Longitudinal patterns of fish assemblages in relation to environmental factors in the Anning River, China

• Published in: Ecological indicators Vol. 146; p. 109864
• Main Authors: Ma, Baoshan, Chu, Zhipeng, Zhou, Ruihang, Xu, Bin, Wei, Kaijin, Li, Bing, Zhao, Tianyi
• Format: Journal Article
• Language: English
• Published: Elsevier Ltd 01.02.2023; Elsevier
• Subjects: Discontinuities; Fish diversity; Fish zonation; Hydropower station; Plateau species; Hydropower station; Fish zonation; Fish diversity; Discontinuities; Plateau species
• ISSN: 1470-160X; 1872-7034
• DOI: 10.1016/j.ecolind.2023.109864

•Two site-groups were classified, corresponding to upstream-tributaries and mid-downstream.•Altitude and the proportion of substrate composition were major environmental variables influencing the spatial patterns of fish assemblages.•Compared with natural riverine conditions, reservoirs and dams seemed to affect fish communities to a small extent.•To protect the fish diversity of Anning River, construction of hydropower stations and sand extraction activities should be managed. In order to explore the spatial layout of fish assemblages and their related environmental factors, a survey of species composition was conducted in the Anning River. From 2018 to 2021, 28 sites at 987–2,077 m in altitude were surveyed, gathering 64 species in total, of which 60 were native and 4 were exotic. Fifteen of the species sampled were indigenous to the upper Yangtze River, and two were classified as critically endangered or endangered. Fish communities displayed significant upstream-to-downstream variation. There are two site-groups, one covering upstream and tributaries and the other covering midstream and downstream. The upstream-tributary fish assemblages had a dominance of Nemacheilidae and Schizothoracinae, which are plateau species with habitat preferences for boulders and fast-flowing water. Conversely, the mid-downstream fish assemblages had a dominance of Gobioninae, Cyprininae, Bagridae and Siluridae, which are common river species that prefer slow-flowing water. The spatial patterns of these fish communities were chiefly affected by altitude and substratum composition. The fish assemblage pattern was consistent with the zonation concept because the fish communities changed abruptly and clearly along the upstream–downstream axis. The findings of this study offer a crucial research foundation for comprehending the fish assemblages of mountainous rivers, which will be conducive to biodiversity management and habitat preservation of aquatic species.