Estratificação e caracterização ambiental da Área de Preservação Permanente do rio Guandu, RJ

Abstract

The Permanent Preservation Areas (APP) is a riparian forest, although protected by the actual legislation for, are devastated in Brazil. Its preservation is very important for hydric resources conservation. The Guandu River is the main water provision source in Rio de Janeiro metropolitan area, assisting a population about nine million people. Although this, the river has serious environmental problems now. This study objectived to do an environmental characterization in APP of Guandu River, Rio de Janeiro State, Brazil, through digital aerial photographs, to describe the existent environments along the river and its degradation degree. The aerial photographs were obtained with a digital photographic camera of small format, in a flight on the river. The images were contained in mosaics, processed with the use of ArcMap 9.0 and ArcView 3.2a. The degradation degree map of each environment of Guandu River was based in land use, urban-industrial and native vegetation proximity maps. Two forest fragments were chosen for a floristic and plant sociology studies. Ten land use classes and four different environments were defined on APP: Environment 1 (fitted valley), Environment 2 (floods), Environment 3 (aluvionar plain), Environment 4 (marine influenced). In general, the land uses that prevailed were pasture and agriculture. The Environment 4 was considered the more impacted, presenting 51% of its area with high to very high degradation degree, and the Environment 3 presented a better conservation state in comparison with the others. The forest fragments represented only 11,6% of total APP, and they presented very reduced sizes. The most common species in area were Guarea guidonia, Peltophorum dubium and Casearia decandra. These results suggest that the cultivations and pastures predominance, the urban centers proximity and area very reduced forest, can damage the quality of this important water source.