Mapping and Monitoring Seagrass Communities

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The Office of Coastal and Aquatic Managed Areas (CAMA) is mapping and monitoring seagrass communities in several locations around the state. Different types of remote sensing, such as high resolution satellite imagery, hyperspectral imagery, or LiDAR, can be used to create baseline maps over large areas. These maps can be used to determine seagrass density, coverage, species and prop scar damage. They can also be used to determine changes in each of the above parameters from maps generated from earlier images. High resolution satellite imagery of St. Joseph Bay was collected in November 2010 and is being compared to hyperspectral imagery from October 2006 to identify changes.

Elsewhere in the state, the Coral Reef Conservation Program is conducting benthic habitat mapping in northern Miami-Dade County. This effort was led by Nova Southeastern University Oceanographic Center National Coral Reef Institute with funding from NOAA, FDEP and FWRI. The benthic habitat mapping efforts employed a combined-technique approach combining several types of imagery and ground-truthing. Of the 240.31 km2 mapped, the polygon totals indicated 16.55% was Seagrass. Notable was south of Government Cut, which showed a wide area of extensive seagrass beds dominated by turtlegrass (Thalassia testudinum).

Big Bend Seagrasses Aquatic Preserve is producing baseline seagrass and submerged resource maps for Taylor County. Terra Ceia Aquatic Preserve also conducts photo interpretation in four year intervals.

Hyperspectral imagery can provide exceptional detail with even submerged resources.

Quadrats are used at each station to ensure that the same area is being measured.

This large-scale mapping is complemented by ground-truthing in several preserves, including St. Joseph Bay Aquatic Preserve, Terra Ceia Aquatic Preserve and the Charlotte Harbor aquatic preserves. Annual and bi-annual monitoring is conducted at the same stations within each preserve. Measurements of species composition, percent coverage, blade length, shoot density, water depth, sediment, and epiphyte load are taken at each station.