TEMPORAL EVOLUTION OF DEFORESTATION IN THE WATERSHED OF THE ESTIVA RIVER, BRAZIL - DOI: 10.13083/1414-3984/reveng.v23n4p363-370

Abstract

The watershed of the Estiva river (3,009.00 km2), a tributary of Uruçuí-Preto river located in the state of Piauí, Brazil, is undergoing a process of deforestation to opening new areas for soybean cultivation, which may be one of the practices that most causes environmental impacts in the region. Thus, the present work sought to analyze the temporal evolution of land use in the watershed of the Estiva river between the years of 1984 to 2010. Six satellite images of the TM sensor on the Landsat 5 satellite were used from years 1984, 1990 1996, 2003, 2006 and 2010. First the images were pre-processed for contrast and geometric corrections. After the initial corrections the images were classified according to an automatic supervised method using the Maximum Likelihood algorithm. The results showed there was an increase of 272.41% (658.26 km2) in land use and occupancy of soil by crops and a consequent advance in deforestation of 30.01% (686.50 km2) in the Cerrado areas and 24.60% of all native forest areas in the Estiva river watershed between the years 1984 to 2010. A total of approximately 680 km2 of the Cerrado area was deforested between 1984 to 2010 for the implementation of crops in the Estiva river watershed.