Coastal wetland response to sea‐level rise in a fluvial estuarine system

Abstract

Coastal wetlands are likely to lose productivity under increasing rates of sea-level rise (SLR).This study assessed a fluvial estuarine salt marsh system using the Hydro-MEM model under four SLR scenarios. The Hydro-MEM model was developed to apply the dynamics of SLR as well as capture the effects associated with the rate of SLR in the simulation. Additionally, the model uses constants derived from a 2-year bioassay in the Apalachicola marsh system. In order to increase accuracy, the lidar-based marsh platform topography was adjusted using Real Time Kinematic survey data. A river inflow boundary condition was also imposed to simulate freshwater flows from the watershed. The biomass density results produced by the Hydro-MEM model were validated with satellite imagery. The results of the Hydro-MEM simulations showed greater variation of water levels in the low (20 cm) and intermediate-low (50 cm) SLR scenarios and lower variation with an extended bay under higher SLR scenarios. The low SLR scenario increased biomass density in some regions and created a more uniform marsh platform in others. Under intermediate-low SLR scenario, more flooded area and lower marsh productivity were projected. Higher SLR scenarios resulted in complete inundation of marsh areas with fringe migration of wetlands to higher land. This study demonstrated the capability of Hydro-MEM model to simulate coupled physical/biological processes across a large estuarine system with the ability to project marsh migration regions and produce results that can aid in coastal resource management, monitoring, and restoration efforts.

The Impact of Lidar Elevation Uncertainty on Mapping Intertidal Habitats on Barrier Islands

“…Our results confirm findings of others, which suggest that lidar DEMs can have a substantial level of vertical uncertainty in intertidal areas [17][18][19], and this uncertainty should be accounted for if data are directly used in classification algorithms for habitat mapping or for use in sea-level rise modeling efforts [42,43]. Our findings highlighted that optimal results with regards to the maximum identification of actual intertidal areas (i.e., highest producer's accuracy) are likely produced when site-specific RTK GPS data are used.…”

Dietary shifts across biogeographic scales alter spatial subsidy dynamics

“…Marsh habitats are being depleted at high rates globally, with >40% of marshes in the USA already degraded or destroyed (Gedan and Silliman 2009). This depletion is especially important in the GoM with marsh habitats subsiding while sea levels continue to rise (Alizad et al 2016). If primary production from marshes is transferred with less efficiency in the GoM in part due to the lack of regular and deep marsh flooding, we may see unique, temporary, and non-intuitive dynamics with regard to marsh-derived secondary production in GoM estuaries in response to continued or accelerated global change.…”

An Earth's Future Special Collection: Impacts of the coastal dynamics of sea level rise on low‐gradient coastal landscapes

“…While Medeiros et al [2015] improved approaches for deriving elevation in marshes, Morris et al [2016] focuses on the collection of data required to inform a biological model of wetland productivity and elevation [Morris et al, 2002;Hagen et al, 2013;Alizad et al, 2016aAlizad et al, , 2016b. Intertidal sediment parameters (e.g., bulk density) derived from data obtained through EESLR-NGOM are combined with samples from over 30 tidal and freshwater wetland sites across 14 states.…”