Utilização de imagens Landsat5 (TM) para o mapeamento e monitoramento de pastagens em 33 municípios no Sudeste do Pará

The Brazilian livestock has been suffering pressure from national and international entities regarding the occupation of land with pasture. Thus, the government has created a program to map and monitor the advance of livestock in the state of Pará through geoprocessing and remote sensing techniques. The aim is to portray the occupation and monitor the increase of pasture areas annually, through satellite imagery, providing better orientation on audits performed by governmental agencies in the areas of pasture expansion. Mapping and monitoring have been done by the use of Landsat5 (TM) satellite images in 33 municipalities of the southeast of Pará state. The analysis consisted of image interpretation to determine polygons of pasture areas, using software for image processing and cartographic edition. It was found that 30.5% of the mapped area was occupied by livestock in 2011. The monitoring of 2011 showed an increase of 2.4% of deforestation compared to the year 2010. This result showed that satellite imagery mapping is a tool that supports the analysis of the Brazilian livestock scenario and monitoring is a tool that safely quantifies the areas that are being deforested for this activity. This paper contributes to the defining of policies to reduce deforestation such as an appropriate use of pastures and management of animals with effective techniques. The adoption of such policies result in the increase of beef cattle productivity and the decrease of environmental problems such as erosion and desertification,consequently avoiding the opening of new areas of pasture on forested areas.Pages: 7578-758

Mapeamento e monitoramento de pastagens no Sudeste do Pará

Brazilian cattles breeding has had a negative evaluation, by environment entities, due to the extension of land occupied with pasture. To answer questions in this context, the Ministry of Agriculture determined the establishment of a program with the objective of describing the current situation and of carrying out an annual monitoring of the expansion of pasture areas. The results should ensure more effective scrutiny in the audits made by the official entities responsible for these areas. In the second semester of 2009, a pilot area, covering 6 counties in the Southeast of Pará state, was mapped and, in 2010, this area was monitored with the purpose of identifying possible expansion of pasture land in this year. The mapping and the monitoring were realized with Landsat5(TM) images. The work consisted in the analysis and interpretation of images to determine the polygons of pasture areas, using software of image processing and cartographic edition. It was found that 23% of the region that was mapped in 2009 was farmland, 98.4% of which are occupied by livestock, and 1.6% is cultivations. The monitoring findings in 2010 indicated an increase of 3% in the pasture areas in relation to 2009. This makes it succeeded in establishing a trustworthy quantification of the areas that are being deforested to give place to cattle raising activities; thus, providing data that will help set up governmental actions to inhibit the negative impact caused by these activities.Pages: 169-17