Feasibility for Rapid Assessment of Mangroves by the Application of Satellite Imagery Technique

Mangrove forests are an important wetland ecosystem that provides numerous valuable resources to the marine environment and people. Unfortunately, mangrove forests are already one of threatened environments globally mainly by human disturbance, urban development and tourism activities. The change of wetland mangroves has become an important ecological indicator of the impact on coastal areas. Understanding the factors controlling wetland structure is vital to conservation and management. The issue of mangrove change is valued by ecologists, but it is difficult to survey the area through traditional methods. In this study, multi-temporal FORMOSAT-2 and FORMOSAT-5 satellite images with a resolution of 4 metres were used to detect mangrove cover and changes. Changes of the mangroves over the study period showed that the mangroves have a slight growth trend from 2016 to 2019, and the changes are located at the edge of channel and mangrove forest. Using NDVI, the areas of mangroves were estimated at 10.5-ha., 10.6-ha. and 10.62-ha. in 2016, 2017 and 2019, respectively. The overall Kappa coefficients are between 0.86-0.94. Finally, the technique of satellite remote sensor can be a quick assessment of mangroves, which provides meaningful information for wetland management.