Evaluation of the threat from sea-level rise to the mangrove ecosystems in Tieshangang Bay, southern China

Sea-level rise caused by global climate change has significant impacts on coastal zones. Mangrove ecosystems occur in the intertidal zone along tropical and subtropical coasts and are particularly sensitive to sea-level rise. We used the coastal zone of Tieshangang Bay, southern China, as a case study to evaluate the threats from sea-level rise to the mangrove ecosystems. The evaluation based on the projection of sea-level rise rates from present trend (2.9 mm/yr) and RCP4.5 scenario (0.53 m sea-level rise by 2100) of the Intergovernmental Panel on Climate Changeʹs Fifth Assessment Report, were performed for 2025, 2050 and 2100 using Sea Level Affecting Marshes Model. The results showed that the scenario using the present trend in the rate of sea-level rise would result in a 9.3%, 9.6% and 18.2% loss of mangrove habitats at the study area in 2025, 2050 and 2100, respectively. Under the IPCCʹs RCP4.5 scenario, however, the higher sea-level rise rate could result in a 11.1%, 12.2% and 25.2% loss of mangrove habitats in 2025, 2050 and 2100, respectively. The SLAMM employed was able to project the spatially explicit threats of sea-level rise on the coastal mangroves in the study area. Without proper mitigation options, the potential decrease and loss of mangrove habitats and ecosystem services in Tieshangang Bay is inevitable. Based on the results of this study, mitigation measures should be considered for securing the mangrove ecosystems, including managing sedimentation and controlling reclamation and rehabilitation.