IMPROVING SEAGRASS MAPS OF FLORIDA'S SPRINGS COAST THROUGH DIGITAL IMAGERY

摘要

Digital imagery (1 ft resolution) was collected for Florida Springs Coast (70 mile stretch of coastline north of Tampa Bay) in April 2007 for the purpose of mapping the extensive seagrass beds of this region. This was the first time digital imagery was used in this region. The new imagery provided improvements in positional accuracy, image resolution and clarity, and enhanced detail of seagrass density. This paper compares the mapping results of the 2007 digital imagery to previous mapping efforts that used film imagery in 1985 and 1999 (Continental Shelf Associates 1985, and SWFWMD 2001). The seagrass coverage completed in 1985 was mapped through a combination of low resolution film imagery (scale 1:40,000) and underwater diver transect data. The seagrass coverage produced in 1999 used true color film imagery (1:24,000) with a scanned digital resolution of 1 meter. The use of digital imagery in 2007 resulted in a higher intensity of line work and delineation of seagrass polygons when compared to the 1985 and 1999 maps. The total area of dense seagrass was similar between the 2007 and 1985 coverages, but was substantially different between the 2007 and 1999 coverages. The total area of sparse seagrass and area of patchy seagrass calculated in 2007 were substantially different from the areas calculated for these classifications in 1985 and 1999. The 2007 digital imagery also revealed new information on other important benthic habitats of the Springs Coast and showed promising results for mapping hardbottom habitat and for distinguishing between areas dominated by seagrass and those dominated by macroalgae. A future phase of this project is currently under planning to map hardbottom habitat of the Springs Coast.