"There may be more breeding habitat available now, but there may not be enough food available to sustain those penguin populations which are declining, especially in the Antarctic Peninsula where the warming is the most severe," said co-author Michael Polito, a WHOI post-doctoral investigator.
In contrast, gentoo penguin populations continue to grow. Gentoo penguins forage on a variety of prey. Scientists believe this species may be able to better adapt to shortages in krill, because of their flexible diet.
"What we are seeing is a 'reversal of fortunes' where increased warming is no longer good for two out of the three species of Antarctic Peninsula penguins. This research shows quite clearly how a single environmental change, in this case warming, can have different consequences over time," said Polito.
The scientists collected feather and blood samples from 537 modern penguins in colonies around the Antarctic Peninsula and sequenced the penguins' DNA from these samples. By calculating the rate of mutation, they were able to chart how these populations varied over time in order to result in the genetic diversity and population size exhibited today.
"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," said co-author Tom Hart of the University of Oxford's Department of Zoology.'/>"/>
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Woods Hole Oceanographic Institution