Discrimination of 3 dominant mangrove species from the Pacific coast of Mexico by spectroscopy on intact leaves

Abstract

Spectral discrimination of mangrove leaves is the first step in classifying remotely sensed imagery of mangrove forests. The objective of this study was to analyze spectroscopic data on leaves from the upper and lower parts of mangrove canopies to discriminate species and physiognomic types. Leaf samples from the upper and lower parts of the canopies of 3 mangrove species (Avicennia germinans, Laguncularia racemosa, and Rhizophora mangle) in 2 physiognomic types (basin and fringe) were collected during 2 seasons (dry and rainy). Probability distribution and first-derivative plots were generated for every wavelength (450–1,000 nm) detected in all samples. With the plots, optimal wavelengths were selected and subsequently verified with a canonical discriminant analysis. Results indicated that all species in basin mangrove forests showed a unique distinction between the upper and lower leaves during the dry season. By contrast, species in fringe mangrove forests did not show this difference during both seasons. Optimal wavelengths for species discrimination were located between 540–560 nm and 700–720 nm, which correspond to the green and red-edge wavebands, respectively. Future studies using remote sensing data with the aforementioned wavebands can be conducted to discriminate physiognomic mangrove forest types and to increase accuracy in the classification of mangroves at the canopy level on the Pacific coast of Mexico.