This multi-year pilot study evaluated a proposed field method for its effectiveness in the collection of a benthic macroinvertebrate sample adequate for use in the condition assessment of streams and rivers in the Neuquén Province, Argentina. A total of 13 sites, distributed across three rivers, were sampled. At each site, benthic macroinvertebrates were collected at 11 transects. Each sample was processed independently in the field and laboratory. Based on a literature review and resource considerations, the collection of 300 organisms (minimum) at each site was determined to be necessary to support a robust condition assessment, and therefore, selected as the criterion for judging the adequacy of the method. This targeted number of organisms was collected at all sites, at a minimum, when collections from all 11 transects were combined. Subsequent bootstrapping analysis of data was used to estimate whether collecting at fewer transects would reach the minimum target number of organisms for all sites. In a subset of sites, the total number of organisms frequently fell below the target when fewer than 11 transects collections were combined.Site conditions where < 300 organisms might be collected are discussed. These preliminary results suggest that the proposed field method results in a sample that is adequate for robust condition assessment of the rivers and streams of interest. When data become available from a broader range of sites, the adequacy of the field method should be reassessed.

中文翻译：

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生产足以评估阿根廷内乌肯省河流和溪流的样本所需的底栖大型无脊椎动物实地取样工作

这项为期多年的试点研究评估了拟议的现场方法在收集底栖大型无脊椎动物样本方面的有效性，该样本足以用于阿根廷内乌肯省的溪流和河流状况评估。总共采样了 13 个站点，分布在 3 条河流中。在每个地点，在 11 个横断面收集了底栖大型无脊椎动物。每个样品都在现场和实验室中独立处理。基于文献回顾和资源考虑，确定在每个地点收集 300 种生物（最少）对于支持稳健的条件评估是必要的，因此被选为判断该方法充分性的标准。当所有 11 个横断面的收集物结合在一起时，至少在所有地点收集了这个目标数量的生物体。随后的数据引导分析用于估计在更少的横断面收集是否会达到所有站点的最小目标生物数。在站点的子集中，当合并少于 11 个横断面集合时，有机体的总数经常低于目标。讨论了可能收集的有机体小于 300 的站点条件。这些初步结果表明，建议的现场方法产生的样本足以对感兴趣的河流和溪流进行稳健的条件评估。当从更广泛的地点获得数据时，应重新评估现场方法的充分性。当合并少于 11 个横断面集合时，生物体总数经常低于目标。讨论了可能收集到 300 个以下生物体的场地条件。这些初步结果表明，建议的现场方法产生的样本足以对感兴趣的河流和溪流进行稳健的条件评估。当从更广泛的地点获得数据时，应重新评估现场方法的充分性。当合并少于 11 个横断面集合时，生物体总数经常低于目标。讨论了可能收集到 300 个以下生物体的场地条件。这些初步结果表明，建议的现场方法产生的样本足以对感兴趣的河流和溪流进行稳健的条件评估。当从更广泛的地点获得数据时，应重新评估现场方法的充分性。