June 30, 2014
Drastic Declines Expected In Emperor Penguin Populations Over The Next Century
redOrbit Staff & Wire Reports - Your Universe Online
In less than 100 years, global warming’s impact on the sea ice where emperor penguins breed will result in the loss of at least one-fifth of the species’ population, according to new research appearing in the June 29 edition of the journal Nature Climate Change.
The study is said to be the first to analyze the long-term outlook for Antarctica’s largest type of penguin, attempting to “fill a gap” in climate change and wildlife research in one of the most distant corners of the Earth, he added. Overall, sea ice melt due to global warming is expected to result in a 19 percent decrease in emperor penguins, and two-thirds of the species’ colonies are expected to decline by at least 50 percent, the authors noted.
“For a while our model predicts that the global population size is actually going to increase but by the end of the century it’s going to have decreased significantly and it’s going to be declining quite rapidly,” co-author Hal Caswell, a biologist with Woods Hole Oceanographic Institute (WHOI) in Massachusetts, told Smithsonian writer Helen Thompson on Sunday.
Thompson explains that the fate of the emperor penguin, which is the tallest and heaviest of all living penguin species, is “inextricably linked to sea ice. It's where these iconic Antarctic birds make their home, and their trek from their nests across the ice to the ocean to hunt for food is legendary.”
If there is too much sea ice, the Smithsonian reporter explains, adult penguins have to expend too much energy finding food and spend more time feeding their young. Conversely, Suzanne Goldenberg of The Guardian points out that a lack of sea ice means there are fewer places to hide from predators, as well as a reduced supply of krill, the tiny shrimp-like crustaceans that serve as the penguins’ primary food source.
Caswell and his fellow researchers developed an algorithm that combined sea ice data with known changes to penguin populations that have occurred through breeding, development and other seasonal factors, Thompson explained. Their simulations indicate that colonies in the Ross Sea will lose the least amount of sea ice through 2050, experiencing increasing population numbers through 2100, when the decline will start to hit them as well.
Emperor penguin colonies in the eastern Weddell Sea and the western Indian Ocean will suffer the greatest losses, experiencing low sea ice and tremendous variation in sea ice levels, according to the study. The authors said that the findings are enough to justify protecting the species under the Endangered Species Act (much like the US already does for the polar bear), and they are calling for marine reserves to buffer fish stocks needed by the penguins).
“The population is declining. Unless something changes to stop that, the population will go into extinction,” Caswell told Goldenberg. He and his colleagues added that, contrary to recently published research from scientists at the University of Minnesota, the birds would not necessarily be willing to relocate in response to changing ice conditions.
He and his colleagues are now calling for several measures to be implemented in order to ensure the survival of the species. In addition to legal protections, they are advocating the establishment of a marine protected area in the Ross Sea, a move which would prohibit fishing and help make sure that the penguins have enough krill to eat. The birds could serve as an example for how to save a population from climate change-related threats before it is too late, Thompson added.