Ew. Ramsey et Jr. Jensen, REMOTE-SENSING OF MANGROVE WETLANDS - RELATING CANOPY SPECTRA TO SITE-SPECIFIC DATA, Photogrammetric engineering and remote sensing, 62(8), 1996, pp. 939-948
Remote sensing was examined as a tool to describe the spectral and str
uctural changes within and between mangrove species and community type
s. To accomplish this goal, high-resolution canopy reflectance spectra
were obtained at 21 mangrove sites in southwest Florida. This was in
addition to leaf spectra, canopy closure, height, and species composit
ion from a number of these sites. High relative variability typified m
easurements of canopy reflectance spectra, canopy height, and percent
species composition, while leaf reflectance variances within species (
black or red, about 0.04 to 0.06 percent) were higher than between spe
cies (about 0.02 percent). A transformed canopy closure variable - Lea
f Area Index (LAI) - was low with little variance, and it was signific
antly correlated to canopy height but not to species composition. Mean
reflectances were generated for the blue, green, red, and near-infrar
ed (NIR) wavelength regions from the obtained canopy reflectance spect
ra by using either user-defined bandwidths or bandwidths defined for t
he Advanced Very High Resolution Radiometer, Thematic Mapper, and XMS
(SPOT) sensors. Results from these sets of reflectances in combination
with correlation analyses suggest blue and red reflectances were redu
ndant as were SPOT panchromatic and green reflectances and all normali
zed difference vegetation indexes derived for each set of NIR and red
reflectances. Eighty-four percent of the LAI variance was explained by
using any generated normalized difference vegetation index; however,
species composition was not correlated to any combination of reflectan
ce bands or vegetation index.