1. The Sierras Pampeanas Centrales, one of the most important extra‐Andean mountain systems of Argentina, harbour endemic and threatened amphibian species. In the past century, two alien predatory fish species (brook trout and rainbow trout) were introduced into rivers and streams of the area where amphibian species breed.
2. We hypothesized that the presence of trout would adversely affect the distribution of native amphibians in streams of the area. To test this hypothesis, the habitat requirements of trout and native amphibians were compared, and the effect of trout presence on amphibian occurrence was evaluated.
3. Transects (n = 126) were surveyed along rivers and streams in high‐altitude grasslands of the area, and the occurrences of trout and amphibians and habitat variables were recorded.
4. The habitat requirements of each species were compared using multivariate methods. Generalized linear mixed models were used to evaluate whether the occurrence of amphibians depends on trout, habitat variables or both. The distribution of each species between streams orders was assessed.
5. The results showed that the presence of trout was the main factor conditioning the distribution of two endemic amphibian species (Boana cordobae and Odontophrynus achalensis) in basins of the study area.
6. This threat needs to be incorporated urgently into action plans to guide conservation efforts towards the management of trout populations.

中文翻译：

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阿根廷山脉中的鳟鱼入侵导致上游两栖动物濒临灭绝

1. 阿根廷最重要的安第斯山脉之外的山脉系统之一-山脉潘帕尼亚斯中央山脉（Sierras Pampeanas Centrales）拥有地方性和濒临灭绝的两栖动物。在过去的一个世纪中，将两种外来掠食性鱼类（溪鳟和虹鳟）引入了两栖动物繁殖地区的河流和溪流中。
2. 我们假设鳟鱼的存在会对当地两栖动物在该地区河流中的分布产生不利影响。为了验证该假设，比较了鳟鱼和天然两栖动物的栖息地需求，并评估了鳟鱼的存在对两栖动物发生的影响。
3. 在该地区高海拔草地的河流和溪流中对横断面（n = 126）进行了调查，并记录了鳟鱼和两栖动物的发生以及栖息地的变量。
4. 使用多元方法比较了每个物种的栖息地需求。使用广义线性混合模型来评估两栖动物的发生是否取决于鳟鱼，生境变量或两者。评估了溪流顺序之间每种物种的分布。
5. 结果表明，鳟鱼的存在是制约研究区流域内两个特有的两栖类物种（Boana cordobae和Odontophrynus achalensis）分布的主要因素。
6. 必须将这一威胁紧急纳入行动计划，以指导养护努力管理鳟鱼种群。