Symposium on Remote Sensing for Resources Development and Environmental Management / Enschede / August 1986 
Mangrove mapping and monitoring 
John B.Rehder 
University of Tennessee, Knoxville, USA 
Samuel G.Patterson 
University of Virginia, Charlottesville, USA 
ABSTRACT: Mangroves and other ecosystems of the Marco Island area of Florida, were analyzed for 
boundary interpretations and changes in acreage between 1952, 1962, 1973, and 1984. Comparisons were 
made between Landsat MSS data and aircraft data. It was found that medium and high altitude black and 
white and color infrared imagery were best for mapping species of red mangrove (Rhizophora) and black 
mangrove (Avicennia) and their ecological communities. Mapped data were entered into a geographic 
information system (GIS) data base to produce maps of total mangrove acreages, and measures of 
landscape change in the mangrove communities from 1952 through 1984. 
1. MANGROVE ECOLOGY 
This project focuses on the detailed mapping 
of coastal mangrove ecosystems in the Marco 
Island area of southwestern Florida. Mangroves 
are tropical and subtropical trees and shrubs 
in coastal areas located between the high 
water mark of spring tides and mean sea level 
(MacNae, 1968). 
The major mangrove species are red mangrove 
(Rhizophora mangle 1.) and black mangrove 
(Avicennia germinans). Red mangrove have a 
closed canopy and narrow,thick leaves. The 
spongy mesophyll of the red mangrove leaf 
structure produces high spectral reflectance 
responses in the near infrared part of the 
electromagnetic spectrum. Conversely, black 
mangroves have a more open canopy and greater 
tree height, and have thin, translucent leaves 
that exhibit lower spectral reflectance 
responses in the near infrared. These diff 
erences are important for the detection and 
identification of species and ecological zones 
and for measuring the impact on detrital leaf 
litter transport for nutrients in the food 
chain. Mangroves occur in specific ecological 
zones on islands, coastal and riverine shore 
lines, and in mainland locations. 
Mangrove ecological communities are: 
1. Red Fringe - red mangrove species which 
occur along marine shorelines. 
2. Red Riverine- red mangrove species that 
occur as corridors of thick vegetation along 
streams and narrow estuaries. 
3. Black Basin- black mangrove species 
found in the centers of islands and 
mainland interior locations. 
4. Mixed- communities of a mixture of both 
species of red and black mangrove. 
5. Uplands - composed of topographic highs 
(2 to 10 feet elevation) containing hardwood 
hammocks, relic orchards, coconut, palm, and 
palmetto (Lugo and Snedaker, 1974). 
Mangrove ecosystems are important to the 
stability of coastal lands, to the main 
tenance of water clarity, and to the signifi 
cant productivity of the esturine eco 
systems. The transportation of mangrove 
leaf litter forms the basis of the coastal 
marine food web. The rich nutrients from 
the detrital export support some 75Ï of the 
Gulf marine commercial and sport fisheries 
in southwest Florida. Among the mangrove 
species and ecological communities, red 
riverine mangrove will transport 94Ï of its 
productive nutrients to the food chain. Red 
fringe mangrove will transport 42t of the 
total leaf litter it produces. However, 
black basin mangrove, which can produce only 
3/5 the leaf litter that red riverine pro 
duces for an equal area, will transport only 
21Ï of its leaf litter to the marine food 
chain (Twilley, 1982). Therefore it is 
important to recognize the need for species 
identification for ecological zone mapping 
and management. 
2. MAPPING MANGROVES 
Since 1974, general estimates of the geo 
graphical extent of Florida's mangrove eco 
systems have been made but specific species 
mapping and inventories of mangrove com 
munities and zones have been limited. In 
1979, Butera and Shines mapped the south 
western Floridian mangroves with Landsat MSS 
data. The results provided general cover 
age of the mangrove ecosystem but lacked 
accurate demarcation of species and zones 
(Butera,1979/ Shines, 1979). The intricate 
land and water interface in mangrove 
communities and the subtle vari 
ations among species present a challenge 
to mapping mangrove communities from Landsat 
MSS data. 
2.1 Landsat and aircraft data comparisons 
In a visual comparison, on a Landsat MSS 
image, islands and shorelines can be de 
tected and mapped because of reasonable 
contrasts in spectral reflectances at the 
land-water interface. However, with man 
groves often growing in narrow linear bands 
of 20 to 30 meters width, the 80 meter 
ground resolutions of Landsat MSS data can 
not reveal the same spatial resolutions that 
can be obtained from aircraft imagery. 
In a comparison of digital remote sensing 
products, digitized aircraft data enabled 
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