Spatiotemporal analysis of mangrove vegetation in a protected area using spectral indices

Abstract Mangrove is an important transitional ecosystem between terrestrial and marine environments, with a typical vegetation (mangrove) that tolerates the intense variation of salinity coming from the tides. The application of remote sensing techniques based on spectral indices enables the development of spatiotemporal monitoring of this vegetation, thus subsidizing ecosystem management. This study aimed to evaluate the spatiotemporal analysis of mangrove vegetation in RESEX Acaú-Goiana based on spectral indices. The study area was the mangrove in RESEX Acaú-Goiana, a protected area of sustainable use in northeastern Brazil between the states of Pernambuco and Paraíba. Images from the TM/ Landsat 5 and OLI/Landsat 8 sensors from 1992, 2006, 2010, and 2019 were used and the normalized difference vegetation (NDVI), normalized difference water (NDWI), and modular mangrove recognition indices were applied. NDVI varied from 0.5 to > 0.75; NDWI, from 0.25 to 0.75; and MMRI, from −0.6 and −0.3. 2019 showed the lowest average of these indices. The evolution of the establishment of carciniculture (shrimp farming) nurseries in the inner portion of the reserve becomes evident, which may result in environmental damage to the ecosystem. Results will serve as input for developing monitoring strategies and managing the reserve.