Nekton and Macro-Crustacean Habitat Use of Mississippi Micro-Tidal Salt Marsh Landscapes

Salt marshes have long been recognized as productive habitats that form an important trophic link between the aquatic and terrestrial biomes through the dynamic intertidal zone. This project focused on the distribution of nekton (free-swimming organisms) and common macro-crustaceans within the intertidal to assess the breadth of habitat use by these assemblages based on geo-spatial and hydrological variables. Sampling was conducted on the flooded marsh intertidal in August and September 2011 at three sites in the micro-tidal Grand Bay National Estuarine Research Reserve, MS, using bottomless lift nets and pit traps in a landscape design. The sampled assemblage data were compared with concurrent site hydrological analyses in order to determine how distribution on the salt marsh intertidal may be influenced by defined inundation components (e.g., inundation time and frequency of inundation) and by the distance to the nearest water source. A total of 3238 organisms were collected comprising 12 fish and 13 macro-crustacean species. A two-way nested analysis of similarities (ANOSIM) indicated that the density of the assemblage varied by site (p = 0.1 %) and across the salt marsh intertidal (marsh level (MLV); p = 1.4 %). Overall, assemblages were found to be strongly influenced by the inundation characteristics along the marsh elevation gradient as well as by the unique micro-topography of each site