Produção Nacional
Detection and geographical distribution of clearing areas in the savannas ('lavrado' ) of Roraima using Google Earth web tool
2011; Academic Journals; Volume: 4; Issue: 3 Linguagem: Inglês
10.5897/jgrp.9000038
ISSN2070-1845
AutoresReinaldo Imbrózio Barbosa, Ciro Campos,
Tópico(s)Geography and Environmental Studies
ResumoThe objective of this study was to detect clearing (anthropogenic disturbance) and evaluate the geographical distribution of different land uses in the savannas (lavrado) of Roraima, Brazilian Amazonia. Data were obtained from visual interpretation of very high (Ikonos and QuickBird - 2001 to 2007) to high (Landsat TruEarth® - Mosaic 1999 to 2002) resolution images offered by Google EarthTM application version 5.1.3533.1731. The visual interpretation resulted in the generation of polygons representing land use categories including information on land use change (natural to anthropogenic). Spatial analysis was conducted and the polygons corresponding to different land use categories were juxtaposed with thematic layers of municipality divisions, limits of protected and indigenous lands. 42,706 km2 were defined as ‘lavrado’. Of this total, 1986.7 km2 (4.65%) were consideredanthropogenic disturbed areas: 17.8% in forest (alluvial and contact) and 82.2% in non-forest (savannas) ecosystems. The majority of land cleared occurred in unprotected areas (81.46%), while “indigenous lands“(18.53%) and “protected areas” (0.01%) represented smaller portions of the total area. Shifting cultivation (seasonal agriculture or crop rotation) in non-forested systems (611.32 km2) was the land use most observed (30.8%). Our geographical data suggest that anthropogenic land use in the ‘lavrado’ has a pattern of distribution associated with close to roads that cross the capital of Roraima, Boa Vista. Key words: Savanna, lavrado, cerrado, Amazonia, land use.
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