland ecological conservation efforts.