Abstract In this study, we propose a novel framework combining spatially explicit population viability analysis and optimization for prioritizing fish passage barrier mitigation decisions. Our model aims to maximize the equilibrium population size, or alternatively minimize the extinction risk, of a target fish species subject to a budget on the total cost of barrier mitigation. A case study involving a wild coho salmon (Oncorhynchus kisutch) population from the Tillamook basin, Oregon, USA is used to illustrate the benefits of our approach. We consider two different spawning adult dispersal patterns, river and reach level homing, as well as straying. Under density dependent population growth, we find that homing behavior type has a significant effect on barrier mitigation decisions. In particular, with reach homing, our model produces virtually the same population sizes as a more traditional barrier prioritization procedure designed to maximize accessible habitat. With river homing, however, we find that it is not necessary to remove all barriers in order to maximize equilibrium population size. Indeed, a stochastic version of our model reveals that removing all barriers actually results in a marginal increase in quasi-extinction risk. We hypothesize that this is due to a population thinning effect of barriers, resulting in a surplus of recruits in areas of low spawner density. Our findings highlights the importance of considering spatiotemporal fish population dynamics in river connectivity restoration planning. By adding greater biological realism, models such as ours can help conservation managers to more strategically allocate limited resources, resulting in both cost savings and improved population status for a focal species.

中文翻译：

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时空鱼类种群动态在障碍缓解规划中的重要性

摘要 在这项研究中，我们提出了一种新的框架，结合了空间显性种群生存力分析和优化，用于优先考虑鱼类通道障碍缓解决策。我们的模型旨在最大化平衡种群规模，或者最小化目标鱼类的灭绝风险，但要遵守障碍缓解总成本的预算。一个案例研究涉及来自美国俄勒冈州蒂拉穆克盆地的野生银鲑鱼 (Oncorhynchus kisutch) 种群，用于说明我们方法的好处。我们考虑两种不同的产卵成虫散布模式，河流和到达水平归巢，以及流浪。在密度依赖的人口增长下，我们发现归巢行为类型对障碍缓解决策有显着影响。特别是，随着到达归位，我们的模型产生的种群规模几乎与更传统的屏障优先程序相同，该程序旨在最大限度地扩大可及的栖息地。然而，通过河流归巢，我们发现没有必要消除所有障碍以最大化平衡种群规模。事实上，我们模型的随机版本表明，消除所有障碍实际上会导致准灭绝风险的边际增加。我们假设这是由于屏障的人口稀少效应，导致在低产卵密度地区新兵过剩。我们的研究结果强调了在河流连通性恢复规划中考虑时空鱼类种群动态的重要性。通过增加更大的生物现实主义，像我们这样的模型可以帮助保护管理者更有策略地分配有限的资源，