Successful Projects Reclaim Wetlands
Vegetative Plantings Take Hold

WITH THE STATE LOSING LAND at the rate of a football field about every half-hour, the news about Louisiana’s wetlands is often dire.

As a means of stemming that loss and reclaiming marsh habitat, vegetative plantings offer a solid basis for hope.

“Vegetation is one of the easiest coastal restoration projects to do,” says Kenneth Bahlinger, landscape architect with the Louisiana Department of Natural Resources (DNR). “You’ve just got to get out there quick and plant.”

Revegetation may occur naturally, Bahlinger explains, but in many instances that won’t happen before tides, storms, boat wakes, and other forces of erosion wash away sediment. Hand plantings can jump-start natural vegetation growth, creating a more stable home for plants and animals.

Three recent projects— on Queen Bess Island, in the Sabine National Wildlife Refuge and at Boston Canal/Vermilion Bay— illustrate this premise and the potential plants have for holding on to Louisiana’s land.

The Greening of Queen Bess

The success of Queen Bess Island, Bahlinger says, is easy to see: “Just count the birds. That island is full of pelicans.”

Twenty years ago the brown pelican, Louisiana’s state bird, had vanished from Louisiana’s coastal wetlands as DDT pollution endangered its young and erosion claimed its habitat. Following a national ban on the use of DDT, the state reintroduced pelicans from Florida and began re-establishing their habitat. In the Barataria Bay Waterway Wetland Creation project, sediment dredged from the waterway was placed on Queen Bess Island. This small island in the Barataria-Terrebonne Estuary System had lost nearly two-thirds of its land due to storms, erosion from boat wakes, and lack of vegetation.

One factor in the pelican’s remarkable recovery — from just 675 nests in the BTES in 1990 to more than 6,500 in 2001 — was the “greening” of Queen Bess: the hand planting of two plant species. Black mangrove trees now provide nesting areas for the pelicans, while smooth cordgrass collects sediment and serves as habitat for fish and crustaceans.

“What we’ve planted there has spread and covered Queen Bess,” Bahlinger says. “Those plants are actually helping hold sediment on the island. The plants are thriving, and so are the pelicans.”

Marsh Makers

The Sabine National Wildlife Refuge — an ecotourism attraction and educational resource that draws some 300,000 visitors each year — is part of a vast ecosystem between the Calcasieu and Sabine rivers. But the construction of the Calcasieu Ship Channel in the 1960s, along with natural forces such as hurricanes, increased salinity in much of the marsh, killing its native plants and converting portions of it to open water.

To re-establish Sabine’s wetlands, one recent project (Sabine Refuge Marsh Creation, Cycle 1) created marsh from open water areas by building temporary earthen containment dikes, then filling the areas between them with material dredged from the Calcasieu Ship Channel. The perimeter of the area and the edges of trenasses— man-made bayous permitting the natural movement of water and wildlife — were planted with smooth cordgrass, which holds the sediment in place and helps create a functioning marsh as it spreads to the interior of the dredged material.

“Vegetation would probably have eventually covered the created areas naturally,” says Leigh Anne Sharp, coastal scientist with the DNR. “But hand plantings made it happen faster because it kept the soil in place.”

Four more cycles of pumping of dredged material are planned for other areas in the refuge, but results are already positive.

“The plants filled in really quickly and are beginning to create the marsh habitat,” says Sharp.“This area is ripe for restoration. The cells of marsh we’re building should help save the entire refuge.”

Reclaiming the Shoreline

For decades, wind-driven waves pounding the shoreline of Vermilion Bay and wakes from boats traveling into Boston Canal scoured away soil and plants from the fragile wetlands bordering the bay.

“Once the shoreline eroded back far enough, the open water areas within those wetlands would become part of Vermilion Bay and the interior marshland would be lost,” says Cindy Steyer, coastal vegetative specialist with the Natural Resources Conservation Service (NRCS).

As part of the 1995 Boston Canal/Vermilion Bay Shoreline Protection project, the NRCS and DNR planted 35,000 ‘Vermilion’ smooth cordgrass transplants along a 14-mile stretch of Vermilion Bay shoreline. The goal: to dissipate wave energy to reduce the rate of shoreline erosion.

Ten years later, the cordgrass has not only stabilized the shoreline, it is also collecting sediment, creating marsh that other native plants have begun to colonize naturally.

“We hoped the smooth cordgrass would just slow the rate of shoreline loss,” Steyer says. “But it has exceeded our expectations by actually promoting shoreline gain.”