Area of Sinan Dadohae Biosphere Reserve (SDBR) is composed of very unique ecosystems and biological spectrum spatially networking with terrestrial, tidal flat and marine landscapes. According to the principles of UNESCO BR, SDBR will accomplish the statutory framework for conservation, development and logistic support in biosphere reserve. The core zone of SDBR includes three islands and four natural monuments, which designated as Dadohae Marine National Park. This area is composed of terrestrial ecosystem and marine ecosystem, and huge tidal-flat ecosystem is connecting two ecosystems. Core zone of SDBR show dynamic mosaic landscapes to which various biological species are spatially adapted in the habitats. Therefore, it is significantly meaningful that this area is important area for world biological conservation. Warm-temperate evergreen broad-leaved trees, conifers and rare plants designated as natural monuments are grown in the terrestrial area of the core zone. As well as geographical isolation of biological species, this area shows the climatic characteristics in warm and humid ocean. The temperate broad-leaved forest ecosystem and evergreen broad-leaved forest ecosystem are mixed in this area. As one of eco-region, the area is academically very significant, and it is important role for main axis of national island-coast ecological network in Korean Peninsula.