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ABSTRACT:This study aims to analyse the dynamics of land-use and land-cover (LULC) in a selected southern Amazonian area (Brazil), monitoring and distinguishing trajectories in NDVI (Normalized Difference Vegetation Index) variations for the last three decades. The area, with a total of 17336 km², has been subject to significant LULC changes associated with deforestation progress and use of fire. Considering available Landsat time series, it was selected an image per year from 1984 to 2013 (path/row -231/66), at a particular period of year, atmospherically corrected using LEDAPS tools. NDVIs values were generated for each selected image. Furthermore, the images of 1984 and 2010 still underwent a classification of LULC differentiate five categories: water, forest, secondary/degraded forest, savannah/pasture and crop/bare soil. The trajectories in NDVI variation values were analysed by R software, considering intersections of classified categories. The pixels identified as forests on the images of 1984 and 2010 displayed stable trajectories of NDVI values, with average value 0.824 and coefficient of variation 3.9%. While the pixels of savannah/pasture, which was periodically affected by fire, had an average NDVI value 0.585 and coefficient of variation 15,1%. The main regressive trajectory was the transition "forest to crop/bare soil", identifying 1999 as the starting point in the drop in NDVI values, associated with an increase of the deforested areas. Therefore, the results show distinct trajectories associated with NDVIs and LULC changes that assist in better understanding the dynamics of ecological processes and the human impacts operating in the area.

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O estudo das relações entre o fogo e a dinâmica das paisagens brasileiras resulta fundamental para uma melhor compreensão dos processos ecológicos e dos impactos humanos incidentes sobre a dinâmica da paisagem. O presente artigo busca explorar a dinâmica de variação espaço-temporal de ocorrência de queimadas nos biomas brasileiros nos últimos 18 anos (2001-2018), com base no produto MCD64A1 v006 de área queimada e a base de dados de uso e cobertura da terra do projeto Mapbiomas. O Cerrado apresentou 62,2% do total queimado registrado no período analisado, seguido do bioma Amazônia, com 23,5%. Pampa, Mata Atlântica e Amazônia apresentaram uma incidência de queimadas superior a ≈50% em áreas com usos da terra agropastoris, enquanto nos biomas Cerrado, Caatinga e Pantanal as queimadas ocorreram principalmente sobre áreas de formação vegetal natural. Comprova-se o potencial de combinação de uso de produtos derivados de sensoriamento remoto para análise dos padrões de áreas queimadas, gerando-se relevantes informações a respeito das influências antrópicas na alteração dos regimes de fogo.