Conservation of Subtropical Islands Based on Biodiversity and Regional Economy

Abstract

Land development may cause degradation of coastal ecosystems by sediment discharge through river. After the reversion of Okinawa （Ryukyu Islands） to Japan in 1972, extensive urban and agricultural development resulted in a significant increase in sediment discharge to coastal waters. The release of sediment has caused the degradation of freshwater and coastal ecosystems and biodiversity. A consideration of catchment-to-reef continua, as well as agricultural （socioeconomic） factors is necessary for establishing proper land-based management plans for the conservation of the island environment. We have set up a transdisciplinary framework to integrate biophysics and socioeconomics: 1） setting a conservation target and threshold, 2） identifying the sources and processes, and 3） examining cost-effectiveness and management priorities. The framework may be applicable to other tropical and subtropical islands with similar characteristics..