Green sea turtle (Chelonia mydas) is the only sea turtle species breeding in China, and the Qilianyu of Xisha Islands are the largest remaining nesting grounds of green sea turtles in Chinese waters. Nesting site selection is particularly important for the survival of eggs, and understanding the micro-habitat characteristics of green sea turtle nesting sites is crucial for delineating priority conservation areas for nesting grounds. In this study, we examined several micro-habitat ecological factors of the usage and control quadrats, as well as successful and aborted nests, through differential comparisons, principal component and generalized linear model analysis. There were significant differences in micro-habitat ecological factors such as temperature, humidity, and particle size distribution (0.250-1 mm) between the usage and control quadrats. The nests of green sea turtle were concentrated at a distance of 20.1-30 m from the high tide line, with a preferred distance from vegetation of 0-0.5 m. The vegetation cover of successful nests was concentrated in the range of 0-25%, and the preferred sand types for successful nests were coarse sand (0.425-1 mm) and medium sand (0.250-0.425 mm). The key micro-habitat factors affecting the success of nesting were found to be sand characteristics such as humidity, bulk density, and ratio of particle size. Therefore, green sea turtles in the Xisha Islands exhibit preferences for micro-habitat ecological factors in nest site selection, and the ecological factors of nesting grounds can affect the hatching success rate of green sea turtles. It is recommended to continuously monitor the characteristics and changes in green sea turtle nest site selection and take measures to provide high-quality nesting and hatching environments for sea turtles.
 

Green sea turtle; Nest site selection; Nesting grounds; Micro-habitat; Hatching success