Plant-Soil-Hydrology Relationships in Three Carolina Bays in Bladen County, North Carolina

This study provides quantitative ecological targets for restoring degraded peat-based Carolina Bays in the Carolina Flatwoods Ecoregion. Cluster analysis of vegetation data from three Carolina Bay reference sites in Bladen County, North Carolina, indicated four plant communities present: pond pine (Pinus serotina) woodland, non-riverine swamp forest dominated by swamp gum (Nyssa biflora), high pocosin dominated by evergreen shrubs with scattered pond pine, and bay forest dominated by loblolly bay (Gordonia lasianthus). We classified bay soils according to surface organic layer thickness (OLT) into mineral, histic, shallow organic, and deep organic types. We monitored the water table of each soil type in one bay throughout one growing season. The soil types with corresponding water table regimes were: mineral (9.4 cm mean OLT with a rooting zone water table [RZWT] 39% of the monitoring period), histic (27.5 cm OLT and 76% RZWT), shallow organic (63.9 cm OLT and 84% RZWT), and deep organic (102.5 cm OLT and 57% RZWT). Pearson residual analysis and correspondence analysis revealed that pond pine woodland was positively associated with mineral and histic soils, non-riverine swamp forest with shallow organic soil, bay forest with deep organic soil, and high pocosin with deep organic soil. We concluded that peat-based Carolina Bay restoration in the Carolina Flatwoods Ecoregion should be gauged against reference data which suggests: 1) pond pine woodland be established on mineral and histic soils; 2) non-riverine swamp forest be established on shallow organic soils; and 3) high pocosin and bay forest be established on deep organic soils.