Department of Aquatic Ecology, Faculty of Biology, University of Duisburg-Essen, 45117 Essen, Germany.
Department of Aquatic Ecology, Faculty of Biology, University of Duisburg-Essen, 45117 Essen, Germany; Centre for Water and Environmental Research, University of Duisburg-Essen, 45117 Essen, Germany.
Sci Total Environ. 2019 May 1;663:841-851. doi: 10.1016/j.scitotenv.2019.01.288. Epub 2019 Jan 24.
Hydrological alteration of rivers is recognised as a major threat to lotic biodiversity acting at broad spatial scales, however, the effect size and pathways of hydrology are rarely quantified in comparison with other stressors such as land use and physico-chemistry. Here we present a multiple stressor study that aims to disentangle the effect sizes and pathways of hydrological alteration on benthic invertebrate community structure and functional metrics. Therefore, we analyse the following four multiple stressor groups: land use, hydrology, physical habitat structure, and physico-chemistry at 51 sites including 72 surveys in the German mountain range. Stressor data were contrasted to benthic invertebrate data using partial canonical correspondence analysis to quantify the community-level response and path analysis to investigate the cause-effect pathway structure of single stressors affecting benthic invertebrate metrics either directly or indirectly (i.e. mediated by other stressors). Hydrological stressors showed a strong impact on community structure, with its unique effects being more dominant than those of any other stressor group. Path analysis confirmed strong direct effects of hydrological stressors on biological metrics but revealed land use to be the most influential stressor group in terms of the sum of direct and indirect effects on biology. Notably, indirect land use effects are mediated by hydrology. Our findings suggest a key role of hydrological stressors in lotic ecosystem assessment, which, however, are rarely addressed in operational river monitoring and management. In light of the wide-spread availability of hydrological data from gauging stations throughout Europe, we plea for a better involvement of hydrological data in river basin management.
河流的水文变化被认为是对流水生物多样性的主要威胁，这种威胁作用于广阔的空间尺度，但与土地利用和理化性质等其他胁迫因素相比，水文变化的效应大小和途径很少被量化。在这里，我们提出了一项多胁迫因素研究，旨在厘清水文变化对底栖无脊椎动物群落结构和功能指标的效应大小和途径。因此，我们分析了以下四个多胁迫因素组：土地利用、水文学、物理生境结构和理化性质，在包括德国山脉在内的 51 个地点进行了 72 次调查。使用偏典范对应分析对比了胁迫因素数据和底栖无脊椎动物数据，以量化群落水平的响应，并用路径分析来调查影响底栖无脊椎动物指标的单个胁迫因素的因果关系结构，这些因素要么直接影响，要么间接影响（即通过其他胁迫因素介导）。水文胁迫因素对群落结构有很强的影响，其独特的影响比任何其他胁迫因素组都更为显著。路径分析证实了水文胁迫因素对生物指标有很强的直接影响，但表明土地利用是对生物学产生直接和间接影响总和的最具影响力的胁迫因素组。值得注意的是，间接的土地利用效应是由水文因素介导的。我们的研究结果表明，水文胁迫因素在流水生态系统评估中起着关键作用，而在实际的河流监测和管理中，这一因素很少被涉及。鉴于欧洲各地水文站都有广泛的水文数据，我们呼吁更好地将水文数据纳入流域管理。
