Dams are among the most prevalent and extreme alterations humans have perpetrated on fluvial systems. The dramatic physical and biological changes caused by dams have been synthesized for many aquatic faunal groups, but not for crayfishes. In addition, invasive crayfish species are an increasing threat to global biodiversity, and dams have both costs and benefits with respect to crayfish invasions. North American crayfishes have imperiled native crayfishes in Europe, largely by hosting and spreading the crayfish plague pathogen Aphanomyces astaci that is lethal to European crayfishes. The differential effects of A. astaci on North American vs. European crayfishes contribute to differences between the continents in the costs and benefits of dams. We reviewed literature on both the detrimental and beneficial effects of dams on crayfishes, with emphasis on conservation of European crayfishes. We also suggested additional potential dam effects that warrant investigation. Our review illustrates the challenges and opportunities dams create for crayfish conservation. Dams create detrimental effects to native crayfishes, including reducing suitable habitats necessary for native habitat-specialist species and creating habitats suitable for non-native habitat-generalist species; fragmenting crayfish populations; and reducing species' ability to recolonize upstream habitats. Conversely, dams can have beneficial effects by creating barriers that slow or halt upstream invasions by non-native crayfishes and spread of the crayfish plague. The complexity of the issues and the limited ecological information available highlights the need for future studies on the effects of dams on crayfishes. Crayfishes are one of the most imperiled groups of aquatic fauna globally; therefore, understanding the beneficial and detrimental effects of dams is essential for effective conservation of many crayfish species.

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回顾大坝对本地和入侵小龙虾的影响说明了保护规划的复杂选择

大坝是人类对河流系统进行的最普遍和极端的改造之一。水坝引起的巨大物理和生物变化已被综合用于许多水生动物群，但不适用于小龙虾。此外，入侵的小龙虾物种对全球生物多样性的威胁越来越大，而水坝在小龙虾入侵方面既有成本也有收益。北美小龙虾已经危及欧洲本土小龙虾，主要是通过寄生和传播小龙虾瘟疫病原体丝囊菌这对欧洲小龙虾是致命的。的差异效应A. astaci北美与欧洲小龙虾的差异导致了各大洲在水坝成本和收益方面的差异。我们回顾了有关水坝对小龙虾的有害和有益影响的文献，重点是欧洲小龙虾的保护。我们还提出了值得调查的其他潜在大坝影响。我们的评论说明了水坝为小龙虾保护带来的挑战和机遇。大坝对本地小龙虾造成不利影响，包括减少本地栖息地专业物种所需的合适栖息地，以及创造适合非本地栖息地通才物种的栖息地；分散小龙虾种群；并降低物种重新定居上游栖息地的能力。反过来，水坝可以通过设置屏障来减缓或阻止非本地小龙虾的上游入侵和小龙虾瘟疫的传播，从而产生有益的影响。问题的复杂性和可用的生态信息有限突出表明未来需要研究水坝对小龙虾的影响。小龙虾是全球最危险的水生动物群之一。因此，了解水坝的有益和有害影响对于有效保护许多小龙虾物种至关重要。