Analysis of mangrove dynamics and its protection effect in the Guangdong-Hong Kong-Macao Coastal Area based on the Google Earth Engine platform

作者：Jiali Zeng, Bin Ai, Zhuokai Jian, Mingzhen Ye, Jun Zhao, Shaojie Sun · 发表于：Frontiers in Marine Science · 年份：2023 · DOI：10.3389/fmars.2023.1170587 · 被引用次数：12 · 研究领域：Coastal wetland ecosystem dynamics、Land Use and Ecosystem Services、Coastal and Marine Dynamics

Mangroves are rapidly disappearing in several places of the world, and mangrove dynamics are becoming important evidence of ecological restoration and protection along the coast. Mangrove populations in the Guangdong-Hong Kong-Macao Coastal Area (GCA) have experienced a substantial impact of anthropogenic pressure in the 20th century. Monitoring its spatio-temporal variation and protection effect has been regarded as an important task in coastal management. In this study, we provided the comprehensive assessment of mangrove dynamics in the GCA and typical sites from 1988 to 2020 at eight-year intervals. At this time interval, mangrove ecosystems changed significantly as a result of global warming and human impacts. The geographical distribution of mangroves was obtained by applying the Random Forest (RF) classifier on Landsat images with a 30 m spatial resolution on the Google Earth Engine (GEE) platform, based on relevant indices such as Normalized Difference Mangrove Index (NDMI), Normalized Difference Vegetation Index (NDVI), Normalized Difference Suspended Sediment Index (NDSSI), Normalized Difference Built-up Index (NDBI) and Soil Adjusted Vegetation Index (SAVI). Quantitative evaluation indicated that overall accuracy of over 88% was achieved with RF classifier for mangrove extraction. In the GCA, mangrove area was 95.4 km 2 in 1988, dropped to 71.4 km 2 in 1996, then expanded to 127.5 km 2 in 2020, with an overall dynamic rate of 1.02%. In typical sites, mangroves show...