School of Biology and Environmental Science, University College Dublin, Belfield, Dublin 4, Ireland.
School of Geography and UCD Earth Institute, University College Dublin, Belfield, Dublin 4, Ireland.
Sci Total Environ. 2016 Oct 15;568:1092-1101. doi: 10.1016/j.scitotenv.2016.06.168. Epub 2016 Jun 30.
An ongoing research challenge is the detection of biological responses to elevated sediment and the identification of sediment-specific bioassessment metrics to evaluate these biological responses. Laboratory mesocosms and field observations in rivers in Ireland were used to evaluate the relationship between a range of biological and sediment metrics and to assess which biological metrics were best at discerning the effects of excess sediment on macroinvertebrates. Results from the mesocosm study indicated a marked decrease in the abundance of sensitive taxa with increasing sediment surface cover. % EPT (Ephemeroptera, Plecoptera, Trichoptera) and % E abundances exhibited the strongest negative correlation with sediment surface cover in the mesocosm study. The field study revealed that % EPT abundance was most closely correlated with % sediment surface cover, explaining 13% of the variance in the biological metric. Both studies revealed weaker relationships with a number of other taxonomy-based metrics including total taxon abundance, total taxon richness and moderate relationships with the Proportion of Sediment-sensitive Invertebrates metric (PSI). All trait-based metrics were poorly correlated with sediment surface cover in the field study. In terms of sediment metrics, % surface cover was more closely related to biological metrics than either re-suspendable sediment or turbidity. These results indicate that % sediment surface cover and % EPT abundance may be useful metrics for assessing the effect of excessive sediment on macroinvertebrates. However, EPT metrics may not be specific to sediment impact and therefore when applied to rivers with multiple pressures should be combined with observations on sediment cover.
目前的研究挑战之一是检测沉积物升高对生物的影响，并确定特定于沉积物的生物评估指标来评估这些生物反应。本研究使用爱尔兰河流的实验室中尺度模型和现场观测来评估一系列生物和沉积物指标之间的关系，并评估哪些生物指标最能区分过量沉积物对大型无脊椎动物的影响。中尺度模型研究的结果表明，随着沉积物表面覆盖率的增加，敏感类群的丰度明显下降。在中尺度模型研究中，% EPT（蜉蝣目、襀翅目、毛翅目）和% E 的丰度与沉积物表面覆盖率呈最强的负相关。现场研究表明，% EPT 的丰度与% 沉积物表面覆盖率最密切相关，解释了生物指标中 13%的变异性。这两项研究都揭示了与其他一些基于分类学的指标的较弱关系，包括总分类群丰度、总分类群丰富度以及与敏感类群比例（PSI）的中度关系。所有基于特征的指标在现场研究中与沉积物表面覆盖率的相关性都较差。就沉积物指标而言，%表面覆盖率与生物指标的关系比可再悬浮沉积物或浊度更密切。这些结果表明，% 沉积物表面覆盖率和% EPT 丰度可能是评估过量沉积物对大型无脊椎动物影响的有用指标。然而，EPT 指标可能不是专门针对沉积物影响的，因此在应用于存在多种压力的河流时，应与沉积物覆盖的观察结果结合使用。
