Dinâmica Espaço Temporal da Cobertura da Terra em uma Bacia Hidrográfica da Região do MATOPIBA, Brasil

Abstract

The expansion of agricultural and pasture frontier in the Brazilian Cerrado has already led to the loss of 46% of its original vegetation cover since the beginning of the 1980sThis fact caused significant fragmentation of the natural landscape, being the region of MATOPIBA (Maranhão, Tocantins, Piauí and Bahia states) directly related to this expansion. Monitoring land use and land cover from remote sensing data and geoprocessing tools can contribute to understand the deforestation dynamics in this region. Thus, the goal of this study was to analyze the space-temporal dynamics of land use and land cover for the Rio Corrente basin, located in the territory of MATOPIBA, specifically to the south of Piauí. In this study, we used images from Landsat-5 Thematic Mapper (TM) e Landsat-8 Operational Land Imager (OLI) satellites for the years 1986, 1996, 2006, and 2016 and we performed a supervised classification for these years using the Maximum Likelihood Algorithm (Maxver), in QGIS 2.14.3. The classification had the accuracy assessment using the Kappa Index. Between 1986 and 2016, the Mata Ciliar/Cerradão class was reduced 39.54 km² (9.1%). The Cerrado Denso/Cerrado Ralo class reduced 129.71 km², corresponding to 47.8% less than the 1986 cover of this class. At the same time there was a significant increase in the categories of Bared Soil and Agriculture/Pasture, being 43.5% and 333%, respectively. The supervised classification showed a very good agreement, ranging from 0.91 to 0.96. The results obtained call attention to the progress of agricultural activities in the MATOPIBA region, requiring greater attention from soil managers and stakeholders, as well as Brazilian environmental protection agencies.