Hydrology and Vegetation Relationships in a Carolina Bay Wetland 15 Years after Restoration.

Restoring wetlands is expensive, and hydrology criteria are needed to determine if restored sites are saturated long enough to support the planted vegetation. This study determined relationships among hydrology, soils, and vegetation in a restored Carolina Bay wetland (CBW) to identify field indicators of saturation duration. The study site was in Robeson County, NC in a CBW that had been restored for 15 years. Water-table data for the five-year period following restoration were used to establish saturation periods of: ≤13, 14-50, 51-100, and 101-225 consecutive days occurring during the growing season and within 30 cm of the surface. Sampling plots were established 15 years after restoration along a hydrologic gradient to identify vegetation type, tree basal area, tree height, wetland hydrology field indicators, and inundation. The number of hydrology field indicators increased 50%, going from ≤13 to 101-225 days of saturation. Dominant tree species at the restored site were similar to those found in three reference CBWs. Where saturation occurred for 101+ days, tree basal area and height decreased 40-69% compared to where saturation periods were shorter. Areas that experienced saturation for <51 days contained trees that were 10 cm larger in diameter, had more shrubs and vines, and contained less areal cover of graminoids compared to areas that had saturation for 101- 225 days. Regression equations predicted average saturation duration during the growing season using number of hydrologic field indicators and tree height with R² values between 0.62 and 0.73. Such relationships would be useful to evaluate restoration success. [ABSTRACT FROM AUTHOR]