1. Freshwater ecosystems, providing valuable goods and services to humans, have been subjected to multiple human impacts, among which climate change plays a central role in threats to species. It is expected that protected areas, the cornerstone of biodiversity conservation efforts, will assume a decisive role in protecting freshwater species from the impacts of climate change.
2. This study assessed the effects of climate change on migratory fish of the second largest neotropical river basin, evaluating the effectiveness of protected areas in safeguarding fish species, and hence the ecological functions that they perform and the ecosystem resources that they provide. The present range of 23 migratory fish of economic interest in the Paraná–Paraguay basin was estimated and the responses to future climatic shifts projected to the middle and end of the 21st century were examined, quantifying predictive uncertainties.
3. Changes and losses of climatically suitable areas will trigger severe contractions in range, with the greatest impact on the most valuable species in commercial fishing, where range losses are likely to surpass 65% in the future. The main channel of the Upper Paraná River and tributaries of its left margin are projected to serve as climatic refuges for many species, and such regions are not affected by high predictive uncertainty. The results revealed that protected areas do not sufficiently protect migratory fish at present, and that they will continue to offer negligible protection in the face of climate change.
4. This study alerts decision makers to the potential damage to inland fishery resources from climate change and provides useful information to guide conservation strategies spatially. We advocate that the creation of new protected areas and the redesign of the existing network to encompass regions that maximize current and future occupancy of migratory fish are crucial to conserve the valuable ecological, societal, and economic benefits that they provide.

中文翻译：

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南美洲第二大河流域洄游鱼类的保护取决于新保护区的建立

1. 为人类提供有价值的商品和服务的淡水生态系统受到了多种人类影响，其中气候变化在对物种构成威胁方面起着核心作用。预计作为生物多样性保护工作基石的保护区将在保护淡水物种免受气候变化影响方面发挥决定性作用。
2. 本研究评估了气候变化对第二大新热带河流域洄游鱼类的影响，评估了保护区在保护鱼类物种方面的有效性，从而评估了它们执行的生态功能和它们提供的生态系统资源。估计了巴拉那-巴拉圭盆地 23 种具有经济利益的洄游鱼类的当前范围，并检查了对预计到 21 世纪中叶和末期的未来气候变化的反应，量化了预测的不确定性。
3. 气候适宜区域的变化和损失将引发范围的严重收缩，对商业捕鱼中最有价值的物种影响最大，未来范围损失可能超过 65%。上巴拉那河的主要河道及其左边缘的支流预计将成为许多物种的气候避难所，这些地区不受高度预测不确定性的影响。结果表明，保护区目前对洄游鱼类的保护不够，在气候变化面前，它们将继续提供微不足道的保护。
4. 这项研究提醒决策者气候变化对内陆渔业资源的潜在损害，并提供有用的信息来指导空间保护战略。我们主张创建新的保护区和重新设计现有网络以涵盖最大限度地提高当前和未来洄游鱼类占有率的区域，这对于保护它们提供的宝贵生态、社会和经济利益至关重要。