DISSERTATION RESEACH: Thermal Fragmentation and Genetic Differentiation of Fish Populations in a Riverine Landscape

论文研究：河流景观中鱼类种群的热破碎和遗传分化

• 批准号: 0420338
• 负责人: N. Leroy Poff
• 金额: $ 1.15万
• 依托单位: Colorado State University
• 依托单位国家: 美国
• 项目类别: Standard Grant
• 财政年份: 2004
• 资助国家: 美国
• 起止时间: 2004-09-01 至 2005-08-31
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=0420338&HistoricalAwards=false
• 关键词: DISSERTATION; RESEACH; Thermal; Fragmentation; Genetic

The great utility of running waters has resulted in the extensive exploitation of streams and rivers throughout the world, a process greatly facilitated by the construction of hundreds of thousands of dams globally. It is well established that dams have a fragmenting effect on the landscape by blocking the movement of individuals between essential habitats required to complete their life cycle (e.g., salmon species in the Pacific Northwest). Moreover, many dams throughout the world have dramatically modified downstream environments by selectively releasing cold water from reservoirs in order to establish productive trout fisheries in the tailwater reaches of the dammed river. Our recent research in southeastern United States shows that the conversion from warmwater to coldwater habitats can result in significant losses to fish populations in the tailwaters, whereas the adjoining, warmwater tributaries provide thermal refugia and contain extremely dense and diverse fish assemblages. These results led to the hypothesis that coldwater-release dams may have an additional fragmenting effect by restricting fish movement through the cold tailwaters, which over time could lead to the genetic differentiation of the tributary fish populations. We address this hypothesis by examining the genetic structure of 3 fish species that exhibit different thermal preferences and mobility's in a series of tributaries that are separated by different tailwater temperatures and geographic distances. This is the first examination of how human-induced thermal barriers to movement may shape the genetic structure of fish populations in fragmented tributaries, and has important implications for focusing future management and conservation efforts aimed at improving the thermal connectivity of warmwater tributaries in tailwater environments in order to ensure the long-term persistence of warmwater fish assemblages.

流动沃茨的巨大效用导致了世界各地对溪流和河流的广泛开发，全球数十万座水坝的建设极大地促进了这一进程。 众所周知，水坝阻碍了个体在完成其生命周期所需的基本栖息地之间的移动，从而对景观产生破碎化影响（例如，太平洋西北部的鲑鱼物种）。 此外，世界各地的许多水坝通过选择性地从水库中释放冷水，以在筑坝河流的尾水区建立富有成效的鳟鱼渔业，从而极大地改变了下游环境。 我们最近在美国东南部的研究表明，从温水到冷水栖息地的转换可能会导致尾水鱼类种群的重大损失，而毗邻的温水支流提供热避难所，并包含非常密集和多样化的鱼类组合。 这些结果导致的假设，冷水释放大坝可能有一个额外的碎片化的影响，限制鱼类运动通过冷尾水，随着时间的推移可能会导致支流鱼类种群的遗传分化。 我们通过研究3种鱼类的遗传结构来解决这一假设，这些鱼类在一系列由不同尾水温度和地理距离分开的支流中表现出不同的热偏好和流动性。 这是第一次检查人类引起的热障碍运动可能会塑造鱼类种群的遗传结构在支离破碎的支流，并有重要的影响，重点未来的管理和保护工作，旨在改善尾水环境中的暖水支流的热连通性，以确保长期持久的暖水鱼类组合。