Research Found That Earlier Spring Geese Migration Does Not Impact Arctic Vegetation Quality

Apr 23, 2019

Black brants migrate north to western Alaska to breed, grazing on nutritious vegetation.
Credit Doug Wechsler/National Audubon Society

Scientists have found that climate change impacts the timing of early spring vegetation growth and bird migration. New research investigates if earlier bird migration to the Arctic results in lower quality vegetation.   

"With climate change, what we’re seeing is that the timing of events is changing and in the Arctic in particular - where it is warming faster than it is warming in temperate areas - we’re seeing a lot of events are changing their timing and one big thing that is happening is that springs are coming earlier," said Karen Beard, a professor in wildland resources at Utah State University.

Beard and her collaborators work in the Yukon-Kuskokwim Delta on the coast of western Alaska.

"And it is a really large wetland so the landscape has a lot of rivers and lakes and a lot of water, and the vegetation is mostly short-stature sedges and grasses and small forbs," Beard said. 

The vegetation in this delta is the perfect nutrition for migratory Arctic geese like the black brant. But the timing of vegetation growth and the timing of geese arrival is changing. Beard investigated whether or not earlier migration impacts grass forage quality for the black brant.

"So birds migrate up to the Arctic to breed and to nest and to have their young then they fly south, and so their young need to have vegetation that is really high in nutrients and high in resources for them," Beard said.

During her experiment, Beard manipulated spring arrival through warming chambers and manipulated when the black brant arrive in the delta.

"Even though we advanced spring about weeks in terms of vegetation height, we found that forage quality was not significantly impacted by that," Beard said. "So while we were working under the assumption that if spring starts earlier, then geese are going to get lower quality forage. We didn’t find that in our experiment - the forage quality was not different."

Beard found that earlier geese arrival means more nutritious forage because the protein content in the grass increases with the geese’s arrival. According to Beard, this research is just the beginning of understanding climate change impacts in complex and connected ecosystems.