A GIS-Based Assessment of Threats to the Natural Environment on Koh Tao, Thailand

Abstract

               The objective of this study was to provide an overview of the issues affecting the natural resources on Koh Tao, Thailand, so a management plan could be developed. Remote sensed data was combined with data from a questionnaire to create a model that assesses the condition of the reefs and threats to the reefs. Remote sensed data were acquired from 4 y (1975, 1994, 2001 and 2005) to assess changes in land usage and to determine the location of the reefs. With a geographical information system (GIS) different models were created based on the available data.

                 The results showed that areas on the northeast side of the island were in better condition than other areas. In recent decades, almost 50% of the rainforests have been lost, with soil erosion and subsequently sedimentation on the reefs as a consequence. The enormous reef recreation industry on the island has also caused stress to the reefs. While it was expected that the divers from the large number of diving schools would cause damage to the coral, commercially organized snorkel trips appeared to be more destructive. Most reef areas that were stressed suffered from sedimentation and physical damage caused by snorkeling and diving.