Announcing the Final Examination of Gabriel Benson for the degree of Master of Science in Biology
Fringing seagrass beds are important components of coastal ecotones. Their association with shoreline morphology and shoreline restoration, however, is poorly understood. We combined GIS analyses with field-based monitoring to better understand intra-ecotone associations between shorelines and fringing seagrass beds. Using GIS analyses of aerial imagery, shoreline characterization models, and seagrass coverage models, the relationship between shoreline morphology, erosion, and fringing seagrass persistence was examined in Mosquito Lagoon, FL between 2011 and 2021. For the field-based portion of the study, fringing seagrass beds growing adjacent to restored, living shoreline segments were monitored throughout the 2023 growing season (March – November). All shorelines had been stabilized 2-3 years prior. Nearby, uneroded shoreline segments served as positive controls. The geospatial portion of the study found that yearly seagrass persistence was correlated with shallow subtidal slope angles and decreased rates of erosion. Field-monitoring found seagrass (primarily Halodule wrightii), growing adjacent to all sites, although shoot density was significantly greater at control sites. The site with the greatest shoot density also had the shallowest subtidal slope angle; this validates the models from the geospatial portion of the study. Broadly, this study illustrates interconnection between intertidal and subtidal components of a coastal ecotone. We therefore recommend that coastal managers and restoration practitioners holistically consider the entirety of the ecotone when designing restoration projects or experiments. Specifically, we recommend that measurement of subtidal slope angle be incorporated into living shoreline monitoring protocols, as this represents a potential mechanism by which intertidal deployments can positively impact subtidal communities.
Committee in Charge:
Dr. Linda J. Walters
Dr. Melinda Donnelly
Dr. Chase Mason
Lori Morris
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