of lakes (or lagoons) fringed by 

 mangroves and some tropical hard- 

 woods toward the eastern end. South 

 of these lagoons toward Florida Bay 

 the area is dominated by buttonwood, 

 and red, black, and white mangroves, 

 and prairies of salt tolerant (halo- 

 phytic) herbaceous vegetation (Rus- 

 sell et al. 1980). On the eastern 

 side of lower Taylor Slough the 

 coastal lagoons are conspicuously 

 absent, and surface drainage is 

 better defined. This hydrologic 



structuring leads to a vegetation 

 and land form pattern that generally 

 follows and radiates out from the 

 surface drainage pattern. Also less 

 prevalent on the eastern side of 

 Taylor Slough are the broad plains 

 of buttonwood and halophytes. 



Florida Bay 



Florida Bay is a triangularly 

 shaped body of water extending from 

 about U.S. Highway 1 on the north- 

 east to Long Key on the extreme 

 southwest to East Cape Sable, lying 

 north and west of Long Key. For 

 purposes of this report the north- 

 eastern boundary of the bay follows 

 U.S. Highway 1 down to Key Largo. 

 The progressively restricted circu- 

 lation and exchange of water in Card 

 Sound and Barnes Sound act as a 

 barrier inhibiting hydrologic and 

 ecologic exchange between Biscayne 

 and Florida Bays (Tabb et al. 1962, 

 Lee and Rooth 1972). As such the 

 sounds collectively represent a dis- 

 tinct physiographic transition zone 

 between the two bay systems. 



Florida Bay is characterized by 

 numerous mangrove covered islands 

 that represent the above-water pin- 

 nacles of a nearly continuous series 

 of shoals. Fleece (1962) comments 

 that these shoals often seem to 

 occur at roughly right angles to one 

 another. Many of the shoals sur- 

 round areas of deeper water ( > 2 m 

 or 7 ft) which are locally referred 

 to as "lakes". 



The complex topography of the 

 bay system is an important factor in 

 determining the distribution of 

 physical and chemical conditions, 

 and thus subenvironments. As men- 

 tioned earlier, the upper most part 

 of the bay is actually a series of 

 semienclosed sounds which are fairly 

 well isolated from one another 

 hydrologically. Beginning just 



southwest of Blackwater and Little 

 Blackwater Sounds, the mud shoals 

 and islands are not as numerous or 

 continuous, and the area is uniform- 

 ly shallow (0 to 2 m or to 7 ft). 

 Moving toward the Gulf of Mexico on 

 the mainland side, the width and 

 length of the mud banks increases, 

 though the number of islands and 

 their area above water does not. 

 Toward the Keys side, the mud banks 

 are thinner and tend to encircle 

 deeper "lake" areas. 



Turney and Perkins (1972) 

 divide the bay into four distinct 

 subenvironments based on dominant 

 molluskan faunas and physical/chemi- 

 cal factors. The northern subenvi- 

 ronment lies along the northern 

 shoreline toward the Gulf of Mexico. 

 The interior subenviroment is the 

 broad central expanse of the bay 

 which these and other authors (Gins- 

 burg 1956, Gorsline 1963) believe is 

 subject to little or no regular 

 tidal flushing. The Gulf and Atlan- 

 tic subenvironments correspond to 

 those areas influenced by tidal 

 exchange with the Gulf of Mexico 

 and the Florida Keys area, respec- 

 tively. 



2.3 FLORIDA KEYS 



Figure 8 presents a map of the 

 major physiographic features of the 

 Florida Keys. Extensive exposed and 

 sheltered mangrove shorelines domi- 

 nate the surface vegetation of the 

 Keys, particularly on the Gulf of 

 Mexico and Florida Bay side, and on 

 the peripheral keys (e.g., Rodriguez 



21 



