Population differentiation of Southern Ocean seabirds
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Date
2024
Authors
Abeyrama, Dilini Kanachana
University of Lethbridge. Faculty of Arts and Science
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Lethbridge, Alta. : University of Lethbridge, Dept. of Biological Sciences
Abstract
The Southern Ocean is a remote but unique ecosystem with high winds, strong currents, and a handful of islands surrounding the Antarctic continent. Reduced gene flow due to these physical and non-physical barriers supports rapid evolution and endemism within the Southern Ocean. Seabirds are a good model to study barrier-mediated speciation as they face a limited number of physical barriers, yet they are a highly diversified group. In my thesis, I used molecular markers to study population differentiation in five Southern Ocean seabird species at the three levels: among ocean basins, within oceans and within a single island. Sooty albatross (Phoebetria fusca) and yellow-nosed albatross showed population differentiation between Atlantic and Indian Ocean basins. Two sister species of yellow-nosed albatross, Atlantic (Thalassarche chlororhynchos) and Indian (Thalassarche carteri), both showed population genetic structure within Atlantic and Indian Oceans, respectively. The other two study species, Kerguelen shags (Phalacrocorax verrucosus) and gentoo penguins (Pygoscelis papua) breeding on Kerguelen Island, showed genetic structure among different breeding colonies of each species on the same island. Non-physical barriers such as natal philopatry and at-sea distribution, are limiting gene flow in the Southern Ocean at different geographic scales.
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Keywords
population differentiation , Southern Ocean seabirds , gene flow , barrier-mediated speciation , molecular markers