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Go DeeperThe Nature Conservancy in Oregon Explosives Aid Wetland Restoration in Klamath Basin The Conservnacy's Global Freshwater Team |
Bringing Back the Salad Bar
One of the biggest drivers of wetland losses has been farming. Some of the most intensively farmed land in the country is in the Mississippi River drainage, and losses there have been staggering: 85 percent in Illinois; 87 percent in Indiana and Missouri; 89 percent in Iowa; and 90 percent in Ohio.
As at Upper Klamath Lake in Oregon, much of the historic floodplain of the Mississippi River Basin has been converted to farmland after more than 3,400 miles of federal levees and thousands of miles of private levees were built to contain the Mississippi and its tributaries.
Now the Conservancy is working to restore wetlands in the river’s floodplain. In 1997 the Conservancy bought out a 2,000-acre levee district—a low-lying tract of land separated from the river by dikes—on the Illinois River, a tributary of the Mississippi. The area, now known as Spunky Bottoms, served as ground zero for a number of wetland-restoration test runs. Their success led the Conservancy in 2000 to purchase a 9,300-acre levee district just upstream, where the river makes a lazy bend at a place called Emiquon. That deal stands as the largest private conservation land purchase in Illinois history.
Michael Reuter, the Conservancy’s conservation programs director for the central U.S. region, says that Emiquon “was a legendary place” with a rich history of use by the Illinois Indians and by birds using the Mississippi Flyway. It has also proved to be the ideal place to further experiment with wetland-restoration techniques that the Conservancy plans later to apply on a much wider scale.
Wide-scale restoration along the Mississippi and its tributaries could increase habitat for fish, migratory waterfowl and other wildlife such as river otters. And by increasing opportunities for aquatic plants to take up the river’s notoriously high concentrations of agricultural fertilizers, it could also help fight the “dead zone” in the Gulf of Mexico, where tons of nitrogen and other nutrients washing off Midwestern farms have turbocharged algae growth and suffocated fish.
There is no set playbook for wetland restoration. Both environmental groups and government agencies are, to a large extent, writing the book as they go. But the Conservancy has an important advantage. “The state and federal agencies aren’t able to take as many risks as a private organization like The Nature Conservancy,” says Reuter. “What we really needed was to buy a place and be willing to be embarrassed.”
He adds, “We’ve been dealt some pretty serious lessons about how challenging this is.” Simply removing the levee, Klamath-style, would have allowed the river’s fluctuating levels to pump plant-smothering sediment into the restored wetlands—and left them exposed to invasive species such as silver, bighead and grass carp. Instead, the Conservancy left the levee in place, and the Army Corps is now designing a $2 million to $3 million gated structure that will control the flow of water and let fish in and out.
But simply designing the water-control structure has been a lesson in the slippery challenges of re-engineering heavily manipulated systems for environmental sustainability. Doug Blodgett, the Conservancy’s Illinois River program director, says the restored wetlands could provide important habitat for paddlefish—sturgeonlike fish with noses that look like outsized shoehorns. But “that snout is filled with electro-receptors,” Blodgett says, “and it turns out they’ll avoid metal.”
Water-control structures are traditionally built of steel; at Emiquon, the Conservancy will have to use concrete- or plastic-encased gates instead. Other fish won’t swim into dark openings, so the Conservancy will have to add grating over the top of the control structure to allow sunlight to penetrate into the fish passageway.
The control-structure design will likely be finalized next year. In the meantime, Blodgett’s team is replanting native hardwoods such as swamp white oak, pin oak, shellbark hickory, sycamore and pecan. The Conservancy has also begun returning water to the diked-off area so that wetland plants can grow again on what were formerly corn and soybean fields. In the process, Blodgett has discovered that the formula for reviving wetland plants is the simplest part of the entire restoration. In fact, it’s about as simple as growing a package of Sea Monkeys: Just add water.
“Wetlands are phenomenally resilient,” says Blodgett. “Some wetland seeds can lie dormant for a century, and they’re still viable.” At the Conservancy’s Spunky Bottoms preserve, Blodgett says he’s seen the plants come back on their own, “even from a seed bank that was lying dormant with agriculture and pesticides for 80 years.”
For birds such as mallards, pintails, gadwalls, widgeons and teal, Blodgett says, “it’ll be a big salad bar out there.”
Nature picture credits: Illustration © Alan Daniels
