生物多样性 ›› 2017, Vol. 25 ›› Issue (8): 830-839.DOI: 10.17520/biods.2017108

• 研究报告: 动物多样性 • 上一篇    下一篇

低头坝驱动山区溪流局域栖息地和鱼类群落的同质化

卜倩婷, 李献, 朱仁, 储玲, 严云志*()   

  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 发布日期:2017-08-31
  • 通讯作者: 严云志
  • 作者简介:# 共同第一作者 Co-first authors
  • 基金资助:
    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 Published:2017-08-31
  • Contact: Yan Yunzhi

摘要:

确定溪流鱼类多样性对环境变化和人类干扰的响应, 可为溪流生态系统及鱼类多样性的保护和管理提供科学基础。本文基于对安徽省青弋江流域上游的4条一级河源溪流中39个低头坝、78个调查样点(针对每个低头坝所处河段, 分别设置坝上蓄水区(impounding area)和坝下非蓄水区(free-flowing area)各1个调查样点)的调查数据, 研究了低头坝对局域栖息地和鱼类群落同质化的驱动作用。共采集鱼类27种, 隶属5目10科, 其中蓄水区和非蓄水区的物种分别为23种和27种。主坐标分析和主坐标典范分析结果显示, 蓄水区与非蓄水区间的局域栖息地存在显著差异, 同非蓄水区相比, 蓄水区的底质粗糙度和异质性较小但水深和水宽较大; 置换多元分散分析结果显示, 蓄水区局域栖息地特征的空间变异显著低于非蓄水区, 呈现出明显的同质化现象。以非蓄水区为对照, 蓄水区鱼类群落的相似性在研究的4条溪流、2个不同季度呈现出相似的变化趋势, 即: 一些鱼类群落间的相似性上升但另外一些群落间的相似性下降, 且其相似性变化大小(ΔCSJ)与初始相似性显著负相关; 当初始相似性较低时, ΔCSJ > 0; 当初始相似性较高时, ΔCSJ < 0。本研究表明, 低头坝导致了坝上蓄水区局域栖息地特征空间变异的下降, 呈现出明显的栖息地同质化; 但蓄水区鱼类群落同时存在同质化和异质化2个过程, 群落间初始相似性大小决定了其同质化或异质化: 初始相似性较低呈同质化、较高则异质化。

关键词: 栖息地同质化, 生物同质化/异质化, 溪流鱼类, 低头坝

Abstract:

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.

Key words: habitat homogenization, biotic homogenization/heterogeneity, stream fishes, low-head dam