Distribuição espaço-temporal das queimadas no bioma Cerrado entre 1999 e 2018

Abstract

The occupation and appropriation of the Cerrado in the last decades was guided, above all, from agricultural activities, which continuously expand over areas of natural vegetation. In this context, fire has been used since the occupation of the biome for cleaning pastures, preparing for planting and burning bagasse. However, this practice has also been used for deforestation of natural vegetation to incorporate agricultural activities. Thus, this work focused on analyzing the spatiotemporal distribution of fires in the Cerrado between 1999 and 2018, in order to evaluate the hypothesis that relates the incidence of fires to the increase in deforestation and the implementation of agricultural activities. For this purpose, the vector files of fire spots made available by the Fire Database (BDQ/INPE) were compiled, organized and processed in a GIS environment. After analyzing the variation of fires, according to the spatial cutout of the Biome and the Brazilian Federative Units and the annual, seasonal and monthly temporal distribution scales the fire spots were quantified according to the micro-regions defined by the Brazilian Institute of Geography (IBGE), Conservation Units, Indigenous Lands and Traditional Communities to assess their spatial occurrence. Likewise, statistical techniques were used to assess spatial autocorrelation, and spatial patterns and temporal trends in incidence, in these last two cases, using the Emerging Hot Spot Analysis technique. Lastly, the fire spots were intercepted by annual land cover and land use mapping, from the Mapbiomas Project, to verify the incidence of fire in the biome according to the types of land use and cover. In average terms, 65,523 annual fire spots were observed in the Cerrado reaching the maximum value of 137,918 fire spots, as registered in 2007. A clear concentration can be seen temporal in the quarter August-September-October (which correspond for 72% of annual occurrences) and high concentration, spatial association and increasing trend of fires in the states of Maranhão, Tocantins, Piauí and Bahia in a region known as MATOPIBA and also in the state of Mato Grosso, next to the Arc of Deforestation - both regions recognized as agricultural frontiers. At last attention is also drawn to the formations savanna and pasture are the land cover and land use classes with the highest incidence recorded, corroborating the initial hypothesis that fires have been routinely used for maintenance and implementation of agricultural activities.