Análise multitemporal da evolução de áreas de manguezais na ilha do Maranhão com dados de sensoriamento remoto

The main objective of this study is to analyze the evolution of mangrove areas of Maranhão Island, Northeast Brazil, considering a multi-temporal approach (2010 to 2015), evaluating qualitatively and quantitatively the changes occurred in the vegetation cover. We used Landsat 5 TM and Landsat 8 OLI satellite images from 2010 and 2015 respectively, obtained from the USGS website and process with QGIS software. The mangrove areas was done through visual interpretation using NDVI and RGB composition for later vectorization. Its areas were calculated obtaining a total area of mangrove for the year 2010 and for 2015, thus obtaining a comparison. The result of multitemporal analysis show a reduction in the mangrove area in this interval of five years and that the remote sensing was an efficient tool to detect this change. This work subsidy the studies on the effects of coastal erosion for the ecosystem and the implications for sea level rise.