生物多样性 ›› 2021, Vol. 29 ›› Issue (7): 927-937.DOI: 10.17520/biods.2020434

• 研究报告:动物多样性 • 上一篇    下一篇

人为干扰对溪流鱼类功能多样性及其纵向梯度格局的影响

贺佳云#, 张东#, 储玲, 严云志*()   

  1. 安徽师范大学生态与环境学院, 省部共建皖江流域退化生态系统修复与重建协同创新中心, 安徽芜湖 241000
  • 收稿日期:2020-11-20 接受日期:2021-02-09 出版日期:2021-07-20 发布日期:2021-03-09
  • 通讯作者: * 严云志 E-mail: yanyunzhi@ahnu.edu.cn
  • 作者简介:# 共同第一作者
  • 基金资助:
    国家自然科学基金(31500452);国家自然科学基金(31372227);安徽省水产产业技术体系项目(皖农科)(〔2016〕84号);重要生物资源保护与利用研究安徽省省级重点实验室经费

Anthropogenic disturbances affect the functional diversity of stream fishes and its longitudinal patterns in China

Jiayun He#, Dong Zhang#, Ling Chu, Yunzhi Yan*()   

  1. School of Ecology and Environment, Anhui Normal University, and Collaborative Innocation Center of Reconstruction of Degraded Ecosystem in Wanjiang Basin Co-founded by Anhui Province and Ministry of Education, Wuhu, Anhui 241000
  • Received:2020-11-20 Accepted:2021-02-09 Online:2021-07-20 Published:2021-03-09
  • Contact: * Yunzhi Yan E-mail: yanyunzhi@ahnu.edu.cn
  • About author:# Co-first authors

摘要:

溪流鱼类多样性沿着河流纵向梯度的空间分布规律已得到大量报道, 但这些研究大多聚焦基于物种组成的分类α多样性, 而有关分类β多样性和功能多样性的纵向梯度分布规律及其对人类干扰的响应研究较少。本文以青弋江上游3条人为干扰程度不同的河源溪流为研究区域, 比较研究了人为干扰对溪流鱼类功能α和β多样性及其纵向梯度分布格局的影响。结果显示, 人类干扰改变了河源溪流鱼类功能多样性的纵向梯度格局——由线性变化变为二项式分布。此外, 我们发现, 人为干扰导致土著种被本地入侵种取代, 且较强的土地利用和水污染排放可能增大环境的不连续性, 而群落周转和嵌套变化往往取决于环境的变化。尽管功能β多样性由嵌套成分主导, 但周转成分占比相对于人为干扰较小的溪流而言明显增加。人为干扰显著改变了受干扰溪流鱼类的物种组成和功能多样性, 且功能多样性的纵向梯度格局在不同的多样性指标上存在差异。本研究强调, 在评估人为干扰下多样性的变化时, 需要从多方面考虑, 包括空间尺度和多样性指标等。

关键词: 河流连续体, 功能多样性, 物种周转, 物种嵌套, 人为干扰

Abstract

Aims: The distribution and abundance of stream fishes are influenced by historical events as well as abiotic and biotic factors. Due to the high spatial heterogeneity and temporal differentiation of stream environmental characteristics, the composition and abundance of stream fish communities vary on spatial and temporal scales. On this basis, longitudinal patterns in the diversity and distribution of stream fish along upstream-downstream gradients have garnered the widespread attention of ecologists. Previous studies relevant to the longitudinal patterns in stream fish diversity along the upstream-downstream gradient mostly focused on taxonomic α diversity, while taxonomic β diversity and functional diversity have been given less attention. Therefore, this study aimed to (1) determine the effects of anthropogenic disturbances on species composition of fishes by comparing diversity across three streams, and determine the key species contributing to the between-stream variation in fish assemblages; (2) examine the influences of anthropogenic disturbances on functional diversity, and examine if differences in functional diversity relate to α and β diversity; (3) to assess whether the between-stream variations in functional diversity show dependence on the spatial positions along the river continuum or not, and further assess the effects of anthropogenic disturbances on the longitudinal patterns in the functional α and β diversities of stream fishes.
Methods: In this study, we focused on the functional diversity of fishes, which is an effective measure for assessing the response of communities to environmental changes and predicting changes in ecosystem functioning. Using data collected in three headwater streams of the Qingyi River, China, that experience different extents of anthropogenic disturbances, we examined the effects of anthropogenic disturbances on the longitudinal patterns in the functional α and β diversities of streams fishes. We considered multiple metrics of the α diversity, including the functional richness, evenness and divergence, which measure different aspects of functional space and abundance distribution. This work also analyzed β diversity, including its turnover and nestedness components, which can provide additional insights into the processes of community changing.
Results: We found that in the less disturbed stream, functional richness increased but divergence decreased downstream, and functional β diversity decreased downstream. On the other hand, in heavily disturbed streams functional richness was higher in the upstream-midstream but lower in the downstream, and functional divergence decreased in the upstream-midstream and β diversity increased in the downstream. Anthropogenic disturbances significantly altered species compositions and functional diversity of fishes in the heavily disturbed streams, and the mode and degree to which functional diversity varied related to both the metrics of functional diversity and the spatial position along river continuum. As a result, anthropogenic disturbances caused a shift in the longitudinal patterns of functional diversity, from linear variation in less disturbed streams to unimodal distribution in heavily disturbed streams. Similarly, variations in the functional β diversity of fishes mainly occurred in the lower segments, but not in the upper segments, and were derived by the turnover component. We found anthropogenic disturbances caused the endemic species to be replaced by the native-invasive species. Heavy land use and polluting emission could increase the environmental discontinuity, leading to community turnover and nestedness changing. Although functional β diversity was dominated by the nestedness component, the proportion of the turnover component increased significantly compared with less disturbed streams.
Conclusion: Our results highlight the need for a multifaceted approach, including spatial scale and diversity metrics, in assessing the diversity changes of stream fishes under anthropogenic pressure.

Key words: river continuum, functional diversity, community turnover, community nestedness, anthropogenic disturbance