• 研究报告: 动物多样性 •

### 低头坝驱动山区溪流局域栖息地和鱼类群落的同质化

1. 安徽师范大学生命科学学院, 安徽省高校生物环境与生态安全省级重点实验室, 安徽芜湖 241000
• 收稿日期:2017-03-31 接受日期:2017-04-15 出版日期:2017-08-20
• 通讯作者: 严云志 E-mail:yanyunzhi7677@126.com
• 作者简介:# 共同第一作者 Co-first authors
• 基金项目:
国家自然科学基金(31372227, 31500452)、安徽省水产产业技术体系项目(皖农科[2016]84号)和生物环境与生态安全安徽省高校省级重点实验室经费

### Low-head dams driving the homogenization of local habitat and fish assemblages in upland streams of the Qingyi River

Qianting Bu, Xian Li, Ren Zhu, Ling Chu, Yunzhi Yan*()

1. Provincial Key Laboratory of Biotic Environmental and Ecological Safety, College of Life Sciences, Anhui Normal University, Wuhu, Anhui 241000
• Received:2017-03-31 Accepted:2017-04-15 Online:2017-08-20
• Contact: Yan Yunzhi E-mail:yanyunzhi7677@126.com

Identifying how fish assemblages in upland streams respond to environmental changes and anthropogenic activities is the basis for the conservation and management of upland stream systems and fish diversity. Based on data collected from 78 sampling sites (including 39 impounding areas and 39 free-flowing segments, respectively) associated with 39 low-head dams in four 1st-order streams of the Qingyi basin in Anhui Province, we investigated the effect of low-head dam on the habitat homogenization and the biotic homogenization of fish assemblages in upland streams. A total of 27 species representing 10 families and 5 orders were collected, among which 23 and 27 species were collected from the impounding and free-flowing areas, respectively. Principal coordinate analysis (PCoA) and canonical analysis of principal coordinates (CAP) results showed that the local habitat differed significantly between impounding and free-flowing areas, the former characterized by relatively low substrate coarseness and heterogeneity and the latter showing shallower water depth and width. Permutational analysis of multivariate dispersions (PERMDISP) result indicated that the heterogeneity in spatial variability of the local habitat was significantly lower in the impounding areas than the free-flowing areas, suggesting habitat homogeneity in the impoundments of low-head dams. The variations in the coefficient of similarity of fish assemblages in the impoundments relative to that found in the free-flowing segments were consistent across the four study streams and the two sampling seasons. Compared with that in the free-flowing segments, the between-assemblage similarities for fishes in the impoundments either increased or decreased, of which ΔCSJ was negatively related to the initial similarity of fish assemblages. ΔCSJ was positive when the initial similarity was lower than 50%, while ΔCSJ was negative when the initial similarity was more than 50%. Our results suggest that low-head dams may decrease the spatial variability in local habitat within the impounding areas of dams and result in the homogeneity of the local habitat. However, the variations in fish assemblages within these impoundments include two ecological processes, i.e., biotic homogeneity and heterogeneity. The biotic homogeneity/heterogeneity depends on the size of the initial similarity between different assemblages. The assemblages showing relatively low initial similarity will be homogenized and those of high initial similarity will be heterogenized.