While penguins have adapted to extremely cold weather, harsh winters are still difficult for populations especially when it comes to breeding and finding food. So with warming climates on the horizon, are penguin populations going to be better off? Not necessarily. However, a new study does reveal that penguin populations over the last 30,000 years have benefitted in some ways from climate warming and retreating ice.
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An international team, led by scientists from the University of Southampton and Oxford University, has used a genetic technique to estimate when current genetic diversity arose in penguins and to recreate past population sizes.
Looking at the 30,000 years before human activity impacted the climate, as Antarctica gradually warmed, they found that three species of penguin; Chinstrap, Adélie and southern populations of Gentoo penguins increased in numbers. In contrast, Gentoo penguins on the Falkland Islands were relatively stable, as they were not affected by large changes in ice extent.
‘Whereas we typically think of penguins as relying on ice, this research shows that during the last ice age there was probably too much ice around Antarctica to support the large populations we see today,’ said lead author Gemma Clucas Ocean and Earth Sciences at the University of Southampton. ‘The penguins we studied need ice-free ground to breed on, and they need to be able to access the ocean to feed. The extensive ice-sheets and sea ice around Antarctica would have made it inhospitable for them.
‘What is particularly interesting is that after the ice age, all of these penguin populations were climate change ‘winners’, that is to say the warming climate allowed them to expand and increase in number. However, this is not the pattern we’re seeing today. Adélie and Chinstrap penguins appear to be declining due to climate change around the Antarctic Peninsula, so they’ve become ‘losers’. Only the Gentoo penguin has continued to be a ‘winner’ and is expanding its range southward.’
Dr Tom Hart of Oxford University’s Department of Zoology, an author of the paper, said: ‘We are not saying that today’s warming climate is good for penguins, in fact the current decline of some penguin species suggests that the warming climate has gone too far for most penguins.
‘What we have found is that over the last 30,000 years different penguin species have responded very differently to a gradually warming world, not something we might expect given the damage current rapid warming seems to be doing to penguins’ prospects.’
Continue reading at the University of Oxford.
Chinstrap penguin image via Shutterstock.