Datasets include hydrology (water level and salinity), net ecosystem exchange of CO2, PAR, and air temperature for a freshwater marl prairie, brackish marsh ecotone, and saline scrub mangrove forest. Data were derived from multiple sources, including two sites from the South Florida Water Management District (SFWMD) DBhydro web database, two sites from the Florida Coastal Everglades Long Term Ecological Research (FCE-LTER) and three AmeriFlux sites in the Southeastern Everglades region. To understand the effects of sea level rise and freshwater management on landscape carbon exchange (C), we measured the net ecosystem exchange of CO2 (NEE) between subtropical wetland ecosystems and the atmosphere along a dynamic salinity gradient. Ecosystems were representative of freshwater marl prairies, brackish marsh ecotones, and saline scrub mangrove forests. In the southeastern Everglades, the magnitude of environmental change was greatest along the coast, where mangrove scrub forests exhibited a greater capacity to maintain CO2 uptake with changing conditions.