Temporal Variation of Urban Areas and Natural Vegetation – Rio Turvo Watershed
ISBN 978-85-88783-11-9
Authors
1Fonseca Neto, F.; 2Castro de Oliveira, G.; 3Lopes Braga Fonseca, A.; 4Fernandes Filho, E.I.; 5Gripp Junior, J.; 6Alves Nascimento, L.
1UFV Email: franciscogeoifes@gmail.com
2UFV Email: guilhermecastrol86@gmail.com
3UFV Email: alebragaifes@gmail.com
4UFV Email: elpidio@ufv.br
5UFV Email: jgripp@ufv .br
6UFV Email: lecio.nascimento@ufv.br
Abstract
Among the various protected areas in Brazil are the permanent preservation areas (APPs) on hilltops. The New Forest Code (Law n 12651/2012) established new parameters for defining these areas. In this sense, it is necessary to develop a new procedure in Geographic Information Systems (GIS) that allows the mapping of these. In this context, this study aims to compare the variation temporal urban areas and vegetation cover in the Rio Turvo Watershed in Minas Gerais - Brazil. This paper aims to describe a methodology developed in ArcGIS 10 (ESRI, 2010) environment, which can be employed on any digital elevation model (DEM). Temporal classification of multispectral digital images of the sensor TM (Thematic Mapper) and OLI (Operational Land Imager), respectively, the Landsat 5 and Landsat 8 for the years 1985 and 2013 was used. For the implementation of image classification, two reference images was used. The first reference image, digitalization of homogeneous polygons were generated from samples collected up digitizing polygons on screen about the classes of interest in the image that capture samples that are more homogeneous. The second reference image, neighborhood operation was generated from the reference image by Scan-homogeous polygons, using the standard deviation of the digital pixel level with their neighbors, Focal statistcs Tool - ArcGIS 10.2. The accuracy of the classifier using the kappa index was assessed. The methodology neighborhood operation compared with the digitization of polygons, for the acquisition of training samples and improved the performance of the classification given by the Kappa index, it reached values higher than 0.9. Considerations were made regarding the alterations of the permanent preservation, according to the Forest Code currently in vigor, throughout these 28 years and can relate to the economic and social dynamics. For the delimitation of areas of analysis within the watershed was used shape files containing hydrography, the area of analysis (limits of the basin) and springs. The Digital Elevation Model was used for delineation of hillsides and hilltops. An increase of 73% of the area of forest in the Rio Turvo Watershed between the years 1985 and 2013, from 15.884ha to 27.491ha. The APPs were successfully delineated with the application of the model generated. The largest increase occurred in APPs into waterways, where areas of forest in 1985 and occupied in 2013 occupied 678.78ha 2073.24ha, representing an increase of 205.43%. In the upper third of the areas legally defined as "hills" there was an increase of 30.78% in the area covered by forests, from 1028.88ha in 1985 to 1345.5ha in 2013. An increase of forested areas and urban areas on steeper reliefs, while in the grazing areas were reduced at these locations. In general, urban areas increased from 4887ha to 7471ha, an increase of 52.87%. Places where there was greater expansion of these areas were those with a strongly undulating wavy as well as the springs of APPs. Contrary to what was expected, there was a relative increase of APPs in urban areas of rivers. The occupation of these areas were already established in the year 1985 and what happened, in fact, was a change in the pattern of occupation. Urban areas showed increases in steeper areas and on mountain tops. APPs springs were also occupied by urbanization. While urban sprawl has increased, there was no intervention in the areas of forest for its expansion. This is because the areas previously used as pasture were converted into new urbanized areas. Keywords: protected areas, forest code, APP