Connectivity of Hills, Humans and Oceans Unit, Kyoto University, Kyoto, Japan.
Faculty of Fisheries Sciences, Hokkaido University, Hakodate, Hokkaido, Japan.
PLoS One. 2020 Oct 6;15(10):e0231127. doi: 10.1371/journal.pone.0231127. eCollection 2020.
Biodiversity is an important parameter for the evaluation of the extant environmental conditions. Here, we used environmental DNA (eDNA) metabarcoding to investigate fish biodiversity in five different estuaries in Japan. Water samples for eDNA were collected from river mouths and adjacent coastal areas of two estuaries with high degrees of development (the Tama and Miya Rivers) and three estuaries with relatively low degrees of development (the Aka, Takatsu, and Sendai Rivers). A total of 182 fish species across 67 families were detected. Among them, 11 species occurred in all the rivers studied. Rare fishes including endangered species were successfully detected in rich natural rivers. Biodiversity was the highest in the Sendai River and lowest in the Tama River, reflecting the degree of human development along each river. Even though nutrient concentration was low in both the Aka and Sendai Rivers, the latter exhibited greater diversity, including many tropical or subtropical species, owing to its more southern location. Species composition detected by eDNA varied among rivers, reflecting the distribution and migration of fishes. Our results are in accordance with the ecology of each fish species and environmental conditions of each river.
生物多样性是评估现存环境条件的一个重要参数。在这里，我们使用环境 DNA（eDNA）宏条形码技术来调查日本五个不同河口的鱼类生物多样性。从两个高度发达的河口（多摩川和宫川）和三个相对不发达的河口（赤川、高津川和仙台川）的河口和沿海地区采集 eDNA 水样。共检测到 67 科 182 种鱼类。其中，11 种鱼类出现在所有研究的河流中。在富有的自然河流中成功检测到了濒危物种等稀有鱼类。仙台河的生物多样性最高，多摩河的生物多样性最低，反映了每条河沿的人类发展程度。尽管赤川和仙台河的营养浓度都较低，但由于后者的地理位置更靠南，其多样性更大，包括许多热带或亚热带物种。eDNA 检测到的物种组成在不同的河流之间存在差异，反映了鱼类的分布和迁移。我们的结果与每个鱼类物种的生态学和每个河流的环境条件相符。
