Hawley K L, Thaulow J, Urke H A, Kristensen T, Barson N J, Haugen T O
Norwegian Institute for Water Research Oslo Norway.
Faculty of Environmental Sciences and Natural Resource Management The Norwegian University of Life Sciences Ås Norway.
Evol Appl. 2025 Jul 8;18(7):e70130. doi: 10.1111/eva.70130. eCollection 2025 Jul.
Dispersal impacts individual fitness and influences local dynamics, stability and adaptation in interconnected populations. Anadromous salmonid fishes are renowned for their precise homing and adaptations to local aquatic environments, while navigating between multiple connected habitats. However, recent studies have demonstrated considerable straying among systems, generating metapopulation dynamics among connected subpopulations or demes. Salmonids constitute valuable economic and ecological resources, yet many populations are declining due to multifaceted anthropogenic-induced disturbances. This context of reduced populations inhabiting altered environments may impact both population viability and dispersal. To explore if metapopulation processes are present among impacted neighbouring populations of anadromous brown trout (), a 4-year study of individual ( = 84) dispersal behaviour (using biotelemetry) and genetic analysis was conducted in four populations, connected by an extensive (> 200 km), semi-enclosed fjord system, Sognefjorden, Norway. To estimate the demographic status of each study population, life-table matrices were built, from which a potential source-sink structure among demes could be identified. Sognefjorden brown trout formed a metapopulation consisting of multiple sink populations, primarily supplemented from a single source. Only one population exhibited intrinsic growth (i.e., > 1), with excess recruits in this population attributed to high survival within the fjord. Among potential spawners, dispersal movements were performed by 55% of the total population, with individual age and migration extent affecting the probability of this behaviour. Successful dispersal (straying) was performed by 25% of the total spawning population. The extensive hydroscape generated directional gene flow from the innermost to outermost populations, with the highest rates observed among neighbouring populations. Although most dispersal resulted in unsuccessful spawning events and/or was not intended for spawning (e.g., conducted for overwintering purposes), connectivity among population demes was significant. This connectivity likely enhances the overall resilience of the metapopulation to variation and shifts in contemporary conditions within the fjord.
扩散影响个体适合度，并影响相互连接的种群中的局部动态、稳定性和适应性。溯河产卵的鲑科鱼类以其精确的归巢能力以及在多个相连栖息地之间洄游时对当地水生环境的适应性而闻名。然而，最近的研究表明，不同系统之间存在相当数量的偏离，从而在相连的亚种群或同类群之间产生了集合种群动态。鲑科鱼类是宝贵的经济和生态资源，但由于多方面的人为干扰，许多种群数量正在下降。在环境发生改变的情况下，种群数量减少可能会影响种群生存力和扩散。为了探究受影响的相邻溯河产卵褐鳟种群之间是否存在集合种群过程，在挪威松恩峡湾一个广泛（>200公里）、半封闭的峡湾系统连接的四个种群中，对个体（n = 84）的扩散行为（使用生物遥测技术）和遗传分析进行了为期4年的研究。为了估计每个研究种群的种群统计学状况，构建了生命表矩阵，从中可以识别出同类群之间潜在的源-汇结构。松恩峡湾褐鳟形成了一个由多个汇种群组成的集合种群，主要由单一源种群补充。只有一个种群表现出内在增长（即λ>1），该种群中多余的补充个体归因于峡湾内的高存活率。在潜在产卵者中，55%的个体进行了扩散移动，个体年龄和洄游范围影响了这种行为的概率。25%的总产卵种群成功进行了扩散（偏离）。广阔的水文景观产生了从最内陆种群到最外围种群的定向基因流，相邻种群之间的基因流速率最高。尽管大多数扩散导致产卵事件失败和/或并非用于产卵（例如，为越冬目的而进行），但种群同类群之间的连通性很显著。这种连通性可能会增强集合种群对峡湾内当代条件变化和转变的整体恢复力。
