Importance of assessing population genetic structure before eradication of invasive species: examples form insular Norway rat populations

• Published in: Conservation Biology
• Main Authors: Abdelkrim, Jawad, Pascal, Michel, Calmet, C., Samadi, Sarah
• Other Authors: Station commune de Recherches en Ichtyophysiologie, Biodiversité et Environnement (SCRIBE), Institut National de la Recherche Agronomique (INRA), Centre National de la Recherche Scientifique (CNRS), Institut de Recherche pour le Développement (IRD), Muséum national d'Histoire naturelle (MNHN), Université Pierre et Marie Curie - Paris 6 (UPMC), Evolution Paris Seine, Université Nice Sophia Antipolis (. - 2019) (UNS), COMUE Université Côte d'Azur (2015-2019) (COMUE UCA)-COMUE Université Côte d'Azur (2015-2019) (COMUE UCA)-Centre National de la Recherche Scientifique (CNRS)-Université des Antilles et de la Guyane (UAG)-Université Pierre et Marie Curie - Paris 6 (UPMC)
• Format: Article in Journal/Newspaper
• Language: English
• Published: HAL CCSD 2005
• Subjects: assignment test; eradication unit; island; microsatellite marker; biological invasion; population structure; [SDV]Life Sciences [q-bio]; [INFO]Computer Science [cs]; Close Islands; Norway
• Online Access: https://hal.inrae.fr/hal-02683327; https://doi.org/10.1111/j.1523-1739.2005.00206.x

International audience Determining the inter-island migration abilities of pest species and delimiting eradication units enable more viable long-term eradication campaigns because recurrent colonization from neigbboring islands is avoided. We examined the genetic structure of the invasive Norway rat (Rattus norvegicus) to identify gene flow between islands and delimit population units at different geographical scales. We investigated variation in eight microsatellite loci in rat populations from 18 islands, representing five archipelagos off the Brittany coast (France). Although most of the islands are isolated from each other, short genetic distances, weak F-ST values between close islands, and a high level of cross-assignments showed that individuals collected on different islands could represent a single population unit. A Bayesian clustering method also supported the existence of big levels of gene flow between some neighboring islands. Thus, the statement "one island equals one population" can be false when inter-island distances are less than a few hundred meters. Genetic studies enable the definition of island clusters among which migration may occur that should be considered eradication units. To avoid reinvasion and to minimize ecological and economic costs, rats on all islands in an eradication unit should be eradicated simultaneously. We suggest that the genetic monitoring we performed here can be applied for management of any pest.