467 / 2024-09-17 17:28:58

Effect of beach erosion and typhoon on green turtle nesting grounds and implications for conservation management at Xisha Islands, South China Sea

Beach erosion; Green turtle; Hatching success; Island morphology changes; Nesting ground

Sea turtles are ideal flagship and umbrella species for marine biodiversity conservation. The quality of nesting grounds is crucial for the successful reproduction of sea turtles, determining whether they can successfully nest and hatch. Xisha Islands represent the largest remaining nesting grounds for green turtles in China, but face numerous threats and lack management guidelines for nesting ground restoration. From 2019 to 2022, this study continuously monitored the beach changes and coastal erosion in North Island of Xisha Islands. Results show that from 2020 to 2022, the beach area of North Island decreased annually by 11,840 m². The proportion of suitable nesting sand types (including coarse and medium sands) also decreased annually. The peak nesting period of green turtles on North Island coincides with the high occurrence of typhoons in South China Sea, causing tidal surges that inundate green turtle nests and result in an average nest loss rate of 35.25%. Based on the above threats, it is recommended to promptly initiate habitat restoration in severely eroded areas of green turtle nesting grounds, to prevent further declines in nesting area and quality, and to implement measures such as nest relocation to enhance green turtle reproductive success.