Andersson Anastasia, Kurland Sara, Karlsson Sten, Ryman Nils, Laikre Linda
Department of Zoology Stockholm University Stockholm Sweden.
Department of Earth Sciences Natural Resources and Sustainable Development (NRHU), Uppsala University Visby Sweden.
Evol Appl. 2025 Feb 27;18(3):e70084. doi: 10.1111/eva.70084. eCollection 2025 Mar.
Translocations are carried out either unintentionally or intentionally for conservation or management reasons. In both cases, translocated populations may genetically impact natural populations via introgression. Understanding how genetic background may affect an establishment in a novel environment and the potential risks for native populations is important for biodiversity conservation. Here, using a panel of 96 SNPs, we monitor the establishment of two genetically and ecologically distinct brown trout populations released into a mountain lake system in central Sweden where trout did not occur prior to the release. The release was carried out in 1979, and we monitor the establishment over the first three decades (5-6 generations) in seven lakes downstream of the release site. We find that extensive hybridization has occurred, and genes from both populations exist in all lakes examined. Genes from the population that was nonmigratory in its native environment have remained to a higher degree in the area close to the release site, while genes from the population that was more migratory in its native habitat have spread further downstream. All established populations exhibit higher levels of genetic diversity than the released populations. Natural, stream-resident brown trout populations occur ~15 km downstream of the release site and below a waterfall that acts as an upstream migration barrier. Released fish have spread genes to these populations but with low introgression rates of 3%-8%. Recently adopted indicators for monitoring genetic diversity were partly able to detect this introgression, emphasizing the usefulness of genetic indicators in management. The SNP panel used in this study provides a similar picture as previously used allozymes, showing that older marker systems with fewer loci may still be useful for describing the population structure.
出于保护或管理目的，种群迁移可能是无意的，也可能是有意的。在这两种情况下，迁移的种群都可能通过基因渗入对自然种群产生基因影响。了解遗传背景如何影响在新环境中的定殖以及对本地种群的潜在风险，对于生物多样性保护至关重要。在这里，我们使用一组96个单核苷酸多态性（SNP），监测了两个遗传和生态上不同的褐鳟种群在瑞典中部一个山区湖泊系统中的定殖情况，该湖泊系统在放生前没有鳟鱼。放生于1979年进行，我们在放流点下游的七个湖泊中监测了最初三十年（5 - 6代）的定殖情况。我们发现发生了广泛的杂交，两个种群的基因存在于所有检测的湖泊中。来自其原生环境中不洄游的种群的基因在靠近放流点的区域保留程度更高，而来自其原生栖息地中更具洄游性的种群的基因则向下游扩散得更远。所有定殖的种群都表现出比放流种群更高水平的遗传多样性。自然的、栖息于溪流的褐鳟种群出现在放流点下游约15公里处以及一个作为上游迁移屏障的瀑布下方。放流的鱼已经将基因传播到这些种群，但基因渗入率较低，为3% - 8%。最近采用的监测遗传多样性的指标部分能够检测到这种基因渗入，强调了遗传指标在管理中的有用性。本研究中使用的SNP面板提供了与先前使用的同工酶类似的情况，表明位点较少的较旧标记系统可能仍然有助于描述种群结构。
