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.