The distribution, abundance and conservation of avian biodiversity in Yellow Sea habitats in the Republic of Korea

The Yellow Sea is at the heart of the East Asian-Australasian Flyway (EAAF). It supports huge numbers of migratory shorebirds and a diverse assemblage of globally threatened species. At the same time, all three of the Yellow Sea’s main habitats (intertidal wetland, open sea and islands) are under enormous anthropogenic pressure. There has, however, been little research within the region that aims to determine distribution and to identify population trends in bird species. Improvements are also needed in methods of gathering, organising and sharing of information and data in ways that can increase their usefulness for conservation. The primary aim of this thesis is the improvement of conservation opportunities for avian biodiversity in the Republic of Korea (ROK) part of the Yellow Sea, through improving the knowledge base on birds and their habitats. This aim was fulfilled through a diverse range of research approaches. In Chapter 2, ornithological literature is reviewed, sources of bias are assessed and a method is developed through which substantial long-term declines can be identified in a third of the nation’s regularly occurring bird species. In Chapter 3, measurements are made of remaining intertidal wetland using statellite imagery and ImageJ and Arcview. We estimate that probably 75% of the ROK’s historical intertidal wetland has already been destroyed. In Chapters 4 and 5, we document declines in shorebird numbers caused by reclamation. Through survey immediately prior to and following seawall closure, we demonstrated that the majority of affected shorebirds could not relocate to adjacent wetlands following loss of a major staging site. Through a national shorebird survey, we were able to confirm that the same shorebirds were unable to relocate to other of the ROK’s internationally important wetlands. In Chapter 6, high-speed commercial ferries were used to conduct surveys of seabirds at sea, closing several information gaps on seasonal distribution and abundance, and identifying sources of bias in the count method. In Chapters 7 and 8, landbird counts were used to improve understanding of migration phenology and migration strategies. Two main migration corridors were identified, and the influence of weather systems on migration was also assessed. In Chapter 9, recommendations are made towards improving information gathering and sharing, and an index for identifying species most susceptible to decline is presented. It is intended that these methods and results will be of value and can be built on further - not only here in the ROK, but also in other regions where there are also multiple threats to biodiversity and few resources available for research and conservation.