Quite unexpectedly, the shrinking glaciers cause Adélie penguin population explosion in East Antarctica. Unlike other species of penguins, they are apparently adapting well to the environmental effects of global warming, says a new study.
In the study published in BioMed Central Evolutionary Biology, researchers found that in the last 14,000 years, the population of Adélie penguins increased as new breeding sites and ice-free grounds emerged due to shrinking glaciers.
Around 30 percent of the global population of this species is found in the region of East Antarctica. Overall, there is an estimated 1.14 million breeding pairs.
To land to their findings, they used mitochondrial DNA from colonies around 22,000 years ago. They recreated the population drift of Adélie penguins in East Antarctica by using an extended Bayesian skyline plot method.
They found that deglaciation appears to be the factor that affected the increase of population among Adélie penguins rather than changes in sea conditions. They recommend the use of millennial-scale trends with contemporary data to predict trends in population of species that might happen in future climate change occurrence.
"Mitochondrial DNA sequence data has revealed that Adélie penguin numbers in East Antarctica increased 135-fold during the most recent glacial-interglacial transition. This dramatic expansion suggests that the East Antarctic environment is currently much more favourable for Adélie penguins," the study discussed.
The findings show that during the ice age, there were lesser Adélie penguins than emperor penguins. This is because their nesting sites and feeding grounds were all covered with ice. However, as the ice age ends, temperatures slowly increased and by 10,000 years ago, annual declines in glaciers were reported.
"This is an important finding, as it suggests that the effects of climate change on a species over thousands of years can be quite different to the effects over years or decades," said lead author Jane Younger from the University of Tasmania, Australia.
As climate change progresses, more glaciers will shrink. Though this scenario is conducive to nesting among these penguins, there should be sufficient food supplies to meet the demand of a growing population.
"Adequate food supplies must be available to sustain an expanding population of Adélie penguins. Whether this will be the case in the future remains to be seen, as the impacts of climate change on Adélie penguin prey species, such as Antarctic krill, are unclear at this time," Younger added.
Photo: Lin Padgham | Flickr
