Valenzuela-Aguayo Francisca, McCracken Gregory R, Manosalva Aliro, Habit Evelyn, Ruzzante Daniel E
Laboratorio de Ecología y Conservación de Peces Departamento de Sistemas Acuáticos Facultad de Ciencias Ambientales y Centro EULA Universidad de Concepción Concepción Chile.
Department of Biology Dalhousie University Halifax NS Canada.
Evol Appl. 2019 Dec 9;13(4):794-807. doi: 10.1111/eva.12901. eCollection 2020 Apr.
An understanding of how genetic variability is distributed in space is fundamental for the conservation and maintenance of diversity in spatially fragmented and vulnerable populations. While fragmentation can occur from natural barriers, it can also be exacerbated by anthropogenic activities such as hydroelectric power plant development. Whatever the source, fragmentation can have significant ecological effects, including disruptions of migratory processes and gene flow among populations. In Chile, the Biobío River basin exhibits a high degree of habitat fragmentation due to the numerous hydroelectric power plants in operation, the number of which is expected to increase following new renewable energy use strategies. Here, we assessed the effects of different kinds of barriers on the genetic structure of the endemic freshwater fish , knowledge that is critically needed to inform conservation strategies in light of current and anticipated further fragmentation initiatives in the system. We identified eight genetic units throughout the entire Biobío system with high effective sizes. A reduced effective size estimate was, however, observed in a single population located between two impassable barriers. Both natural waterfalls and human-made dams were important drivers of population differentiation in this system; however, dams affect genetic diversity differentially depending on their mode of operation. Evidence of population extirpation was found in two river stretches limited by upstream and downstream dams. Significant gene flow in both directions was found among populations not separated by natural or anthropogenic barriers. Our results suggest a significant vulnerability of populations to future dam development and demonstrate the importance of studying basin-wide data sets with genetic metrics to understand the strength and direction of anthropogenic impacts on fish populations.
了解遗传变异如何在空间中分布，对于保护和维持空间上碎片化且脆弱的种群的多样性至关重要。虽然碎片化可能源于自然屏障，但也可能因水电厂开发等人为活动而加剧。无论其来源如何，碎片化都会产生重大的生态影响，包括迁徙过程和种群间基因流动的中断。在智利，比奥比奥河流域由于运营中的众多水电厂而呈现出高度的栖息地碎片化，随着新的可再生能源利用战略的实施，水电厂数量预计还会增加。在此，我们评估了不同类型的屏障对特有淡水鱼遗传结构的影响，鉴于该系统当前及预期的进一步碎片化举措，这一知识对于制定保护策略至关重要。我们在整个比奥比奥系统中识别出八个具有高有效种群大小的遗传单元。然而，在位于两个无法逾越的屏障之间的单个种群中观察到有效种群大小估计值降低。天然瀑布和人工水坝都是该系统中种群分化的重要驱动因素；然而，水坝对遗传多样性的影响因其运行方式而异。在受上游和下游水坝限制的两段河流中发现了种群灭绝的证据。在未被自然或人为屏障分隔的种群之间发现了双向的显著基因流动。我们的结果表明种群对未来水坝开发具有显著的脆弱性，并证明了利用遗传指标研究全流域数据集以了解人为对鱼类种群影响的强度和方向的重要性。
