Emperor Penguins' Slow March Towards Extinction?

March of Penguins Turning Into Trail of Tears
By Alexis Madrigal
January 26, 2009 | 5:00:02 PM

Emperor penguin colonies will face extinction if the warming trend of the last 50 years continues over the next century.

Despite dwindling concern among Americans about climate change, the warming climate continues to change life for animals, particularly at the Earth's poles. In a new paper in the Proceedings of the National Academy of Science, biologists report that the penguins are in trouble.

"To avoid extinction, Emperor penguins will have to adapt, migrate or change the timing of their growth stages," they write. "However, given the future projected increases in [greenhouse gases] and its effect on Antarctic climate, evolution or migration seem unlikely for such long-lived species at the remote southern end of the Earth."

Across the world, it's becoming clear that some species are better than others at adapting to a changing climate. Some breed faster, making genetic changes easier. But there is a more subtle form of adaptation called phenotypic plasticity which is used to describe how animals use the genes they have to change their behavior.

For example, some species of plants can change the timing of their flowering more easily to take advantage of climate change. That's led to widespread changes in the ecosystem around Walden Pond in just the time since Henry David Thoreau prowled its shoreline, as some plants suffer and other plants benefit from the changing climate.

Like some of Walden's flowers, some bird species in Antarctica have been breeding earlier to give their chicks a chance to grow up before the sea ice breaks up. The penguins, sadly, don't appear to be so flexible.

The famously loyal and tough penguins breed miles inland through the dead of the Antarctic winter. If the sea ice on which they breed breaks up too quickly, the fluffy penguin chicks have to enter the sea before they are ready. Less sea ice also means less room for algae to grow, which in turn means fewer krill that eat the algae and ultimately less of the fish that the penguins eat. In the area the researchers studied, Terre Adelie, even 10 percent drops in the extent of sea ice reduced the population of penguins by about 50 percent.

Taking that data, the researchers modeled the Terre Adelie population with input from ten climate change scenarios developed by the Intergovernmental Panel on Climate Change. They calculated a 36 percent chance that the Emperor penguin population in the area would experience quasi-extinction, defined as a decline of more than 95 percent, by 2100.

The researchers note that the Ross Sea has experienced what climate scientists believe to be short-term sea ice gain. For now, the area will form a "last sanctuary for emperor penguin populations" but "this region too will eventually experience reduced sea ice extent as concentrations of atmospheric [greenhouse gases] increase further," they conclude.

Story courtesy of Wired Science @
http://blog.wired.com/wiredscience/2009/01/penguins.html
Image: Carlie Reum/Natio