Submerged Aquatic Vegetation

Overview

Conch in seagrass. Courtesy Heather Dine, Florida Keys NMS

The Challenge

Seagrasses and other types of submerged aquatic vegetation (SAV) play an essential role in coastal ecosystems in the Gulf of Mexico. By providing habitat to juvenile organisms, including a variety of endangered and commercially important species, SAV beds are both ecologically and economically valuable. However, over the past century, the health and coverage of SAV has declined. Dredging, direct filling, propeller scarring, over-water structures, and other forms of nearshore development have caused SAV loss. Land use changes in the adjoining watersheds and associated impacts are also believed to contribute to SAV loss.

Many organizations are working throughout the Gulf to restore its ecosystems. Every day resource managers must make decisions about complex problems, such as which areas are most appropriate to restore, and having a credible scientific basis for these decisions is critical. They also need to plan and implement cost-effective restoration to maximize results for the money spent.

Ecological conceptual models and analytical models for prioritization are two restoration planning tools that can provide such support. Conceptual models are becoming useful tools to facilitate discussion and documentation of our understanding of the cause and effect relationships that influence habitat structures. Analytical models, coupled with local knowledge, can help resource managers understand the probability of that proposed management actions, such as restoration, will be successful before they are implemented.

GoMRC’s Contribution

In response to this need, GoMRC developed a set of tools to help coastal resource managers better plan wetlands restoration efforts. The tools developed focus initially on SAV as one type of coastal wetland structure receiving significant attention from resource managers throughout the Gulf of Mexico--and on a limited geographic area, Mobile Bay, Alabama--for demonstration purposes. The toolset can be easily adapted to other types of coastal wetland structures, such as mangroves or tidal marshes, and applied in other geographic areas. Extending this toolset will be the focus of future work.

Coastal wetlands scientists developed a Conceptual Model for SAV with input from resource managers familiar with the Mobile Bay demonstration site and the current conditions of SAV. The conceptual model provides a scientific-based overview of relationships and processes that influence the health of SAV in Mobile Bay, such as the availability of light and the presence of “stressors” like seawalls. The basic conceptual model for SAV defines various stressors, controlling factors, processes and functions that influence and are influenced by SAV species, and describes the relationships among them. The Conceptual Model Explorer provides a web-based visual representation of these relationships, access to associated datasets, and the ability to create, edit and share new conceptual models.

To facilitate decisions related to coastal ecosystem restoration, and specifically the management of SAV, GoMRC developed the SAV Restoration Prioritization Toolset. The SAV Restoration Prioritization Toolset uses numerical models to examine environmental factors that influence the health of SAV and change in SAV cover over time and provides recommendations based on the potential for restoration success. Local GIS datasets, bathymetric information, and datasets derived from NASA products are used to characterize elements of the conceptual model with numerical models. The Restoration Prioritization Toolset can be accessed as a web-based tool through the Conceptual Model Explorer and through the ArcGIS Toolbox for Restoration Prioritization for users with familiarity and access to ArcGIS tools.

More Information

See Primer on Ecosystem Restoration (pdf) for more information on the planning process for coastal ecosystem restoration and restoration strategies that can be employed.