1. River regulation has extensively changed the ecology and hydrology of rivers worldwide, particularly downstream of dams, affecting the viability of freshwater species. The platypus (Ornithorhynchus anatinus) is a semiaquatic monotreme, endemic to eastern Australia, with a distribution overlapping Australia’s most regulated rivers.
2. Dams and changes to flow regimes have affected critical platypus habitat, yet our understanding of the impacts of these threatening processes on platypus ecology remains poor. Over a period of 3 years (2016–2018), platypuses were surveyed across three regions (Upper Murray, Snowy, and Border river regions), above and below large dams, and in adjacent unregulated rivers, comparing captures, demographics, abundances, and densities. We hypothesized that platypus captures and abundances would be lower downstream of dams, owing to altered flow regimes that have secondary impacts on the demographics of these populations.
3. In the Upper Murray Rivers region, captures were significantly lower in the Mitta Mitta River below Dartmouth Dam, compared with captures upstream of the dam and the unregulated Ovens River, probably reflecting significant alteration to the seasonality and temperature of flows caused by the dam. Conversely, there were no significant differences in captures or abundance and density estimates above and below the dams in the Snowy or Border river regions, where the extent of regulation was less severe, probably as a result of restoration efforts in recent years on some rivers.
4. Low proportions of juveniles on the Snowy River and Mitta Mitta River downstream of the dams, compared with upstream, raises concerns of other impacts of altered flow regimes to platypus breeding success and juvenile survival, given the sensitivity of juveniles to unseasonably high flows.
5. The results highlighted the potential impact of river regulation, with direct implications for the management of regulated rivers, providing opportunities to mitigate impacts through improved management of the seasonality and temperature of flows, to the benefit of platypuses and other freshwater species.

中文翻译：

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洞察力：河流管制对鸭嘴兽种群的可变影响和影响

1. 河流管制已广泛改变了世界范围内河流的生态和水文状况，特别是在大坝的下游，影响了淡水物种的生存能力。鸭嘴兽（Ornithorhynchus anatinus）是一种半水生的单生动物，特有于澳大利亚东部，其分布与澳大利亚最受管制的河流重叠。
2. 大坝和流动方式的变化影响了关键的鸭嘴兽栖息地，但是我们对这些威胁性过程对鸭嘴兽生态学影响的理解仍然很差。在三年（2016-2018年）期间，对大型水坝上下的三个区域（默里河上游，斯诺伊河和边境河地区）以及相邻未管制河流中的鸭嘴兽进行了调查，比较了捕获物，人口统计资料，丰度和密度。我们假设鸭嘴兽的捕获量和丰度将在大坝下游降低，这是由于流动方式的改变对这些人口的人口统计产生了二次影响。
3. 在上游墨累河地区，达特茅斯水坝以下的米塔米塔河的捕获量明显低于大坝上游和未经调节的烤箱河的捕获量，这可能反映了由大坝引起的水流季节和温度的重大变化。相反，在斯诺伊河或边境河地区，大坝上方和下方的捕获量，丰度和密度估算值均无显着差异，那里的管制程度较轻，这可能是由于近年来对某些河流的恢复所作的努力。
4. 与上游相比，大坝下游的斯诺伊河和米塔米塔河上的幼鱼比例较低，这引起了人们对流动方式改变对鸭嘴兽繁殖成功和幼年生存的其他影响的关注，因为幼鱼对异常高流量的敏感性。
5. 结果强调了河流管制的潜在影响，这直接影响了受管制河流的管理，为改善鸭嘴兽和其他淡水物种的利益提供了机会，可以通过对流量的季节性和温度进行更好的管理来减轻影响。