Reliable methods for assessing the ecological status of degraded rivers are essential for evaluating restoration efforts in lotic habitats. Several methods are based on biological indicators, such as benthic macroinvertebrates. The Hester–Dendy multi-plate sampler is a commonly used tool for sampling macroinvertebrates, but its performance under different environmental conditions is not well understood. In a laboratory experiment, we assessed if fluctuating and increasing water velocity influences the performance of Hester–Dendy samplers, by studying colonization of the samplers in relation to a pre-determined composition of benthic macroinvertebrates. Biodiversity (Shannon-Wiener index) of colonizing macroinvertebrates was higher in a constant than in a fluctuating flow treatment, but there was no effect on the number of colonizing individuals. The results suggest a potential bias in the interpretation of biodiversity data from sites with sub-daily flow changes, for example, downstream of hydropeaking power plants.

中文翻译：

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Hester-Dendy 大型无脊椎动物采样器在波动流中的适用性

评估退化河流生态状况的可靠方法对于评估河流栖息地的恢复工作至关重要。有几种方法基于生物指标，例如底栖大型无脊椎动物。Hester-Dendy 多板采样器是大型无脊椎动物采样的常用工具，但其在不同环境条件下的性能尚不清楚。在实验室实验中，我们通过研究采样器的定植与底栖大型无脊椎动物的预定组成相关，评估了波动和增加的水速是否会影响 Hester-Dendy 采样器的性能。定植大型无脊椎动物的生物多样性（香农-维纳指数）在恒定比波动流处理中更高，但对定植个体数量没有影响。