Journal of Tropical Oceanography ›› 2026, Vol. 45 ›› Issue (4): 77-88.doi: 10.11978/2025235CSTR: 32234.14.2025235

• Ocean Remote Sensing • Previous Articles     Next Articles

Spatiotemporal dynamics of mangroves at the Pinglu Canal estuary based on Sentinel-2

LIANG Xixing1,2,3(), DAI Zhijun3(), LI Yan1, LI Shushi2, LI Weihua3, WANG Riming2, WU Erjiang1   

  1. 1 Guangxi Academy of Oceanography, Nanning 530022, China
    2 Guangxi Key Laboratory of Marine Environmental Disaster Processes and Ecological Protection Technology, Beibu Gulf University, Qinzhou 535011, China
    3 State Key Laboratory of Estuarine and Coastal Research, East China Normal University, Shanghai 200241, China
  • Received:2025-12-08 Revised:2025-12-26 Online:2026-07-10 Published:2026-07-31
  • Contact: DAI Zhijun. email:
  • Supported by:
    Key Special Project for International Cooperation in Science and Technology under the National Key Research and Development Program of China(2023YFE0121200); Shanghai International Science and Technology Cooperation Fund Project(23230713800); National Natural Science Foundation of China(42366008); Key Research Topics for the Guangxi Science and Technology Community in 2025(Gui Kexie〔2025〕J-004)

Abstract:

The Pinglu Canal estuary, located in the northern part of Maowei Sea, represents a typical mangrove tidal flat area subject to strong human disturbances. In this study, we employed remote sensing imagery and a GeoAI (geospatial artificial intelligence) deep learning framework to quantitatively extract the spatiotemporal dynamics of mangroves in the estuary using the U-Net model. We systematically analyzed the combined impacts of hydrodynamics, oyster aquaculture, vessel traffic, and silt-promoting wave-dissipation engineering structures on mangrove evolution. The results show that between 2016 and 2025, the overall mangrove area in the Pinglu Canal estuary declined at an average rate of 6.69 hm2·a-1. The erosion rate accelerated markedly from 2021 to 2023, with the area reduction increasing from 3.39 hm2·a-1 before 2021 to 16.30 hm2·a-1, and the shoreline retreating at a rate of -4.89 m·a-1. Subsequently, from 2023 to 2025, the rate of area loss slowed to 5.75 hm2·a-1 with shoreline retreat decreasing to -3.69 m·a-1. Erosion primarily occurred along both sides of the river channel. The study indicates that increased vessel density and the removal of oyster rafts are major drivers of mangrove degradation, whereas ecological silt-promoting and wave-dissipation structures effectively enhance shoreline stability and mitigate mangrove loss. These findings provide critical support for the coordinated development of canal navigation and mangrove ecosystem protection.

Key words: U-Net, deep learning, mangrove, Pinglu Canal estuary

CLC Number: 

  • P714