title: Low genetic diversity in pygmy blue whales is due to climate-induced diversification rather than anthropogenic impacts.
abstract: Unusually low genetic diversity can be a warning of an urgent need to mitigate causative anthropogenic activities. However, current low levels of genetic diversity in a population could also be due to natural historical events, including recent evolutionary divergence, or long-term persistence at a small population size. Here, we determine whether the relatively low genetic diversity of pygmy blue whales (Balaenoptera musculus brevicauda) in Australia is due to natural causes or overexploitation. We apply recently developed analytical approaches in the largest genetic dataset ever compiled to study blue whales (297 samples collected after whaling and representing lineages from Australia, Antarctica and Chile). We find that low levels of genetic diversity in Australia are due to a natural founder event from Antarctic blue whales (Balaenoptera musculus intermedia) that occurred around the Last Glacial Maximum, followed by evolutionary divergence. Historical climate change has therefore driven the evolution of blue whales into genetically, phenotypically and behaviourally distinct lineages that will likely be influenced by future climate change.
authors.affiliation: School of Biological Sciences, Flinders University, GPO Box 2100, Adelaide, South Australia 5001, Australia Department of Biological Sciences, Macquarie University, Sydney, New South Wales 2109, Australia catherine.r.attard@gmail.com.
authors.forename: Catherine R M
authors.initials: CR
authors.lastname: Attard
authors.affiliation: School of Biological Sciences, Flinders University, GPO Box 2100, Adelaide, South Australia 5001, Australia.
authors.forename: Luciano B
authors.initials: LB
authors.lastname: Beheregaray
authors.affiliation: Centre for Whale Research, PO Box 1622, Fremantle, Western Australia 6959, Australia.
authors.forename: K Curt S
authors.initials: KC
authors.lastname: Jenner
authors.affiliation: Blue Whale Study, C/- Post Office, Narrawong, Victoria 3285, Australia School of Life and Environmental Sciences, Deakin University, PO Box 423, Warrnambool, Victoria 3280, Australia.
authors.forename: Peter C
authors.initials: PC
authors.lastname: Gill
authors.affiliation: Centre for Whale Research, PO Box 1622, Fremantle, Western Australia 6959, Australia.
authors.forename: Micheline-Nicole M
authors.initials: MN
authors.lastname: Jenner
authors.affiliation: School of Life and Environmental Sciences, Deakin University, PO Box 423, Warrnambool, Victoria 3280, Australia.
authors.forename: Margaret G
authors.initials: MG
authors.lastname: Morrice
authors.affiliation: School of Biological Sciences, Flinders University, GPO Box 2100, Adelaide, South Australia 5001, Australia Molecular Zoology Laboratory (Aquatic Division), Department of Zoology, University of Johannesburg, Auckland Park 2006, South Africa.
authors.forename: Peter R
authors.initials: PR
authors.lastname: Teske
authors.affiliation: School of Biological Sciences, Flinders University, GPO Box 2100, Adelaide, South Australia 5001, Australia.
authors.forename: Luciana M
authors.initials: LM
authors.lastname: Möller
mesh_terms: D000818:Animals; D001315:Australia; D050616:Balaenoptera / Q000235:genetics*; D002980:Climate; D003247:Conservation of Natural Resources; D018703:Founder Effect; D014644:Genetic Variation; D011156:Population Density
keywords: Australia; Balaenoptera musculus; climate change; endangered species; phylogeography; speciation