A makeover turns manmade Aramburu Island into rich wildlife habitat.
A 20-ton loader is tearing up the east shore of California's Aramburu Island, knocking down a seven-foot scarp to make way for an oyster shell beach. Farther north, heavy equipment is scouring the island's marshes and mudflats, replacing the barren soil with bay sands to attract native invertebrates.
What may look like devastation is a $2.4-million restoration of the 36-acre island in Richardson Bay, a slender arm of San Francisco Bay that is managed as a sanctuary by Audubon California. The project is part of a multi-agency effort to bring back the habitat of the entire San Francisco Bay, the most important estuary on the Pacific Coast of the Americas. By the time Aramburu's two-year restoration is complete in March 2013, it will offer seasonal saline wetlands for whimbrels and marbled godwits, and smooth beaches where sandpipers can forage and harbor seals can rest.
Thirty-six acres of tidal marshes and subtidal mudflats may not seem like much, but in a region that has lost 90 percent of its wetlands in the past century, it's huge, says Brooke Langston, director of Audubon's Richardson Bay Center and Sanctuary, the project coordinator. "We have so few chances to bring back the bay habitat," she says. "Healthy mudflats and sandy beaches are just gone--until now."
Aramburu Island, owned by Marin County, was made in the 1950s and 1960s from navigational spoils and debris dumped into Richardson Bay from hillsides excavated for development. Its rocky shores and weedy banks were largely ignored by birds and birders until November 2007, when 58,000 gallons of oil spilled into San Francisco Bay (see "Bay Watch," November-December 2008). Two months later nearly two million gallons of sewage sloshed into Richardson Bay, followed by an outbreak of avian cholera.
That triple-whammy winter put Aramburu in the spotting scope. Hundreds of stressed grebes, scaups, and scoters sought refuge there, a safe haven from polluted bay waters. Surprised by the concentration and variety of birds, Langston and her staff began imagining what the island might offer if it were healthy habitat. By the time spill reparation funds began rolling in, they had a plan: Import local bay soil and plant it with pickleweed and other natives to invite terns, plovers, and more. Along with improved habitat, they designed the remake to reduce erosion and increase resilience to rising sea levels.
As crews began taking sediment samples to compare the invertebrate content pre- and post-construction, Aramburu bestowed another surprise: new and healthy colonies of native oysters--hundreds of them growing on rocks in the mud just offshore. For Audubon and its partners around San Francisco Bay, they are the promise of Aramburu's future.