July 2, 2008
Penguins Suffering Greatly From Climate Change
A new study shows that penguin populations are dwindling at a key breeding colony in Argentina, mirroring declines in many other species of the flightless birds, due to climate change and pollution.
P. Dee Boersma, a biologist at the University of Washington, detailed specific problems around the world with remote penguin populations, linking their decline to the overall health of southern oceans.
"Now we're seeing effects (of human caused warming and pollution) in the most faraway places in the world," said Boersma.
"Many penguins we thought would be safe because they are not that close to people. And that's not true."
She has tracked the world's largest breeding colony of Magellanic penguins located at Punta Tombo on Argentina's Atlantic coast for the last 25 years. Since 1987 she has observed a 22 percent decrease in the population of these penguins at the site.
Boersma said the decline appears to have begun in the early 1980s after the population at the site peaked probably at about 400,000 breeding pairs of Magellanic penguins between the late 1960s and mid-1970s. Today's total is half of that.
The International Union for the Conservation of Nature lists three penguin species as endangered, seven as vulnerable, which means they are "facing a high risk of extinction in the wild," and two more as "near threatened." About 15 years ago only five to seven penguin species were considered vulnerable, experts said.
The decline overall isn't caused by one factor, but several.
The world's warming climate is only one of the causes of the penguins' problems. They also are threatened by oil pollution, depletion of fisheries, becoming entangled in fishing nets, and coastal development that eliminates breeding habitats, according to Boersma.
"Penguins are in trouble," said Boersma. "They certainly are canaries in the coal mine."
"Global warming in the western Antarctica peninsula is a problem for the ice-loving Adelie penguins, making it harder for them to find food," said Phil Trathan, head of conservation biology at the British Antarctic Survey, a top penguin scientist who had no role in the new report.
Boersma said for penguins that live on the Galapagos Island, El Nino weather patterns are a problem because the warmer water makes penguins travel farther for food, at times abandoning their chicks. At the end of the 1998 record El Nino, female penguins were only 80 percent of their normal body weight. Scientists have tied climate change to stronger El Ninos.
She said oil spills off Uruguay, Argentina and Brazil have tainted the water penguins live off of and have contributed to the Punta Tumbo declines.
"The findings illustrate the disruption that people have caused to penguins' ecosystems," said Anton Seimon of the Wildlife Conservation Society, which backed Boersma's work.
"What happens to penguins, a few years down the road can happen to a lot of other species and possibly humans," said longtime penguin expert Susie Ellis, now executive director of the International Rhino Foundation.
The study is published in the July edition of the journal Bioscience.