COMPOSITION AND ABOVEGROUND PRODUCTIVITY OF THREE SEASONALLY FLOODED DEPRESSIONAL FORESTED WETLANDS IN COASTAL SOUTH CAROLINA

Abstract

Depressional wetlands provide habitat for birds, mammals, reptiles, amphibians, invertebrates, and rare plant species. In order to protect, restore, and manage depressional wetlands, it is important to know more about the vegetative composition and productivity of these systems. The species composition and aboveground productivity of three seasonally flooded depressional forested wetlands were studied on the coastal plain of South Carolina from January 2000 to January 2001. The dominant tree species in the depressions were Taxodium distichum [L.] Rich., Nyssa aquatica L., and Nyssa sylvatica var. biflora [Walt.] Sarg. Annual diameter at breast height (dbh) growth was measured for all trees >10 cm dbh in five 20 × 25 m plots within each depression, and changes in dbh were used to estimate annual biomass and stem production. Aboveground net primary productivity (ANPP) was calculated for each wetland by summing stem and leaf litter production. There were no significant differences in ANPP among sites, ranging from 564–774 grams/m2/yr. These ANPP values are similar to values reported for slowly flowing forested wetland systems of the southern United States.