Thesis (M.Sc.) - Asian Institute of Technology, 2003

A thesis submitted in partial fulfillment of the requirements for the degree of Master of Science, School of Environmnet, Resources and Development

In Thailand mangrove forest has reached a critical stage, nearly 20% of mangroves found rapid decreased during 1961-1996. The main activates leaded mangrove exploitation included mangrove concession, aquaculture, and human settlement. Nowadays, Thai government has develop policy on mangrove management in order to achieve a sustainable development. Mangrove concession and all activities which destroy mangroves were banded. K.rabi is parts of Phang nga Bay, the Andaman Sea. Krabi city presented the unique characteristic which surrounded by mangrove like the lung of the city. Furthermore, it is sea lock city which has rapidly development increasing on tourism, agriculture and aquaculture sectors. The mangrove in Krabi estuary presented the ability on provide the useful value the support the local community surrounding the mangrove area, especially poorer people. The land use/ cover distribution of mangroves at K.rabi estuary were mapped using remote sensing and a Geographical Information System (GIS). Landsat Thematic Mapper (TM) and Enhanced Thematic Mapper (ETM+) which acquired 1995, 2000, and 2002 were geocorrected, processed, and analyzed using ENVI, and GIS software. Masking operation was applied into terrestrial, mangrove and water body area in order to avoid misclassification among each feature type. An unsupervised classification was performed based on spectral data from a composite image of the bands 3, 4, and 5 to each mask band. Using this output, field data together with available secondary data consisting of topography and land use maps were used to performed a maximum likelihood supervised classification. The over all accuracy of the output image was 74.14% and individual class accuracy ranged form 25% for oil palm to I 00% for mangrove. Mangrove changing was detected by overlaid the 4 land use maps on 1985, 1995, 2000 and 2002. The result obtained show that land cover change on mangrove in .Krabi estuary has occurred within the 2 past decades as a result of human activities such as aquaculture and agriculture, which has impact on the regional sustainable development. Although, mangrove in Krabi estuary were not faced high depletion problem over the past 17 years, changes within mangrove forest types were detection and its trend to decreasing in the quality of the mangrove species composition. The result from this study presented that the mangrove management zonation should not concern only quantitative, quality of the mangrove should be focused. The proper management plan has to apply into the mangrove in order to rehabilitated and maintain this mangrove being in good condition.