Pleistocene sea level fluctuations and the phylogeography of the dugong in Australian waters

Blair, David, McMahon, Adrian, McDonald, Brenda, Tikel, Daniela, Waycott, Michelle, and Marsh, Helene (2014) Pleistocene sea level fluctuations and the phylogeography of the dugong in Australian waters. Marine Mammal Science, 30 (1). pp. 104-121.

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Abstract

We investigated phylogeography, demography, and population connectivity of the dugong (Dugong dugon) in Australian waters using mitochondrial control region DNA sequences from 177 Australian dugongs and 11 from elsewhere. The dugong is widespread in shallow Indo-West Pacific waters suitable for growth of its main food, seagrass. We hypothesized that the loss of habitat and creation of a land barrier (the Torres Strait landbridge) during low sea level stands associated with Pleistocene glacial cycles have left a persisting genetic signature in the dugong. The landbridge was most recently flooded about 7,000 yr ago. Individual dugongs are capable of traveling long distances, suggesting an alternative hypothesis that there might now be little genetic differentiation across the dugong's Australian range. We demonstrated that Australian dugongs fall into two distinct maternal lineages and exhibit a phylogeographic pattern reflecting Pleistocene sea-level fluctuations. Within each lineage, genetic structure exists, albeit at large spatial scales. We suggest that these lineages diverged following the last emergence of the Torres Strait landbridge (ca. 115 kya) and remained geographically separated until after 7 kya when passage through Torres Strait again became possible for marine animals. Evidence for population growth in the widespread lineage, especially after the last glacial maximum, was detected.

Item ID: 31708
Item Type: Article (Research - C1)
ISSN: 1748-7692
Keywords: Australia, dugong, mitochondrial control region, phylogeography, population genetics, seagrass
Funders: Australian Research Council (ARC), Australian Fisheries Management Authority, James Cook University (JCU)
Projects and Grants: Australian Research Council-Strategic Partnerships with Industry-Research and Training grant Grant number C00002084
Date Deposited: 26 Feb 2014 09:38
FoR Codes: 06 BIOLOGICAL SCIENCES > 0604 Genetics > 060411 Population, Ecological and Evolutionary Genetics @ 30%
05 ENVIRONMENTAL SCIENCES > 0502 Environmental Science and Management > 050205 Environmental Management @ 40%
06 BIOLOGICAL SCIENCES > 0603 Evolutionary Biology > 060309 Phylogeny and Comparative Analysis @ 30%
SEO Codes: 96 ENVIRONMENT > 9608 Flora, Fauna and Biodiversity > 960802 Coastal and Estuarine Flora, Fauna and Biodiversity @ 100%
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