Retreating Shorelines as an Emerging Threat to Adélie Penguins on Inexpressible Island

• Published in: Remote Sensing
• Main Authors: Xintong Chen, Jiquan Chen, Xiao Cheng, Lizhong Zhu, Bing Li, Xianglan Li
• Format: Article in Journal/Newspaper
• Language: English
• Published: MDPI AG 2021
• Subjects: UAV survey; penguin abundance; colony spatial extent; shoreline; elevation; Science; Q; Antarctic; The Antarctic; Inexpressible Island; Antarc*; Pygoscelis adeliae
• Online Access: https://doi.org/10.3390/rs13224718; https://doaj.org/article/bd7228acbc604f7894ac9a19f4d2afea

Long-term observation of penguin abundance and distribution may warn of changes in the Antarctic marine ecosystem and provide support for penguin conservation. We conducted an unmanned aerial vehicle (UAV) survey of the Adélie penguin ( Pygoscelis adeliae ) colony on Inexpressible Island and obtained aerial images with a resolution of 0.07 m in 2018. We estimated penguin abundance and identified the spatial extent of the penguin colony. A total of 24,497 breeding pairs were found on Inexpressible Island within a colony area of 57,507 m 2 . Based on historical images, the colony area expanded by 30,613 m 2 and abundance increased by 4063 pairs between 1983 and 2012. Between 2012 and 2018 penguin abundance further increased by 3314 pairs, although the colony area decreased by 1903 m 2 . In general, Adélie penguins bred on Inexpressible Island at an elevation <20 m, and >55% of penguins had territories within 150 m of the shoreline. This suggests that penguins prefer to breed in areas with a low elevation and close to the shoreline. We observed a retreat of the shoreline on Inexpressible Island between 1983 and 2018, especially along the northern coast, which may have played a key role in the expansion of the penguin colony on the northern coast. In sum, it appears that retreating shorelines reshaped penguin distribution on the island and may be an emerging risk factor for penguins. These results highlight the importance of remote sensing techniques for monitoring changes in the Antarctic marine ecosystem and providing reliable data for Antarctic penguin conservation.