We developed MMI models that combine responses of fish and benthic macroinvertebrates for the evaluation of the biotic integrity of streams. The MMI was developed using a dataset covering stream sampling sites in the South of Brazil. Reference streams were identified based on the physical and chemical conditions and riparian vegetation. Thirty-four metrics were calculated and evaluated for their range, redundancy, and responsiveness to the environmental perturbation. We applied a robust approach to select the most sensitive metrics and MMI models based on the complexity and ability of the index in distinguishing impacted and reference sites. The four best MMI models selected are composed of different combinations of the eight metrics: % fish herbivorous, fish evenness, fish abundance, % macroinvertebrate shredder; % macroinvertebrate predator; % macroinvertebrate tolerant, % macroinvertebrate swimmer, and % macroinvertebrate burrower. All of the MMI models selected presented good performance in distinguishing reference streams from those impacted by different forms of land use. This study is one of the few attempts to use more than one biological assemblage in a single-multimetric index. Accordingly, we believe that the unified MMI we developed could be a useful tool to assist in the conservation and management of water resources in Neotropical regions, specially, in the implementation of ecological integrity tools more cost-effectively.

中文翻译：

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基于鱼类和大型无脊椎动物组合评估巴西南部河流生物状况的统一多指标指数

我们开发了 MMI 模型，该模型结合了鱼类和底栖大型无脊椎动物的反应，用于评估河流的生物完整性。MMI 是使用覆盖巴西南部河流采样点的数据集开发的。根据物理和化学条件和河岸植被确定参考河流。计算并评估了 34 个指标的范围、冗余和对环境扰动的响应。我们应用了一种稳健的方法，根据索引区分受影响站点和参考站点的复杂性和能力，选择最敏感的指标和 MMI 模型。选定的四个最佳 MMI 模型由八个指标的不同组合组成：鱼类食草性百分比、鱼类均匀度、鱼类丰度、大型无脊椎动物切碎机百分比；% 大型无脊椎动物捕食者；% 大型无脊椎动物耐受性、% 大型无脊椎动物游泳者和 % 大型无脊椎动物挖洞者。选择的所有 MMI 模型在区分参考流和受不同土地利用形式影响的流方面表现良好。这项研究是为数不多的在单一多指标指数中使用多个生物组合的尝试之一。因此，我们相信我们开发的统一 MMI 可以成为帮助新热带地区水资源保护和管理的有用工具，特别是在更具成本效益的情况下实施生态完整性工具。这项研究是为数不多的在单一多指标指数中使用多个生物组合的尝试之一。因此，我们相信我们开发的统一 MMI 可以成为帮助新热带地区水资源保护和管理的有用工具，特别是在更具成本效益的情况下实施生态完整性工具。这项研究是为数不多的在单一多指标指数中使用多个生物组合的尝试之一。因此，我们相信我们开发的统一 MMI 可以成为帮助新热带地区水资源保护和管理的有用工具，特别是在更具成本效益的情况下实施生态完整性工具。