Saturday, August 9, 2014

SBU's Lynch ruffles feathers with penguin population study

By Daniel Dunaief

An Adelie penguin with her young. Photo by Philip McDowall

August 08, 2014 | 11:53 AM
Calling them as she sees them has stirred up some trouble for Heather Lynch. An ecologist at Stony Brook, Lynch recently shared her estimate of the global population of the Adelie penguin, which waddles, feeds, and raises its young in the Antarctic.

The Adelie - pronounced ah deli - are considerably more numerous than previous estimates. Considered an indicator of climate change in the Antarctic because they respond to local conditions around the colony, the two and a half foot flightless water fowl number about 3.79 million breeding pairs, which is 53% higher than earlier figures.

"The losses" in some penguin populations "are more than offset by the gains we're picking up on the continental part," Lynch said.

Lynch has received some frustrated emails from conservationists that suggest the results may not be consistent with the messages they are sending.


Heather Lynch at Spigot Peak on the Antarctic Peninsula. Photo by Catherine Foley
"Our willingness to report on these findings makes some conservationists uncomfortable because there is a tendency in the media and with readers to conflate population gains with a rejection of climate change, or even as a benefit of climate change," she said. The evidence, and the use of that information, doesn't invalidate the notion of global warming or make the penguin, an animated hero in movies and an attraction to families at the Central Park Zoo, any less important or worth studying.

"Climate change is occurring in Antarctica: the shifts we have documented in the Adelie populations speaks to the ecological changes now under way due to climate change," she said.

Looking closely at the numbers, Lynch said the population of this type of penguin, which has a white ring around the eye, long black tail and white chest that gives the bird its tuxedo appearance, has decreased on the Antarctic peninsula, amid a reduction in the population of one of their primary food sources, krill, in the Western Antarctic Peninsula. Those declines, however, have been more than counterbalanced by greater penguin population on the continent, where these birds may have found more places to breed and where there has been a decline in the toothfish, a competitor that also eats krill.

Lynch said the study of the Adelie penguins is a "complex story" and will require further study to identify the causes of these changes.

Indeed, Lynch and her collaborator on the penguin population project, Michelle LaRue, a research associate at the University of Minnesota in the Earth Sciences Department, surveyed these birds to provide information that might help policy makers with fisheries management. They didn't intend their study to ruffle feathers in the conservation community.

"Pinning down the distribution [of Adelie penguins] is one piece of a larger puzzle to determine sustainable krill catch limits," Lynch said. LaRue and Lynch spent about 10 months pouring over satellite images. The satellites were not able to pick up the image of these waddling birds, but they were able to provide a map of their guano, or droppings. The color of their droppings is usually reddish.

Above, an aerial view of a penguin colony on Paulet Island. The reddish stains are penguin poop, or guano, which Heather Lynch uses to count the penguin population. Photo by Ron Naveen

Since this was the first time researchers used satellite images, the comparison to earlier data, providing the 53% increase, creates some room for interpretation."We were using published information," said LaRue, which included "the information on hand at the time," but didn't tap into the views afforded by satellite images.

Indeed, Lynch and LaRue plan to revisit this number in about five years, using the same method to compare the change in the number of penguins.

"We could have caught them on a high year," LaRue said. "The next time, it could be lower or vice versa. This represents a base line from which we can make better and more accurate management decisions and learn about the species."

Lynch and LaRue have collaborated for close to four years. Lynch is a "brilliant quantitative ecologist," LaRue said. "When you're in the field, you go, go, go."

After a full day of trudging through three feet of snow to collect information about penguins, Lynch took more pictures of the colonies all the way up until the last call to return to the ship, LaRue described.

Lynch said she sees her role as providing data regardless of the result. "I want to be the trusted umpire," she said. "I limit my comments to what the data are telling us." At this point, she said, the data are telling her what is happening. The next step is to figure out why.

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