REPORT SFRC-86/03 

Vegetation Cover Types of 

Shark River Slough, Everglades NP 

Derived from LANDSAT 

Thematic Mapper Data 

3 1199 01103 6665 Everglades National Park. South Florida Research Center. P.O. Box 279. Homestead, Florida 33030 
TABLE OF CONTENTS 

INTRODUCTION.. ............................... ~.

METHODS .............................................................. 1 

RESULTS.. .................om........................ ..e..0m.0000..a002 

Vegetation Cover Types ........................................... 2 

Other Features ....................................... ............4 

ACKNOWLEDGEMENTS ..................................................... 5 

LITERATURE CITED.... ................................................. 6 
VEGETATION COVER TYPES OF SHARK RIVER SLOUGH, 

EVERGLADES NATIONAL PARK, DERIVED FROM 

LANDSAT THEMATIC MAPPER DATA 

Lance H. Gunderson, David P. Brannon* and Gary Irish* 

South Florida Research Center 

Everglades National Park 

Homestead, Florida 33030 

and 

*NASA Earth Resources Laboratory 

National Space Technology Laboratories 

Mississippi 

January 1986 
Gunderson, Lance H., Brannon, David P., and Irish, Gary. 1986. 

Vegetation Cover Types of Shark River Slough, Everglades National Park, 

Derived from Landsat Thematic Mapper Data. South Florida Research 

Center Report ~~~~-86/03. 
INTRODUCTION 

Documentation of the vegetation resources of Everglades National Park is 

one tool used by the National Park Service to meet management objectives. 

Information from time-series analysis can be used to evaluate vegetation 

changes, and therefore determine success or failure of resource 

preservation. In addition, vegetation analyses may be used .to test 

efficacy of wide-scale management actions, such as experimental water 

deliveries authorized by Congress (PL 98-181). The type of vegetation 

analysis examined during this study is the depiction of spatial patterns 

of vegetation cover types or plant associations using LANDSAT IV Thematic 

Mapper data. 

Data from previous LANDSAT satellites have been used in the past to map 

various features of southern Florida wetlands and Everglades National 

Park. Higer et al. (1970) used Multi-Spectral Scanner (MSS) data to map 

hydrologic patterns of the Everglades. Rose and Rosendahl (1979, 1983) 

mapped the distribution of four "hydro-biologic" zones in the Shark River 

Slough of Everglades National Park. Capehart et al. (1977) found limited 

applications of the MSS data to map the distribution of an exotic tree, 

Melaleuca quinquenervia, throughout southern Florida. 

The LANDSAT IV satellite is equipped with a Thematic Mapper Sensor (TM), 

which provides improvements in both spatial and spectral resolution over 

the older MSS sensor. The TM data represent scaled values of reflectance 

within seven bands in the electromagnetic spectrum. The resolution of 

these data is such that each picture element (pixel) on the earth is 

approximately 30m x 30m. Since the sensors scan wavelengths in the near, 

mid, and thermal infra-red region of the electromagnetic spectrum, 

environmental parameters such as soil moisture and temperature can be 

inferred during analysis of the data set. The increased spectral 

resolution of the TM may offer increased separability of wetland 

vegetation cover types (Dottavio and Dottavio 1984). Data from the TM 

sensor should produce an improved vegetation map of Everglades wetlands, 

because of the insensitivity of previous sensors to map the spatially 

variable features as well as the small size of some vegetation features 

such as tree islands or hammocks. 

We present in this report the first application of Thematic Mapper data to 

map the vegetation of Everglades National Park. The intent of this report 

is to provide corollary information to the map, including how the map was 

derived, and a description of the cover types mapped. 

METHODS 

The LANDSAT data were collected on 20 December 1982, and cover the scene 

from row 15 pass 42. The data were partitioned to cover the area over 

Shark River Slough in Everglades National Park. The study area is bounded 

on the north by Tamiami Trail (US 41) or a parallel at approximately 25.45 

degrees north latitude. The southern border of the study area is 25.20 

degrees north. The western boundary is 80.57 degrees west longitude. The 

eastern boundary of the study site was drawn parallel to the main axis of 

the slough in order to exclude upland areas of the park and developed 

areas outside the park. The study area is predominantly freshwater 

wetlands, with small areas of mangroves included in the southern 
portions. These mangrove areas are subject to very infrequent inundation 

by saline waters (generally only during extreme droughts or storm 

'periods). The study area is named the Shark River Slough because the 

large freshwater drainage or slough supplies water to a myriad of rivers 

and creeks within the mangrove zone, the largest of which is the Shark 

River. 

The data were analyzed at the NASA Earth Resources Laboratory, National 

Space Technology Laboratories, in Mississippi. Analysis was done on a 

perkin-~lmer 3222 mini-computer system using the NASA Earth Resources 

Laboratory Applications Software (ELAS). The data were geographically 

rectified using known control points within the data set to develop a set 

of mapping equations which transformed internal x-y image coordinates into 

coordinates of the earth based on the Universal Transverse Mercator (UTM) 

Projection. Data from bands (3,4,5,7) were used to develop an 

unsupervised classification of 57 spectral classes. These classes were 

aggregated and assigned to various vegetation cover types based upon 

ground-truth information collected within the study area. The vegetation 

cover types chssen are primarily based on common associations of 

macrophytic species, but also include factors such as density of the 

vegetation, abundance of lower plant forms (such as periphyton) as well as 

substrate characteristics (type and moisture content). 

RESULTS 

Vegetation Cover Types 

The accompanying map illustrates the spatial distribution of the 

vegetation cover types. These can be characterized as forested or 

graminoid associations. The forest types include the mangrove groups, 

freshwater swamp forest and tropical hardwood hammock. The grass-like 

associations are the sawgrass marshes, spikerush marshes, and 

muhly/sawgrass prairies. Some groups are combinations of vegetation 

associations, and are included with the dominant type. 

We identified two forest types within the saline-water influenced zone of 

the map. Both types are dominated by red mangrove, Rhizophora mangle. 

The maroon color on the map depicts the distribution of red mangrove 

stands with relatively dense canopy cover. Other woody species such as 

buttonwood, Conocarpus erectus, may be found within this type. However, 

the pink color represents monospecific stands of red mangroves. These red 

mangroves have a stunted or dwarfed growth form and in some areas are 

scattered or form low density stands. The dwarf mangrove category has a 

signature (the combination of reflectance values in the various wavelength 

bands) which includes both water and the scattered mangrove vegetation. 

This category includes the mangrove fringe found along creeks which make 

up the upper reaches of the Shark River and the scattered dwarf mangroves 

found in the interface region between the freshwater marshes and mangrove 

zone. 

The upland mixed hardwood forests are depicted by red on the map. These 

forests have a closed canopy and are dominated by tropical trees and 

locally referred to as tropical hardwood hammocks, although temperate 

genera are found in these associations. These forests are on elevated 

limestone outcrops, and are free from standing water under all but extreme 
circumstances. Wild tamarind, Lysiloma latisiliquum, gumbo-limbo, Bursera 

simaruba, strangler fig, -- Ficus aurea, and cabbage palm, Sabal palmetto, 

are the tropical species which dominate many of these sites. Liye oak, 

Quercus virginiana, is a common temperate species found in the overstory 

of these forests. 

The swamp forests of Shark River Slough are locally referred to as tree 

islands, a name descriptive of these forests which are surrounded by marsh 

vegetation. The swamp forests are represented on the map by brown and are 

comprised of a diverse assoc'ation of hydrophytic hardwoods. Common 

overstory species include: swamp bay, Magnolia virginiana; dahoon holly, 

Ilex cassine; willow, Salix caroliniana; pond apple, Annona glabra; and 

wax myrtle, Myrica cerifera. These species form a relatively closed 

canopy over hardwoods such as cocoplum, Chrysobalanus icaco, and 

buttonbush, Cephalanthus occidentalis, as well as fern species such as the 

large leather fern, Acrostichum danaeifoliuin. 

Two of the mapped vegetation categories are composite categories 

consisting of a mixture of forested and non-forested areas. One type is a 

combination of wet prairie and some swamp tree species. The other 

category is characterized as tall, dense sawgrass with a component of 

swamp trees. 

The gold color on the map shows the distribution of the wet prairie and 

swamp tree category. Stunted or dwarf cypress forests are included in 

this category. The cypress, Taxodium ascendens, has a stunted growth form 

due to poor growth conditions. The trees are scattered and form a sparse 

canopy cover (less than 20%) in a savannah-like setting. These type 

cypress forests are difficult to detect from these data, because of their 

scattered, sparse distribution and that the trees were leafless during the 

time of scanning (~ecember). The understory is an association of sedges 

and grasses dominated by sawgrass, Cladium jamaicense, and grasses such as 

muhly, Muhlenbergia filipes, Schizachyrium rhizomatum. This category also 

includes small (less than 50m2) tree islands scattered through the 

prairie areas. The species found within these tree islands are the same 

ones listed above for the swamp forest communities. The small tree 

islands are included in this category because the signature within each 

pixel is dominated by the prairie association characteristics yet has a 

component of the mixed hardwood islands. 

The green color on the map represents areas of tall, dense sawgrass, 

Cladium jamaicense. These sites may also support scattered hardwood tree 

species such as pond apple, Annona glabra, and willow, Salix caroliniana, 

which emerge above the sawgrass. Sawgrass attains heights of 3 m and 

forms such dense, impenetrable stands. The tall sawgrass cover type is 

typically found at the downstream end or tail of the teardrop-shaped tree 

islands. 

The brown and yellow colors depict phases of wet prairie-type vegetation 

found growing on marl substrate. Short-stature sawgrass grows in these 

associations along with other grasses, sedges and forbs, with varying 

degrees of cover. Dominant species include muhly, Muhlenbergia filipes, 

black top sedge, Schoenus nigricans, and sawgrass. Sawgrass appears to 

have a higher density and cover within the brown class. The yellow areas 
had deeper water depths at the time of data collection than the brown 

areas, and the signature reflects more of water component than in the 

brown grouping. The yellow color group also has a component of periphyton 

which influenced the reflectance classification. 

The white color portrays areas of very high reflectance. The high 

reflectance is due to an almost complete coverage of the ground surface by 

a dense mat of periphyton. The periphyton mat is comprised of various 

species of blue-green, green and brown algae. The blue-green algae 

preclpitate calcium carbonate, which may contribute to the high 

reflectance. The mat floats at the water surface, precluding the 

influence of water on the reflectance. The white areas in the northern 

part of the map have a component of sawgrass and muhly type macrophytic 

vegetation, whereas the white areas in the south have very sparse 

scattering of sawgrass. 

The medium blue color represents areas of short-stature (heights less than 

1 rn) sawgrass. Sawgrass in these areas forms typically monospecific 

stands. The sawgrass forms a dense ground cover. These areas have not 

been burned in a number of years, and the accumulation of standing dead 

leaves increases the apparent density of cover. These areas of sawgrass 

are also found on peat soils, indicative of longer periods of inundation. 

The blue category also includes some standing water, as water depths were 

approximately 6-10 inches during the time of data collection. 

The darkest bl~e~color covers areas of relatively open water. This group 

includes areas of open water, with no emergent vegetation, as well as 

slough areas with sparse, emergent plant cover. The dominant plant in the 

slough category is spikerush, Eleocharis cellulosa. Maidencane, Panicum 

hemitomon, may be locally dominant within the slough type. The majority 

of the area within the slough-type is covered by submerged plants of the 

genera Utricularia. A submerged periphyton mat is found on and around the 

matrix of Utricularia stems. This mat is much darker in color and appears 

brownish to the eye, hence is not highly reflective like the other type of 

periphyton. 

The lightest blue color depicts a class which is primarily sparsely 

vegetated spikerush and open water over marl-type substrate. 

Other Features 

Other features are depicted on the map, some of which are natural whereas 

others were created by human activity. The natural features apparent on 

the map include the margins or borders of the central part of Shark River 

Slough. The eastern border is a fairly well-defined transition between 

marl and peat substrates, and is shown between the yellow and blue 

colors. The western border of the central slough is not as marked a 

transition, as shown by the zone of mottled yellow, blue and white, 

indicative of the spatial heterogeneity in the topography, hydrology and 

vegetation. Other notable features are the rock reefs, or bedrock 

outcrops. These elevated ridges are colonized by hardwood vegetation, and 

appear as thin lines oriented northwest to southeast and located in the 

upper and lower central segments along the eastern border of the map. 
The anthropogenic features on the map include roads, canals and off-road 

vehicle trails. The Shark Valley Loop Road in the northern central area 

of the map is visible, as is the main park road of Everglades National 

Park (southeastern corner). Canals such as the L-67 extension and Blue 

Shanty Canal are also apparent. Swamp hardwoods line the Blue Shanty 

Canal, which resulted in the canal being outlined in reddish brown (the 

swamp hardwood category). Airboat trails are visible in northeast Shark 

River Slough. These areas have a signature of open water, due to removal 

of standing vegetation by rep-eated passes with an airboat. Vehicle 

trails, caused by airboats and swamp-buggies, appear as white in the 

northwest corner of the map. 

ACKNOWLEDGEMENTS 

This work effort was supported by funds from both the National Aeronautics 

and Space Administration, Earth Resources Laboratory and National Park 

Service, Everglades National Park. We wish to thank the efforts of Hollis 

Davis, John Stenberg, Alan Herndon and Sharon Hatch in assisting with 

ground truth data collection. 
LITERATURE CITED 

Capehart, B. L., Ewel, J. J., Sedlik, B. R., Myers, R. L.. 1977. Remote 

sensing of Melaleuca. Photogrammetric Engineering and Kemote Sensing 

45: 197-206. 

Dottavio, C. L., and Dottavio, F. D. 1984. Potential Benefits of New 

Satellite Sensors to Wetland Mapping. Photogrammetric Engineering and 

Remote Sensing 50:599-606. 

Higer, A. L., Kolipinski, M., McThomson S., and Thomson, F. J. 1970. 

Applications of Multispectral Data Collection and Processing Techniques 

Applied to Hydrobiological Investigations in Everglades National Park, 

Florida. March 1970, American Society of Photogrammetry. 

Rose, P. W., and Rosendahl, P. C. 1979. An Application of Landsat 

Multispectral Imagery for the Classification of Hydrobiological Systems, 

Shark River Slough, Everglades National Park, Florida. Technical Report 

T-544. ~omestekd FL: Everglades National Park, South Florida Research 

Center. 

Rose, Y. W., and Rosendahl, P. C. 1983. Classification of Landsat Data 

for Hydrologic Application, Everglades National Park. Photogrammetric 

Engineering and Kemote Sensing 49:505-511.