Broad-Scale Effects of Sea Level Rise on Salt Marsh Nekton

Current models predict sea levels to rise approximately 1.5 meters by the year 2100.  Rates of change in sea level will exceed salt marsh accretion rates in some areas, preventing vertical migration and resulting in a net loss of salt marsh. It is currently unknown what effect salt marsh loss will have on estuarine dependent nekton.  To our knowledge species distribution modeling at the landscape scale for estuarine nekton communities has also not been attempted. This research demonstrates a method that quantifies and maps broad-scale relationships of nekton distribution with landscape characteristics of salt marsh and projects these relationships into the future with sea level rise. Samples were collected from March 2013 – June 2013 in Georgia (USA) estuaries.  Sites were stratified by proportion of marsh coverage and patch size.  A suite of landscape metrics for salt marsh were modeled against counts using a generalized linear mixed model approach. The best model was projected from present conditions to simulated conditions in 2100 using the Sea Level Affecting Marsh Model 6. Results indicate a decline in overall habitat available in coastal Georgia. These findings imply future challenges to management of an estuarine fishery influenced by sea level rise.