Introduction -- Research contents and methodology -- Study area and sample collection -- Chronology -- Geochemical evidence for the development of coral island ecosystem in the Xisha archipelago of the South China Sea -- A 2200-year record of seabird population on Ganquan Island, South China Sea.- Isotopic evidence for seabird diet changes over the past  2000 years in the Xisha Islands.- Evidence of human activities from the ornithogenic sediments of the Xisha Islands -- A preliminary study of ancient DNA in guano subfossils from the Xisha Islands -- Conclusions.

This study describes the fundamentals of assessing the vulnerability of coral islands, as well as environmental management and resource exploitation. Using seabird subfossils, such as bones, guano, eggshells etc., which have been well preserved on the Xisha Islands in the South China Sea, the author identifies the influences of climate change and human activity on seabird populations and diets. Understanding the past is of great importance for predicting the future, and seabird subfossils provide valuable information, which can be used to study changes in seabird ecology, paleoceanography and palaeoclimate. Furthermore, this study proposes examining the biogeochemical cycling of some elements present in the geosphere, hydrosphere, biosphere and atmosphere. Dr. Liqiang Xu works at the Hefei University of Technology, China.