Spectral reflectance of hydrophytes

Identification of hydrophytes will improve the delineation and classification of wetlands on remotely sensed imagery. Spectral reflectance measurements of 10 species of hydrophytes were made with an Exotech radiometer during 3 phenological stages, flowering and early seed, senescent, and early emergent. Reflectance data were analyzed to determine significant ( P < 0.5) differences between species in each of 4 spectral regions during each phenological stage. Eight species had significantly ( P < 0.05) different reflectances during the flower and early seed stage. Among the 10 species, only one could not be spectrally isolated during at least 1 phenological stage. The results indicate that films sensitive to both visible and infrared spectra (e.g., Ektachrome infrared) should enable recognition of different species of hydrophytes.