The flat expanse of sawgrass marsh and mangrove coastline in Everglades National Park, Florida, serves as valuable habitat for a number of unique, rare, or endangered species. Unfortunately, this same expanse, with only about a 5 cm (2 in) increase in elevation per linear kilometer (0.6 mi) inland, makes the region exceptionally vulnerable to the effects of sea-level rise. Slight increases in sea level are expected to lead to disproportionate increases in inundation periods for broad areas in the park, and have already influenced both surface and subsurface saltwater intrusion. Saltwater intrusion has also likely been influenced by reductions in freshwater discharge that have accompanied upstream development over the past century. These hydrologic changes put pressure on the ecosystem, causing a variety of impacts, such as inland migration of plants, variation in species composition, and disruptions of predator-prey relationships (Pearlstine et al. 2010). Salt-tolerant mangrove species have already migrated approximately 3 km (2 mi) inland since the 1940s in parts of the national park, presumably in response to rising sea level (Ross et al. 2000). Understanding these impacts and protecting park resources are critical when one considers that only 10% of all coastal areas that are below 1 m (3 ft) elevation in the eastern United States have been set aside for conservation (Titus et al. 2009). Many coastal resources in Everglades National Park are not protected elsewhere in the United States. Faced with these challenges, our group is examining the factors that regulate variability in the long-term record of sea level maintained at Key West, Florida, located less than 100 km (62 mi) south of the park’s southernmost landward extent. We are also investigating how freshwater management strategies and rainfall fluctuations interact with rising sea level to influence water and salinity levels and plant community composition in the park’s coastal wetlands. This information should eventually assist in determining the potential ecological consequences of rising sea levels in the park’s most vulnerable habitats.