Modificações espaço-temporais na paisagem da bacia hidrográfica do rio Peixe-boi, mesorregião nordeste paraense.

Abstract

The northeast mesoregion of state of Pará, in Brazil, is an example of region that suffered a disorderly occupation process, since this territory is one of the first colonization areas within the Brazilian Amazon . The occupation process in this region has more intensely developed after the Bragança‟s rail Road consolidation, and therefore, causing significative social and economic changes in this area, but also inducing the interest of several scientific studies since then. In this context, the present work seeks to spatially evaluate the Spatio-temporal changes of landscape in the Rio Peixe-Boi drainage basin, during a period of twentyfour years of occupation in the northeast mesoregion of the state of Pará, using remote sensing and geoprocessing techniques and integrated products. An identification about the occupation process in this region was made aiming to incorporate this knowledge to the land use and cover change detected and quantified through Landsat TM/5 sattelite imagery. The images analyzed are related to the years of 1984, 1996,2004 e 2008. The ArcGIS 10 and ENVI 4.5 softwares were used in this work for a non-supervised clustering followed by a supervised one, resulting in the identification of three main land cover classes (Ombrophilous dense forest, secondary successional vegetation and natural fields), three land use classes (Agriculture/Reforestation, Pasture, Exposed soil) and three additional classes (water, shadow and cloud). The landscape analysis results shown that the secondary successional vegetation class is dominant in the landscape and that the pastures represent the dominant pattern in land use cover. While the cattle ranching is in remarkable expansion, the Agriculture/Reforestation class has shown a small expressivity regarding its occupation area The analyses of the landscape dynamics implies that major stability was verified in the Ombrophilous dense forest class, although there is a great anthropic pressure in the Rio Peixe Boi drainage basin, mainly associated to the cattle expansion areas.