PARENT SESSION
Poster Session #21: Riparian and Wetland Restoration.
Tuesday, August 6. Presentation from 5:00 PM to 6:30 PM. Exhibit Hall B & C, TCC

Experimental restoration of Southeastern Coastal Plain depression wetlands.

DE STEVEN, DIANE^*,1, SHARITZ, REBECCA², SINGER, JULIAN¹, ¹ USDA FOREST SERVICE, CHARLESTON, SC² SAVANNAH RIVER ECOLOGY LABORATORY, AIKEN, SC

ABSTRACT- Many Coastal Plain depression wetlands were historically altered by ditching and draining. Their role as unique habitats for biodiversity has focused interest on their restoration. In 2001 a landscape-scale experiment was initiated to test whether these restorations can proceed by "self-design" or whether planting and additional management facilitate success. In sixteen formerly-disturbed depressions on the forested Savannah River Site, South Carolina, pre-restoration vegetation consisted of facultative tree species and sparse understory plant cover. Ditches were plugged to restore hydrologies, and forest canopy was harvested to open the sites for wetland vegetation development. For eight depressions with herbaceous wetland as the restoration objective, remnant seedbanks were planned as the principal means of revegetation. The remaining depressions were planted with wetland tree saplings to promote forested wetland. We sampled pre-restoration ground-layer and seedbank composition and measured initial post-restoration vegetation response. Seedbanks had low similarity to pre-restoration ground cover. Germination from the seedbank was promoted by soil scarification during timber harvest. Herbaceous cover increased but was dominated by short-lived, largely facultative species from the seedbanks. Typical wetland dominants such as clonal grasses were generally absent in the seedbanks and the initial vegetation. Experimental planting of grasses appears initially successful and may accelerate recovery. However, a regional drought has hindered initial success of hydrologic restoration and may encourage establishment of weedy species from the surrounding managed uplands. Unpredictable environments may slow recovery by self-design.

KEY WORDS: wetland restoration, restoration ecology, isolated depression wetlands