MANGROVE FOREST DISTRIBUTION AND DYAMICS OF THE CA MAU PENINSULA, MEKONG DELTA USING LANDSAT IMAGERY

摘要

In the past three decades, land covers have changed in the Mekong delta, Vietnam with difficulty for stable and sustainable management. Therein, mangrove has significantly changed during that period due to shrimp culture development rapidly. Therefore, monitoring a spatio-temporal distribution and changes of mangrove is critical for natural resource management. To contribute better management for mangrove and coastlines in the area, the research objectives were: to map the current extent of mangrove in Camau peninsula from 1989 to 2015, and to identify change of mangrove. The data were processed through four main steps: (1) data pre-processing including atmospheric correction, image normalization, and cloud removal, (2) image classification using supervised classification approach, (3) accuracy assessment, and (4) change detection analysis. Validation was made by comparing the classification result with the ground reference data, which yielded agreement with overall accuracy 77.4% and Kappa coefficient of 0.68. The results showed that mangrove has decreased by half (236.07 km2) from 1989 to 1998 due to shrimp culture. At the same time, the area of mix shrimp and mangrove increased by 386.69 km2 (about 88%). However, mangrove and mix mangrove, and shrimp areas have been raised by twice for mangrove and about 11% for mix mangrove and shrimp, respectively, in the second period from 1998 to 2015. These changes of mangrove were affected by two activities: deforestation, and replanting or newly formed. The development of aquaculture has been increasing quite rapidly and in an unplanned way. It also caused environmental and natural resources problem as well as socio-economic aspects. Research results for mangrove mapping and change detection in the study area are capable of providing quantitative information of long-term land-use change for coastal management in the Mekong delta.