Evaluation of vulnerability of mangrove habitats using predictive habitat distribution model in Palau Islands

Abstract

 Palau Islands have rich mangrove forests, and the government plans to use them as resource of ecotourism for economic development. A method for estimating potential habitat was developed using ecological niche model at Palau Islands, in order to provide basic information for sustainable planning. Setting the area of mangrove forest in each watershed as response viable, and using Watershed area, Mountain area, Plain area, mean SPI (Stream Power Index) at mountain area, mean TWI (Topographic Wetness Index) at plain area and Bay units as explanatory variables, generalized liners model was developed.
Mean SPI at mountain area, Plain area, mean TWI at plain area and bay unit were selected as responsible environmental factors in the model. The result shows that extent of mangrove habitat is corresponded with an amount of sediment production in mountain area, capacity of sedimentation in plain area, and bay shape. Almost watersheds in Palau Islands have little potential for forming adequate habitat, and thus almost mangrove forests seem vulnerable against land alteration. Careful planning for land development is essential for the sustainable development.