Too much of a good thing: sea ice extent may have forced emperor penguins into refugia during the last glacial maximum.
The relationship between population structure and demographic history is critical to understanding microevolution and for predicting the resilience of species to environmental change. Using mitochondrial DNA from extant colonies and radiocarbon-dated subfossils, we present the first microevolutionary analysis of emperor penguins (Aptenodytes forsteri) and show their population trends throughout the last glacial maximum (LGM, 19.5-16 kya) and during the subsequent period of warming and sea ice retreat. We found evidence for three mitochondrial clades within emperor penguins, suggesting that they were isolated within three glacial refugia during the LGM. One of these clades has remained largely isolated within the Ross Sea, while the two other clades have intermixed around the coast of Antarctica from Adélie Land to the Weddell Sea. The differentiation of the Ross Sea population has been preserved despite rapid population growth and opportunities for migration. Low effective population sizes during the LGM, followed by a rapid expansion around the beginning of the Holocene, suggest that an optimum set of sea ice conditions exist for emperor penguins, corresponding to available foraging area.
Institute for Marine and Antarctic Studies, University of Tasmania, Private Bag 129, Hobart, 7001, Tas., Australia; Australian School of Advanced Medicine, Macquarie University, 2 Technology Place, Sydney, 2109, NSW, Australia.
Jane L
JL
Younger
Gemma V
GV
Clucas
Gerald
G
Kooyman
Barbara
B
Wienecke
Alex D
AD
Rogers
Philip N
PN
Trathan
Tom
T
Hart
Karen J
KJ
Miller
D000818:Animals; D000864:Antarctic Regions; D005075:Biological Evolution; D057231:Climate Change; D004272:DNA, Mitochondrial; D005580:Fossils; D046448:Ice Cover; D058974:Phylogeography; D011156:Population Density; D000068236:Refugium; D046429:Spheniscidae / Q000235:genetics* / Q000502:physiology
D004272:DNA, Mitochondrial
Antarctica; Aptenodytes forsteri; Ross Sea; climate change ecology; molecular ecology; paleoecology; phylogeography; polynya