Spectral characterization of mangrove leaves in the Brazilian Amazonian Coast: Turiaçu Bay, Maranhão State

Abstract

Mangrove communities are tropical systems which have fewer species than tropical forests, especially in Latin America and display a single architecture, usually lacking the various strata commonly found in other forest ecosystems. The identification of mangrove communities by orbital data is not a difficult task but the most interesting challenge is to identify themselves by the dominant species. The first step toward that floristic identification is the spectral characterization of detached leaves. Leaves from four species of mangrove trees were spectrally characterized considering the Directional Hemispherical Reflectance Factor (DHRF) determined through radiometric measurements using an integrating sphere LICOR 1800 attached to a spectroradiometer SPECTRON SE-590. In the visible bands (0.45-0.69 µm) the button-shaped mangrove Conocarpus erectus was brighter and the red mangrove Rhizophora mangle was darker than the other two species which shows very close DHRF values. Otherwise the black mangrove Avicennia germinans and the white mangrove Laguncularia racemosa can be distinguished from one another in the Near Infra Red (NIR) region (0.76-0.90 µm and in this region of the spectrum the DHRF of C. erectus and R. mangle become very close.

Spatiotemporal Variation in Mangrove Chlorophyll Concentration Using Landsat 8

“…Likewise, Flores-de-Santiago, Kovacs and Flores-Verdugo [22,32] reported similar CC ranges per species; the highest CC in R. mangle and lowest for L. racemosa and A. germinans was in the Mexican Pacific. In Brazil, Rebelo-Mochel and Ponzoni [78] reported the highest reflectance in the visible bands for C. erectus and lowest for R. mangle, confirming our results. However, they did not measure pigment concentration.…”

“…We did not carry out leaf anatomical measurements; however, the low NIR reflectance of R. mangle and significantly higher reflectance of A. germinans would suggest differences in leaf morphological characteristics. Rebelo-Mochel and Ponzoni [78] also reported higher reflectance in the NIR for A. germinans. In addition, Lima et al [79] reported significantly lower palisade, spongy parenchyma, and total leaf thickness for R. mangle.…”

Semi-Automated Object-Based Classification of Coral Reef Habitat using Discrete Choice Models

“…These efforts have involved region-merging segmentation together with maximum likelihood, nearest-neighbor, and integrating pixel and object-based approaches, and receiver operating characteristic curve analysis [113,114]. Spectral analysis has been done to differentiate between several species [115,116]. Specifically, using WV2 satellite data, as used in this study, work has been done to characterize mangrove vegetation using semi-variograms combined with field data and visual image interpretation, looking at different object and pixel resolutions, and using support vector machines [117][118][119].…”

Feeding activity of the cayenne pompano Trachinotus cayennensis (Cuvier 1832) (Perciformes, Carangidae) in estuaries on the western coast of the state of Maranhão, Brazil

“…The state of Maranhão has the second largest coast of Brazil, with 640 kilometers of coast, and the largest hydrographic basin in the Northeast, generating a combination of large tides and large perennial rivers. The Maranhão western coast includes the area between the mouth of the Gurupi River and the Maranhense Gulf, forming a system called Reentrâncias Maranhenses, characterized by the conformation of a fairly trimmed coastline, consisting of an expressive set of islands, peninsulas and bays, cut by rivers streams and tidal channels filled with clay and silt which foster the development of mangroves (El-Robrini et al, 2006;Rebelo-Mochel and Ponzoni, 2007). In addition, the high concentration of nutrients and other favorable environmental conditions, such as thermal gradients and variable salinity, and the exceptional conditions of shelter and reproduction support and the initial feeding of some marine and estuarine species, make this region one of the main focuses of attention in relation to environmental conservation and the maintenance of its biodiversity (Lefèvre et al, 2017).…”