Fragmentação florestal, dinâmica e ecologia da paisagem na bacia hidrográfica do rio Itapemirim, ES. / Forest and dynamic fragmentation of landscape ecology on the Itapemirim river hydrographic basin, ES.

AUTOR(ES)
FONTE

IBICT - Instituto Brasileiro de Informação em Ciência e Tecnologia

DATA DE PUBLICAÇÃO

26/03/2010

RESUMO

This study had as the most important objective to analyze the structure of forest landscape on the Itapemirim ES basin river, using quantitative methods with indexes of landscape ecology, aiming the selection of suitable areas for environmental conservation; and to study the influence of the edge effect on the different sizes of these fragments. Initially the mapping of the forest fragments was obtained of all representative area of the Itapemirim river basin and the indexes analysis of landscape ecology for three size classes of fragments was made, where the ones considered small were those which area was lower than 5 ha, average those which area between 5 and 50 ha and large fragments all those with area larger than 50 ha. For the calculation of the metrics of landscape ecology the extension Patch Analyst was used within the computational application ArcGis 9.3. In general 3285 forest fragments were found in all the area, representing 17% of forest covering. Quantitative characterizations through landscape metrics were made with groups of area index, density and size, shape, proximity and nuclear area, the latter obtained for different simulations of edge effect (20, 40, 60, 80, 100, 140 and 200 m). For all indexes there were differentiations about the size classes of the forest fragments, indicating that the larger fragments showed results of landscape metrics that indicated a higher degree of conservation than the smaller fragments. Then mapping of land use for the years 1970 and 2007 was performed in the vicinity of two preservation areas present in the study area, the Private Reserve of Natural Heritage Cafundó and the National Forest of Pacotuba. Through the land use map of the two selected dates, we could analyze the changes which occurred in the surrounding landscape of preservation areas, quantifying the landscape structure through metrics for the years 1970 and 2007. Over the 37 evaluated years there was little change in the use and occupancy of the land surrounding the units, where the two areas are dominated mostly by grazing. Metrics or indexes of landscape ecology were obtained through the extension Patch Analyst at landscape and class level, and values for the 10 classes of use and occupancy of land mapped were obtained. The results of quantitative analysis by metrics pointed to an increase in fragmentation of the landscape surrounding the Units of Conservation RPPN Cafundó and FLONA of Pacotuba

ASSUNTO(S)

Índices de ecologia da paisagem uso da terra patch analyst indexes of landscape ecology land use forest fragments fragmentos florestais florestamento e reflorestamento patch analyst

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