Role of Introduction History and Landscape in the Range Expansion of Brown Trout (Salmo trutta L.) in the Kerguelen Islands

• Published in: Journal of Heredity
• Main Authors: Launey, Sophie, Brunet, Géraldine, Guyomard, René, R., Davaine, Patrick
• Other Authors: Unité de recherche Génétique des Poissons (UGP), Institut National de la Recherche Agronomique (INRA), Écologie et santé des écosystèmes (ESE), Institut National de la Recherche Agronomique (INRA)-AGROCAMPUS OUEST, Ecologie Comportementale et Biologie des Populations de Poissons (ECOBIOP), Institut National de la Recherche Agronomique (INRA)-Université de Pau et des Pays de l'Adour (UPPA)
• Format: Article in Journal/Newspaper
• Language: English
• Published: HAL CCSD 2010
• Subjects: adaptation; environmental factor; genetic variability; landscape; migration; salmo trutta; [SDV]Life Sciences [q-bio]; Kerguelen Islands
• Online Access: https://hal.inrae.fr/hal-02655643; https://doi.org/10.1093/jhered/esp130

International audience Human-mediated biological invasions constitute interesting case studies to understand evolutionary processes, including the role of founder effects. Population expansion of newly introduced species can be highly dependant on barriers caused by landscape features, but identifying these barriers and their impact on genetic structure is a relatively recent concern in population genetics and ecology. Salmonid populations of the Kerguelen Islands archipelago are a favorable model system to address these questions as these populations are characterized by a simple history of introduction, little or no anthropogenic influence, and demographic monitoring since the first introductions. We analyzed genetic variation at 10 microsatellite loci in 19 populations of brown trout (Salmo trutta L.) in the Courbet Peninsula (Kerguelen Islands), where the species, introduced in 3 rivers only, has colonized the whole water system in 40 years. Despite a limited numbers of introductions, trout populations have maintained a genetic diversity comparable with what is found in hatchery or wild populations in Europe, but they are genetically structured. The main factor explaining the observed patterns of genetic diversity is the history of introductions, with each introduced population acting as a source for colonization of nearby rivers. Correlations between environmental and genetic parameters show that within each "source population" group, landscape characteristics (type of coast, accessibility of river mouth, distances between rivers, river length .) play a role in shaping directions and rates of migration, and thus the genetic structure of the colonizing populations.