Habitat Characterization for Submerged and Floating-Leaved Aquatic Vegetation in Coastal River Deltas of Mississippi and Alabama

Salinity and water clarity dictate seasonal variability in coastal submerged aquatic vegetation in subtropical estuarine environments

“…Salinity was the dominant factor driving species assemblages, biomass and species number, matching findings from past studies along the Gulf coast and in other regions (i.e. Carter et al 2009, Borgnis & Boyer 2016, Cho & Biber 2016, Patrick et al 2018. Overall, SAV biomass and species number were consistently higher in the fresh and intermediate assemblages throughout the year.…”

“…Within these areas, SAV species serve as foundation species, yet assemblages, biomass and controls on patterns of intra-annual variation of SAV along this estuarine gradient have not been thoroughly described. In general, greater species diversity and biomass are observed during summer months, with declines in winter months (Dunton 1994, Cho & Poirrier 2005a, while fresher SAV assemblages tend to have higher diversity and biomass compared to brackish and saline assemblages (Chabreck 1972, Cho & Biber 2016. Across the northern Gulf of Mexico, a 2 yr survey documented 14 species of SAV across the estuarine gradient, with up to 11 species occurring within each salinity zone, but significantly greater biomass within the fresher assemblages (Hillmann et al 2016).…”

“…Temporal and spatial variation in SAV assemblages across the salinity gradient likely reflect multiple and co-varying environmental controls. For example, salinity and light availability are often identified as 2 critical controls on individual species and SAV presence (Koch 2001, Cho & Biber 2016, DeMarco et al 2018. However, past studies in Louisiana have reported general trends of deeper waters in upstream freshwater areas of the estuary, as compared to more down-stream saline areas (i.e.…”

Predicting barrier island habitats and oyster and seagrass habitat suitability for various restoration measures and future conditions for Dauphin Island, Alabama

“…Seagrass has generally not been found on the gulf-facing beaches of the island chain in the Mississippi Sound because of high wave energy (Pham and others, 2014). The impact of wind and wave energy on coastal seagrass distribution and growth is rarely incorporated in HSI modeling, but it has been found to be critical and significant in many studies (Newell and Koch, 2004;Cho and Biber, 2016;Saunders and others, 2017;DeMarco and others, 2018). A linear decrease in the probability of seagrass occurrence with exposure was found by DeMarco and others (2018).…”

“…C8), indicating that the seagrass habitat suitability model is related to habitat quality for seagrass distribution and growth. The low coefficient of determination (R 2 ; <0.5) is attributed to (1) the uncertainty in the relation between water quality variables and habitat suitability, (2) the lack of other critical biophysical parameters such as substrate type and nutrients (nitrogen and phosphorus) and historical seagrass presence or absence onsite, (3) the lack of a commonly used light availability parameter (for example, photosynthetically active radiation), and (4) variability in the water quality parameters over space and time (Kemp and others, 2004;Zajac and others, 2015;Cho and Biber, 2016).…”