Dinâmica de ocupação no bioma cerrado: caracterização dos desmatamentos e análise das frentes de expansão

Abstract

This research aims to depict the human occupation process in the Cerrado biome throughout a semi-automatic land use characterization method in newly deforested areas, in two classes: "pasture" and "agriculture". To perform this, we used remote sensing techniques, including the analysis of the product MOD13Q1/EVI (Enhanced Vegetation Index) from MODIS dataset and alerts of deforestation obtained by SIAD - Cerrado. The use of GIS techniques, combined with theoretical models of occupation in the Cerrado region, allowed the identification of areas of agricultural frontiers. Based on this classification of deforestation events, occurred in the period 2004/2005 and 2006/2007, the method shows that 80% of deforestation in Cerrado are intended for expansion of grazing areas, while the remaining 20% are destined for agriculture. In relation to the area of deforestation, those events directed for pastures present an average of 1.5 km², while for agriculture the average area is 2.5 km², indicating purposes and different forms of intervention in the field. In the first period (2004/2005), the total area of the polygons occupied by agriculture totaled 1,263 km², while the sequent period (2006/2007) summed 971 km². About the deforestation destined for grazing, the total area was 3,316 km² in the period 2004/2005, while in the following period (2006/2007) it reached 2,918 km². Regarding the resulting maps, it was possible to understand the current dynamics of the agricultural frontier in the biome. This border zone represents the western of Bahia state, through the southcentral region of Piauí state, reaching the extreme south of Maranhão state in 2006/2007 period. Thus, our results indicate a clear tendency of expansion of the agricultural frontier into northern Cerrado biome.