Abstract:
A study on capability of remote sensing techniques for long-term monitoring of coral reef conditions at Ko Tao, Surat Thani Province aimed to evaluate effectiveness of using LANDSAT 5 TM and LANDSAT 7 ETM+ for assessment of coral reef conditions and monitoring coral community changes at Ko Tao Island, Surat Thani Province by integrating information from satellite imagery, field survey and socio-economic study. Based on analysis of images in 1997, 1998, 2002 and 2005 at Hat Sai Ri, Ao Mae Hat, Ao Chalok Ban Kao, Ao Thian and Ko Nang Yuan using band ratios and color composition of bands 3 2 and 1 (RGB), supervised classification with maximum likelihood classifier revealed that four components of coral reef were detected, i.e., live coral, other hard substrate component except coral, soft bottom in coral reef and sandy beach with the overall accuracy ranges 60-67%. Live coral areas decreased remarkably due to mainly the severe coral bleaching phenomenon in 1998. Recovery of coral reefs in 2002 and 2005 were different among the study sites. Live coral areas at Hat Sai Ri and Ko Nang Yuan increased considerably while those at Ao Chalok Ban Kao, Ao Thian and Ao Mae Hat were no change. Socio-economic information from questionnaires and interviews of tourists, tourism companies and fishermen could be used as an indicator of coral community changes due to impacts of tourism, fishery, and coastal development activities at particular study sites.