Data from: An expedition to Narcondam: observations of marine and terrestrial fauna including the island-endemic hornbill

Oceanic islands, known for their ecologically sensitive ecosystems and endemic species, are of high conservation significance. The volcanic island of Narcondam in the Andaman and Nicobar Islands, Indian Ocean, is a prime example and the only home of the endemic and globally endangered Narcondam Hornbill. Despite its ecological and evolutionary significance, there has been limited biological exploration and research on the island over the last century. Here, we report on a 2010 expedition to Narcondam, presenting results of our rapid survey of island invertebrates, herpetofauna, mammals and birds (especially the endemic hornbill), and marine life in adjoining waters. The survey recorded dense coral growth in the surrounding waters, and identified 17 fish, 2 sea cucumber, 8 reptile, 28 bird, and 2 mammal species and 13 spider and 8 butterfly taxa. Of these, 4 spiders, 3 butterflies and 6 birds identified to species are new records for the island. The Narcondam Hornbill was frequently encountered and we report trail-based estimates of encounter rate and density, which can serve as a baseline for future monitoring. Both despite its isolation and because of it, Narcondam has faced a number of recent and serious conservation threats, including feral goats, poaching, habitat degradation around the police camp, and proposed installations. While efforts have been made by the Government authorities to stave-off various threats, we highlight the need for further scientific research and monitoring, while according primacy to strict protection and conservation.海洋岛屿以其生态敏感的生态系统与特有物种著称，具备极高的保护价值。位于印度洋安达曼-尼科巴群岛（Andaman and Nicobar Islands）的火山岛纳尔康丹岛（Narcondam）便是典型代表，它是特有且全球濒危的纳尔康丹犀鸟（Narcondam Hornbill）的唯一原生栖息地。尽管该岛拥有重要的生态与进化研究价值，但过去一个世纪以来，针对该岛的生物勘探与研究工作始终十分有限。本研究报道了2010年对纳尔康丹岛的科考活动，展示了我们针对该岛无脊椎动物、两栖爬行动物、哺乳类与鸟类（尤其是该特有犀鸟）以及邻近海域海洋生物的快速调查结果。本次调查记录了周边海域茂密的珊瑚群落，并鉴定出17种鱼类、2种海参、8种爬行动物、28种鸟类、2种哺乳类，以及13个蜘蛛类群与8个蝴蝶类群。其中，4种蜘蛛、3种蝴蝶与6种鸟类为该岛的新分布记录。本次调查中频繁观测到纳尔康丹犀鸟，我们还报告了基于样线的观测率与种群密度估算结果，该数据可作为未来监测的基准基线。由于地处偏远且正因如此，纳尔康丹岛近期面临一系列严峻的保护威胁，包括野生山羊入侵、偷猎行为、警察营地周边的栖息地退化，以及拟议中的工程设施建设。尽管当地政府部门已采取多项举措缓解各类威胁，但我们仍强调需进一步开展科学研究与长期监测，并将严格保护与生态保育置于首要地位。