Aquatic organisms with different adaptations are used as indicators in physical habitat simulation system models. Those adaptations are critical for determining the shape of the weighted usable area/width curve and for recommending values of environmental flows. The main objective of this study is to compare the use of benthic native species (Astroblepus taczanowskii and Astroblepus vanceae) versus the introduced Oncorhynchus mykiss (rainbow trout) as target indicators for PHABSIM modelling in the Andean–Amazon piedmont rivers. We used adjusted probability distribution functions with L‐moments analyses for developing curves of use and preference to evaluate the efficiency of each indicator. Two hydraulic modelling sections were established in the Ulcumayo River with 21 and 27 cross sections, respectively. Native benthic species are usually dominant but scarcely used as focus organisms for environmental flows modelling. These species are associated with fast running and shallow waters, which makes them potentially more sensitive to the effects of flow reduction. Our results indicated that the native species were more restricted to velocity and depth than O. mykiss. Using selection curves in PHABSIM modelling, it is required between 10% to 94% of the mean monthly flow to preserve 90% of the available habitat for Astroblepus during the dry season (May to November). In contrast, rainbow trout requires 5% to 88% of the mean monthly flow. We conclude that a multispecies approach is useful for determining the required environmental instream flows contributing to a better sustainable condition for the Neotropical mountain rivers.

中文翻译：

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在秘鲁安第斯山脉-亚马逊河中，以底栖鱼类或浮游鱼类为指标的物理栖息地模拟系统建模结果的差异

具有不同适应性的水生生物被用作物理栖息地模拟系统模型的指标。这些调整对于确定加权可用面积/宽度曲线的形状以及建议环境流量的值至关重要。这项研究的主要目的是比较底栖原生种（Atroblepus taczanowskii和Astroblepus vanceae）与引进的Oncorhynchus mykiss的使用（虹鳟鱼）作为安第斯–亚马逊山麓河流中PHABSIM建模的目标指标。我们将调整后的概率分布函数与L矩分析一起使用，以建立使用和偏好曲线，以评估每个指标的效率。在乌尔库马约河中建立了两个水力模型部分，分别具有21和27个横截面。原生底栖生物通常占主导地位，但很少用作环境流量模拟的重点生物。这些物种与快速流域和浅水区有关，这使它们可能对流量减少的影响更加敏感。我们的结果表明，本地物种比O. mykiss对速度和深度的限制更大。。使用PHABSIM建模中的选择曲线，在干旱季节（5月至11月），需要平均月流量的10％至94％之间的流量才能为Astroblepus保护90％的可用栖息地。相反，虹鳟鱼需要平均月流量的5％至88％。我们得出结论，采用多物种方法可用于确定所需的环境溪流，从而为新热带山区河流创造更好的可持续条件。