Spatio-Temporal Changes of Mangrove-Covered Tidal Flats over 35 Years Using Satellite Remote Sensing Imageries: A Case Study of Beibu Gulf, China

Tidal flats provide ecosystem services to billions of people worldwide; however, their changing status is largely unknown. Several challenges in the fine extraction tidal using remote sensing techniques, including tide-level and water-edge line changes, exist at present, especially regarding spatial temporal distribution mangroves. This study proposed a method combination threshold segmentation tidal-level correction, considering influence mangrove changes. We extracted Beibu Gulf, Southwest China, from 1987 2021 time-series Landsat Sentinel-2 images, further analyzed dynamic variation characteristics total flats, each coastal segment, range erosion silting. To quantitatively investigate interaction between mangroves, this established regression model based on multi-temporal data. The results indicated that overall accuracy flat was 93.9%, kappa coefficient 0.82. area Gulf decreased by 130 km2 2021, with an average annual change −3.7 km2/a. In addition, negative correlation Shankou, Maowei Sea, Pearl Bay observed, coefficients −0.28, −0.30 −0.64, respectively. These demonstrate provides good environment expansion space for rapid growth can references flats’ resource conservation, ecological health assessment, vegetation changes wetlands China other countries Southeast Asia.