The wetland vegetation of Caddo Lake

Caddo Lake, located along the boundary of northeastern Texas and northwestern Louisiana, contains extensive areas of relatively undisturbed forested wetlands and has been designated a wetland of international importance under the Ramsar Convention. Vegetation and water levels from 30 plots were sampled. Aerial photographs of the 3000 ha Caddo Lake State Park and Wildlife Management Area were used to map the park into 119 survey areas, each representing a distinct patch of vegetation. Both data sets were separately subject to Two Way Indicator Species Analysis (TWINSPAN) classification and Detrended Correspondence Analysis (DCA) ordination. Water levels were strongly correlated with the first axis of a DCA ordination of the 30 plots which arranged plots along a flooding gradient from mesic natural levees and terraces to cypress swamps. These results were corroborated by analysis of data from the 119 survey areas and were used to identify six community types: Rich Mesic Slopes, Mesic Bottomland Ridges, Bottomland Oak Flats, Cypress-Water elm Swamps, Closed-Canopy Cypress Swamps and Deep water Cypress Swamps. These communities are comparable to other wetland communities described for the region.