Avaliação Da Cobertura Florestal Na Paisagem De Mata Atlântica No Ano De 2010, Na Região De Ouro Preto - Mg

Abstract

RESUMO:Objetivou-se, neste trabalho, avaliar o estado de conservação atual da paisagem na região de Ouro Preto, Ouro Branco e Mariana, MG, correspondendo à áreas situadas no alto das bacias dos rios das Velhas, do Carmo, Gualaxo do Sul e ribeirão da Colônia. A região possui diferentes Unidades de Conservação (UCs), localizadas no domínio fitogeográfico da Mata Atlântica. Utilizaram-se imagens RapidEye AG (jun/2010) com 5 m de resolução espacial. A classificação do uso do solo para obtenção das métricas da paisagem foi dividida em três classes: Floresta Estacional Semidecidual Montana, Vegetação natural 2 e Uso Antrópico. Os resultados apontaram que a área de estudo encontra-se bem preservada, principalmente dentro das UCs, onde se localizam os grandes fragmentos, principais para a conservação; as formações naturais presentes na área de estudos corresponderam a 87,08%; as métricas mostraram que a distância média entre os fragmentos (262) é 72,18 m; a forma e o efeito de bordas nos fragmentos apresentaram-se adversas à preservação da biodiversidade; fortes pressões antrópicas: área urbana, solo exposto, minerações etc., estão presentes em maior intensidade fora da Zona de Amortecimento (ZA) do Parque Estadual do Itacolomi; pontos vulneráveis à conservação encontram-se, em grande parte, próximos às áreas de pastoreio e de mineração, com destaque para as áreas de campo das UCs de Ouro Branco e de pastoreio dentro da APA Estadual Cachoeira das Andorinhas. FOREST COVER EVALUATION IN THE ATLANTIC FOREST LANDSCAPE OF THE OURO PRETO REGION -MG, IN THE YEAR 2010ABSTRACT: This study aimed to evaluate the current state of conservation and the landscape connectivity in the area covering part of the counties of Ouro Preto, Mariana and Ouro Branco, MG. This area is located at the upper course of the Velhas river, Carmo river, Gualaxo do Sul river and Colônia creek. The region belongs to the Mata Atlantica phytogeographic ecosystem and encompasses different Conservation Units (CUs). RapidEye AG (Jun/2010) with 5 m of spatial resolution images were used. The study area was divided into three classes: Seasonal semideciduous montane forest; Natural vegetation 2; Anthropic use. The results showed that the study area is well preserved, particularly inside the CUs where the fragments are bigger and are considered priority sites for conservation. The natural formations of the region corresponded to 87.08% of the study area. The metrics showed that the average distance between the 262 fragments is 72.18 m. The shape of the fragments do not favor the preservation of biodiversity, because they are complex and irregular (fractal). The application of edge effects initially increases the fragmentation and, subsequently reduces the size of individual vegetation spots, smoothing their complex shapes. Strong anthropic pressures are present outside the buffer zone of the State Park of Itacolomi. The weak points are those surrounding pastoral and mining areas, mainly field areas of CUs in Ouro Branco and pasture areas inside the Cachoeira das An...

The Landscape of Ouro Preto (Mg, Brazil) Through Analysis of Anthropic Activities in Relation to the Environmental Conservation

“…In Figure 2 is shown the effectiveness of operating conservation units for the environment preservation In Figures 1 and 2 are shown the Ouro Preto landscape, where large apparently well-structured regions are observed in relation to existing vegetation cover, without major differences, as found by Silva et al (2015). However, further studies should be performed to increase knowledge about the quality and biodiversity of these forests, since it is known that the Uaimii Forest, which is partially in Weight 1, is a new forest in an advanced regeneration process after several decades of clearcutting in the region.…”

“…The classes of land use and land cover to be mapped were based on the most expressive land uses (SILVA et al, 2015): semi-deciduous seasonal forest montane; natural fields; field with rocky outcrop; water; urban area; eucalyptus; pasture; exposed soil; mining; and others. In order to aid the separability among the classes, the following distinguishing parameters were inserted: the average values of the reflectance of objects in different bands; the normalized difference vegetation index (NDVI); the brightness (average spectral value of an object considering all bands of the image); the ratio among bands; the brightness among bands; and the maximum difference (calculated by the difference of the minimum value of an object by its maximum value).…”

“…However, it still contributes largely to the degradation observed from the various levels of erosion present in the fields (SILVA et al, 2015). Tourism is very strong in the areas located in Weights 2 and 3; it is emphasized that its predominance occurs especially in areas where large mining decreases its influence.…”

Land use in Permanent Preservation Areas of Grande River (MG)

“…The field survey allowed the validation of the classification by the analysis of the confusion matrix and the Kappa coefficient Silva et al, 2015;Moreira et al, 2015). The confusion matrix shows the number of pixels correctly classified and the number of pixels estimated by the classification for each class (Oliveira et al, 2008(Oliveira et al, , 2013Reis et al, 2012).…”

“…Its occurrence causes loss of structural connectivity and induces fragmentation and extinction of forest remnants (Silva et al, 2015).…”