Avaliação espaço-temporal da vegetação por meio de índices de vegetação no Município de Santa Terezinha - Ba

Abstract

The Caatinga, the largest biome with exclusively Brazilian distribution, is part of a global biome called “Seasonally Dry Tropical Forests and Shrubs)” whose acronym is FATSS. The Caatinga has the greatest species richness among the FATSS in the new world and holds enormous value for biodiversity and conservation of the fauna and flora of drier vegetation. However, the biome has had a good part of its native vegetation cover deforested, mainly in recent years due to the use of native firewood, which is unsustainably and illegally exploited for domestic and industrial use, in addition to grazing and converting its natural vegetation for pastures and agriculture. The main objective of this research is to estimate the NDVI, SAVI, EVI and NDWI indices in the municipality of Santa Teresinha - BA, in order to determine which index is most suitable for representing the remaining vegetation using remote sensing techniques. For the monitoring of vegetation cover, images from the Landsat-5/TM satellite for the years 1988 and 2011 and images from the Sentinel-2/MSI satellite for the year 2021 were used, setting the temporal aspect at 33 years. To estimate the NDVI, SAVI, EVI and NDWI indices, the spectral bands referring to blue, green, red, near-infrared and mid-infrared of the images were used, where the indices and statistical data were estimated using the QGIS software version 3.16.6 of possession of its native raster calculator tool. With the maps containing the estimated classes of the indices, it was possible to visualize the dynamics of the vegetation in each year determined in this study and with the statistical data it was possible to define the indices that best suited to represent the characteristics of the vegetation of the municipality. Among the four indices used in this study, SAVI and EVI were the ones that best suited to characterize the area's vegetation in greater detail.