title: Dispersal in the sub-Antarctic: king penguins show remarkably little population genetic differentiation across their range.
abstract: Seabirds are important components of marine ecosystems, both as predators and as indicators of ecological change, being conspicuous and sensitive to changes in prey abundance. To determine whether fluctuations in population sizes are localised or indicative of large-scale ecosystem change, we must first understand population structure and dispersal. King penguins are long-lived seabirds that occupy a niche across the sub-Antarctic zone close to the Polar Front. Colonies have very different histories of exploitation, population recovery, and expansion.
  
  
  
  We investigated the genetic population structure and patterns of colonisation of king penguins across their current range using a dataset of 5154 unlinked, high-coverage single nucleotide polymorphisms generated via restriction site associated DNA sequencing (RADSeq). Despite breeding at a small number of discrete, geographically separate sites, we find only very slight genetic differentiation among colonies separated by thousands of kilometers of open-ocean, suggesting migration among islands and archipelagos may be common. Our results show that the South Georgia population is slightly differentiated from all other colonies and suggest that the recently founded Falkland Island colony is likely to have been established by migrants from the distant Crozet Islands rather than nearby colonies on South Georgia, possibly as a result of density-dependent processes.
  
  
  
  The observed subtle differentiation among king penguin colonies must be considered in future conservation planning and monitoring of the species, and demographic models that attempt to forecast extinction risk in response to large-scale climate change must take into account migration. It is possible that migration could buffer king penguins against some of the impacts of climate change where colonies appear panmictic, although it is unlikely to protect them completely given the widespread physical changes projected for their Southern Ocean foraging grounds. Overall, large-scale population genetic studies of marine predators across the Southern Ocean are revealing more interconnection and migration than previously supposed.
authors.affiliation: Department of Zoology, University of Oxford, South Parks Road, Oxford, OX1 3PS, UK. gemma.clucas@noc.soton.ac.uk.|Ocean & Earth Sciences, University of Southampton Waterfront Campus, European Way, Southampton, SO14 3ZH, UK. gemma.clucas@noc.soton.ac.uk.
authors.forename: Gemma V
authors.initials: GV
authors.lastname: Clucas
authors.affiliation: Department of Zoology, University of Oxford, South Parks Road, Oxford, OX1 3PS, UK. jyounger@luc.edu.|Department of Biology, Loyola University Chicago, 1032 W. Sheridan Road, Chicago, IL, 60660, USA. jyounger@luc.edu.
authors.forename: Jane L
authors.initials: JL
authors.lastname: Younger
authors.affiliation: Department of Zoology, University of Oxford, South Parks Road, Oxford, OX1 3PS, UK.
authors.forename: Damian
authors.initials: D
authors.lastname: Kao
authors.affiliation: Department of Zoology, University of Oxford, South Parks Road, Oxford, OX1 3PS, UK.
authors.forename: Alex D
authors.initials: AD
authors.lastname: Rogers
authors.affiliation: DST/NRF Centre of Excellence, Percy Fitzpatrick Institute of African Ornithology, Department of Zoology, Nelson Mandela Metropolitan University, South Campus, Port Elizabeth, 6031, South Africa.
authors.forename: Jonathan
authors.initials: J
authors.lastname: Handley
authors.affiliation: Microbiology and Immunology, PALM, University of Western Australia, Crawley, WA, 6009, Australia.
authors.forename: Gary D
authors.initials: GD
authors.lastname: Miller
authors.affiliation: Centre National de la Recherche Scientifique, Centre d'Ecologie Fonctionnelle et Evolutive, UMR 5175 du CNRS, 1919 route de Mende, F-34293, Montpellier Cedex 5, France.
authors.forename: Pierre
authors.initials: P
authors.lastname: Jouventin
authors.affiliation: Department of Biology, The Citadel, 171 Moultrie St, Charleston, SC, 29409, USA.
authors.forename: Paul
authors.initials: P
authors.lastname: Nolan
authors.affiliation: Edinburgh Genomics, Ashworth Laboratories, University of Edinburgh, Edinburgh, EH9 3JT, UK.
authors.forename: Karim
authors.initials: K
authors.lastname: Gharbi
authors.affiliation: Australian Institute of Marine Science, The UWA Oceans Institute, 35 Stirling Highway, Crawley, WA, 6009, Australia.
authors.forename: Karen J
authors.initials: KJ
authors.lastname: Miller
authors.affiliation: Department of Zoology, University of Oxford, South Parks Road, Oxford, OX1 3PS, UK.
authors.forename: Tom
authors.initials: T
authors.lastname: Hart
mesh_terms: D025041:Animal Migration / Q000502:physiology*; D000818:Animals; D000864:Antarctic Regions; D001499:Bayes Theorem; D016000:Cluster Analysis; D016002:Discriminant Analysis; D017753:Ecosystem; D014644:Genetic Variation; D005828:Genetics, Population; D060005:Genotyping Techniques; D005843:Geography; D058974:Phylogeography; D011156:Population Density; D025341:Principal Component Analysis; D046429:Spheniscidae / Q000235:genetics*
keywords: Aptenodytes patagonicus; Colonisation; Dispersal; Gene flow; Genetic homogeneity; Molecular ecology; RAD-Seq; Seabirds; Southern Ocean