Biodiversity Division, National Institute for Environmental Studies, Ibaraki, 305-8506, Japan.
Planning and Research Division, National Museum of Marine Biology and Aquarium, Pingtung, 94450, Taiwan.
Mar Environ Res. 2024 Jun;198:106494. doi: 10.1016/j.marenvres.2024.106494. Epub 2024 Apr 7.
Seagrass meadows serve as critical marine habitats, offering numerous benefits to both humans and wildlife. Taiping Island, situated in the South China Sea, has been historically known for its abundant seagrass meadows. However, satellite imagery suggested there was a low density of seagrasses around Taiping Island. On the other hand, many green turtles (Chelonia mydas) were observed from the shore. To investigate this phenomenon, we conducted drone surveys of the shallow reefs and discovered a density of 902 ± 601 (mean ± SD) individual turtles per square kilometer during high tides. In addition, we conducted a cage experiment to test the hypothesis that large herbivores are impacting seagrass abundance negatively. The results indicated that the blade lengths of seagrasses in cages were significantly longer than those outside. It is likely that large herbivores such as green sea turtles are the key consumers of seagrass on the shallow reef flats of Taiping Island. Accordingly, further research and management should take into account that the increasing number of sea turtles may deplete the seagrasses and have an impact on the seagrass ecosystems.
海草床是至关重要的海洋栖息地，为人类和野生动物提供了众多益处。太平岛位于南海，历史上以其丰富的海草床而闻名。然而，卫星图像显示太平岛周围的海草密度较低。另一方面，从岸边可以观察到许多绿海龟（Chelonia mydas）。为了调查这一现象，我们对浅礁进行了无人机调查，在涨潮时发现每平方公里有 902±601 只（平均值±标准差）个体海龟。此外，我们进行了笼式实验来验证大型食草动物是否会对海草丰度产生负面影响的假设。结果表明，笼中海草的叶片长度明显长于笼外。很可能是大型食草动物，如绿海龟，是太平岛浅礁海草的主要消费者。因此，进一步的研究和管理应该考虑到越来越多的海龟可能会耗尽海草并对海草生态系统产生影响。
