When officials breached two major dams along the Elwha River, scientists immediately began studying how salmon would respond. Collectively, it was the largest dam removal in U.S. history and migratory fish including coho, Chinook and steelhead had been unable to swim the river for 100 years.
With both dams gone by 2014, salmon quickly began making their way upstream. Their return was hailed as a breakthrough for ecosystem recovery, but salmon weren’t the only species that benefited. While birds never had much difficulty making it over the dams, they had also suffered. Studies showed that less prey availability from fewer fish in the river had meant less nesting success and survivability. Fewer salmon meant fewer birds. Now scientists wondered if the birds would come back too.
To uncover bird responses to this enormous, ecosystemic change along the Elwha, Ph.D. student Ethan Duvall of Cornell University and Dr. John McLaughlin of Western Washington University are using conceptual models to forecast population shifts.
They have been looking at earlier abundance and distribution data, collected before the dams were removed, and then surveying birds along the river. Although it’s still early in the restoration process, they say, their results are encouraging. “The American dipper, for example, is now abundant in areas which they were not previously prior to dam removal,” Duvall says. Not only have the early successional species—like the spotted sandpiper—shown impressive increases in abundance, but river birds have been even more adaptable than predicted. This indicates, Duvall concludes, “that the ecosystem as a whole is responding positively to the dam removals.”