COLLABORATIVE RESEARCH: Ecological and evolutionary dynamics of secondary contact

随着大坝的拆除，全国各地的河流和溪流正恢复到原来的流动模式，其中许多大坝是几个世纪前修建的，目的是为构成殖民经济基础的小磨坊提供能源。该项目利用计划中的大坝拆除，将分离了近四个世纪的鱼类种群连接起来，以研究这些最近分化的鱼类种群之间二次接触的生态和进化后果，这些鱼类种群可能会杂交，但也可能竞争。这项工作的成果将有助于养护和管理迁徙鱼类，这是沿海淡水和海洋生境的关键资源，也是密集恢复和养护工作的重点。研究人员将与州管理人员、康涅狄格州能源和环境保护部、湖泊协会和土地信托基金合作，确定恢复迁徙人口的后果，提供对妻子恢复至关重要的信息，并就河流恢复的后果教育当地社区。该项目将培训一名博士后研究员以及研究生和本科生参与一个跨学科项目，该项目依赖于先进的遗传学技术、野外采样以及操纵性的现场和实验室实验。耶鲁大学现有的一个项目将支持未被充分代表的少数族裔本科生参与夏季研究。培训将包括研究的更广泛的科学背景、研究方法、数据分析、书面和口头项目报告，以及直接与公众接触，介绍研究的社会效益。这个项目利用全湖恢复项目来了解最近分化的妻子血统之间二次接触的生态和进化动态。建造水坝造成的孤立导致了两种不同的妻子生活史形式：在湖泊和沿海海洋之间移动的祖先滨水形式和居住在湖泊中的内陆形式。这个项目将结合先进的基因组学、小规模实验、全湖观察和实验来记录和了解二次接触的后果，当大坝拆除允许顺水母重新引入包含陆上形式的湖泊时。与拆除大坝的州机构密切合作，将使调查人员能够从二次接触开始就进行研究。该项目涉及应对二次接触的三个阶段：浮游生物群落和营养物质流动的快速生态变化，无脊椎动物种群对新生态条件的快速进化反应，以及可能导致杂交和较长期的妻子进化和局部适应的两个妻子形态之间的相互作用。这些反应中的第一个--湖泊群落的生态变化--对于解释由此产生的进化变化至关重要。该项目的独特之处在于，它能够在两个时间尺度上捕捉二次接触的后果。这些结果将难得地深入了解二次接触后野外种群的生态和进化过程之间的反馈，对生态系统功能和恢复的生态系统中生物多样性的维持具有重要影响。

Rivers and streams across the country are being restored to their original flow patterns by the removal of dams, many of which were constructed centuries ago to provide energy for small mills that formed the basis of colonial economies. This project takes advantage of planned dam removals that will connect fish populations that have been separated for nearly four centuries, in order to study the ecological and evolutionary consequences of secondary contact between these recently divergent fish populations, which may interbreed but also may compete. Results from this work will contribute to the conservation and management of migratory alewife fish, a critical resource in coastal freshwater and marine habitats and the focus of intensive restoration and conservation efforts. Researchers will work collaboratively with state managers, the Connecticut Department of Energy and Environmental Protection, lake associations, and land trusts to determine the consequences of restoring migratory populations, provide information vital to alewife recovery, and educate local communities on the consequences of river restoration. The project will train a postdoctoral researcher along with graduate and undergraduate students in an interdisciplinary project that relies on advanced genetics techniques, field sampling, and manipulative field and laboratory experiments. An existing program at Yale University will support involvement of underrepresented minority undergraduate students in summer research. Training will include the broader scientific context of the research, research methods, data analysis, written and oral project reports, and direct involvement with the public to present the societal benefits of the research. This project takes advantage of whole-lake restoration projects to understand the ecological and evolutionary dynamics of secondary contact between recently diverged lineages of alewife. Isolation caused by construction of dams has resulted in two divergent alewife life history forms: the ancestral anadromous form that moves between lakes and the coastal ocean and a landlocked form that is resident in lakes. This project will combine advanced genomics, small-scale experiments, and whole-lake observations and experiments to document and understand the consequences of secondary contact, when dam removal allows reintroduction of anadromous alewife into lakes that contain the land-locked form. Close collaboration with the state agency that removes dams will allow the investigators to study secondary contact from its initiation. The project addresses three stages in response to secondary contact: rapid ecological change in planktonic communities and nutrient flux, rapid evolutionary responses in invertebrate populations in response to novel ecological conditions, and interactions between the two alewife morphs that may result in hybridization and, over the longer-term, alewife evolution and local adaptation. The first of these responses - ecological changes in lacustrine communities - is essential in order to interpret the evolutionary changes that result. The project is unique in its ability to capture the consequences of secondary contact on both time scales. Results will provide rare insight into feedbacks between ecological and evolutionary processes in field populations following secondary contact with important implications for ecosystem function and the maintenance of biodiversity in restored ecosystems.