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Did postglacial sea-level changes initiate the evolutionary divergence of a Tasmanian endemic raptor from its mainland relative?


Burridge, CP and Brown, WE and Wadley, J and Nankervis, DL and Olivier, L and Gardner, MG and Hull, C and Barbour, R and Austin, JJ, Did postglacial sea-level changes initiate the evolutionary divergence of a Tasmanian endemic raptor from its mainland relative?, Proceedings of the Royal Society of London: B, 280, (1773) Article 20132448. ISSN 0962-8452 (2013) [Refereed Article]

Copyright Statement

Copyright 2013 The Royal Society

DOI: doi:10.1098/rspb.2013.2448


Populations on continental islands are often distinguishable from mainland conspecifics with respect to body size, appearance, behaviour or life history, and this is often congruent with genetic patterns. It is commonly assumed that such differences developed following the complete isolation of populations by sea-level rise following the Last Glacial Maximum (LGM). However, population divergence may predate the LGM, or marine dispersal and colonization of islands may have occurred more recently; in both cases, populations may have also diverged despite ongoing gene flow. Here, we test these alternative hypotheses for the divergence between wedge-tailed eagles from mainland Australia (Aquila audax audax) and the threatened Tasmanian subspecies (Aquila audax fleayi), based on variation at 20 microsatellite loci and mtDNA. Coalescent analyses indicate that population divergence appreciably postdates the severance of terrestrial habitat continuity and occurred without any subsequent gene flow. We infer a recent colonization of Tasmania by marine dispersal and cannot discount founder effects as the cause of differences in body size and life history. We call into question the general assumption of post-LGM marine transgression as the initiator of divergence of terrestrial lineages on continental islands and adjacent mainland, and highlight the range of alternative scenarios that should be considered.

Item Details

Item Type:Refereed Article
Keywords:sea level, Last Glacial Maximum, marine dispersal, vicariance, subspecies, inbreeding depression
Research Division:Biological Sciences
Research Group:Evolutionary biology
Research Field:Biogeography and phylogeography
Objective Division:Expanding Knowledge
Objective Group:Expanding knowledge
Objective Field:Expanding knowledge in the biological sciences
UTAS Author:Burridge, CP (Associate Professor Christopher Burridge)
UTAS Author:Nankervis, DL (Miss Danielle Nankervis)
ID Code:87982
Year Published:2013
Web of Science® Times Cited:11
Deposited By:Zoology
Deposited On:2013-12-24
Last Modified:2017-11-01
Downloads:6 View Download Statistics

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