Human activity strongly influences genetic dynamics of the most widespread invasive plant in the sub-Antarctic



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Mairal Pisa, Mario and Chown, Steven L. and Shaw, Justine and Chala, Desalegn and Chau, John H. and Hui, Cang and Kalwij, Jesse M. and Münzbergová, Zuzana and Vuuren, Bettine Jansen van and Le Roux, Johannes J. (2021) Human activity strongly influences genetic dynamics of the most widespread invasive plant in the sub-Antarctic. Molecular ecology . pp. 1-17. ISSN 0962-1083; Electronic: 1365-294X

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The link between the successful establishment of alien species and propagule pressure is well-documented. Less known is how humans influence the post-introduction dynamics of invasive alien populations. The latter requires studying parallel invasions by the same species in habitats that are differently impacted by humans. We analysed microsatellite and genome size variation, and then compared the genetic diversity and structure of invasive Poa annua L. on two sub-Antarctic islands: human-occupied Marion Island and unoccupied Prince Edward Island. We also carried out niche modelling to map the potential distribution of the species on both islands. We found high levels of genetic diversity and evidence for extensive admixture between genetically distinct lineages of P. annua on Marion Island. By contrast, the Prince Edward Island populations showed low genetic diversity, no apparent admixture, and had smaller genomes. On both islands, high genetic diversity was apparent at human landing sites, and on Marion Island, also around human settlements, suggesting that these areas received multiple introductions and/or acted as initial introduction sites and secondary sources (bridgeheads) for invasive populations. More than 70 years of continuous human activity associated with a meteorological station on Marion Island led to a distribution of this species around human settlements and along footpaths, which facilitates ongoing gene flow among geographically separated populations. By contrast, this was not the case for Prince Edward Island, where P. annua populations showed high genetic structure. The high levels of genetic variation and admixture in P. annua facilitated by human activity, coupled with high habitat suitability on both islands, suggest that P. annua is likely to increase its distribution and abundance in the future.

Item Type:Article
Uncontrolled Keywords:Biological invasions; Dispersal; Human commensalism hypothesis; Island conservation; Polyploidy; Propagule pressure
Subjects:Medical sciences > Biology > Botany
Medical sciences > Biology > Ecology
ID Code:69685
Deposited On:20 Jan 2022 13:08
Last Modified:09 Mar 2022 12:07

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