Vegetation and environmental factors of inland saline wetlands in the upper St. Johns River Basin, Florida, U.S.A.

Inland saline wetlands are a global ecosystem that rarely occur in humid climates. Along the upper St. Johns River Basin in the southeast coastal plain inland saline wetlands occur, formed by fossil saline groundwater. The goal of this study was to describe and evaluate the distribution of species along environmental gradients in the inland saline wetlands of the upper St. Johns River Basin. In June 2022, species composition and cover were assessed at 82, one square meter plots at the Buck Lake Conservation Area (BLCA) in Volusia County, Florida. Soil samples were collected from each plot and electric conductivity, pH, total carbon, total nitrogen, soil color, and soil type were analyzed. Elevation was estimated at each plot from a digital elevation model. Hierarchical agglomerative clustering and the silhouette method determined 9 optimum vegetation assemblages. The constrained correspondence analysis accounted for 22.5% of the variation in site by species distribution and CCA model permutation found that electric conductivity, elevation, soil color, soil type, and canopy closure were significant environmental variables.