Research: Climate change good for Arctic geese

zhollander@adn.comJanuary 21, 2014 

A warmer Arctic isn't all bad news.

Newly published research indicates that climate change has created new, high-quality plants to feed Alaska's most northern geese.

Tens of thousands of black brant geese now flock to the Arctic coast to munch marsh-loving vegetation growing along shorelines of thawed permafrost no longer safeguarded from saltwater storm surges by sea ice, according to new U.S. Geological Survey research announced Tuesday.

The research centered on black brants during their molting season when they lose and regrow feathers, but also reflects similar changes for Canada geese, snow geese and greater white-fronted geese.

Scientists conducting surveys in new molting areas say they found 10,000 more black brant around the Cape Simpson area southeast of Barrow -- a 50 percent increase in a population previously estimated at about 20,000. The discovery of more birds in new places led the Bureau of Land Management last year to expand an existing oil and gas closure in the Teshekpuk Lake Special Area, part of the National Petroleum Reserve-Alaska.

The good news for geese marks a rare positive in Arctic research known more for negatives such as the potentially disastrous effect climate change and related sea ice loss are having on ice-dependent northern animals like walrus and polar bear. The Arctic has heated up twice as fast as the rest of the planet in the past three decades.

Researchers from USGS and the University of Alaska Fairbanks say climate change will create winners along with losers as big, landscape-level shifts filter down to different animals and places.

"In the context of the geese, this is a winner for them," said Paul Flint, a USGS research wildlife biologist with the Alaska Science Center. "Sea ice completely goes away -- that's a lose type of thing."

The research about why the birds moved their molting grounds is new, but the Arctic geese migration actually started decades ago.

Back in the 1970s, the U.S. Fish and Wildlife Service noted a shift in the distribution of black brant geese near Teshekpuk Lake, a large inland body of water southeast of Barrow in the center of the Arctic coastal plain. Black brant and other geese shifted in large numbers from large inland lakes like Teshekpuk to coastal salt marshes during the molting season. Birds that are molting can't fly. They need food close by and water to dive into for protection from predators.

The tundra that stretches like a golf green along the Beaufort Sea offers all that, researchers say.

A "surreal" former radar site known as Lonely Point became the center for field work as scientists worked to better understand why the geese moved their molting grounds, said Ken Tape, a terrestrial ecologist with UAF's Institute of Northern Engineering.

The abandoned Distant Early Warning line site sits about a third of the way along the coast from Barrow to Prudhoe Bay. Along with tent camps, researchers set up shop in an abandoned control tower at the mile-long runway at the site. They'd spot waves of caribou fleeing inland mosquitoes along the breezy coastline, Tape said.

The area is renowned for its high concentration of molting birds, said Flint, estimating that some 100,000 geese of all four species spent time in that area over the last several years in a patchy strip along the ocean extending as much as a mile or two inland.

Researchers studied the birds, of course. But they also dug pits into the peaty dirt to see what used to grow in the area -- freshwater grasses and water-loving, grass-like sedges later replaced by sedges only. Tape examined historic photos of the area dating back to 1948.

Today, the area is marshier but Tape said he's not sure whether thawed permafrost caused the shore level to drop or higher water from storm surges caused the sea to rise.

Regardless, formerly dry uplands are now carpeted with low sedges that provide the high-protein, low-fiber diet that geese crave, Flint said. Researchers conducting all kinds of studies -- shade houses to cool down the cover, greenhouses to warm it -- discovered the nutrient quality of the plants only get better as climate change continues, he said.

That said, it's also possible that continued coastal erosion could devour all that tasty goose forage, though many of the birds' favorite spots are located in more protected areas off the more vulnerable bluffs.

"It's a bit of an arms race," Flint said. "Habitat conversion is extending inland as permafrost degrades, but we're also getting some erosion along the beaches. It's going to take some time to find out who's winning the race."

Researchers also found that the geese didn't decamp from Teshekpuk because they went hungry, Flint said. Studies showed the inland geese are in better shape now than they used to be.

The research is part of a larger, USGS-led program called the Changing Arctic Ecosystems initiative.

Tape said he hope to release more large-scale Arctic findings within the next six months or so.

The findings by USGS, UAF and the U.S. Fish and Wildlife Service were published this month by the journal Environmental Research Letters and will be published by the Journal of Field Ornithology in March.

Reach Zaz Hollander at zhollander@adn.com or 257-4317.

 

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