Modelagem da paisagem da Floresta Estacional Decidual no Vão do Paranã, Goiás
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2010-12-10
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Universidade Federal de Goiás
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Current dry forests in the Vão do Paranã region, northeastern Goiás State, Brazil, are strongly fragmented mainly because of intense cattle ranching activities. This affects the ecological dynamics of flora and fauna since the connectivity among remaining fragments is reduced. The objectives of this study was: a) to map dry forests occurrences in the study area; b) to determine the relevant geoenvironmental indicators that control dry forest occurrences in the landscape; c) to find areas with high pressure in terms of human occupation of remaining fragments; and d) to propose an operational strategy for dry forest conservation. The map of dry forest occurrences was obtained from the image interpretation of multitemporal LANDSAT satellite scenes. The environmental controllers analyzed were climate, topography, geology and soils. The human occupation pressure in the remaining fragments was analyzed based on the metrics obtained from land use and
land cover map, environmental data and social and economical data. The proposal for conservation strategy of dry forests was based on the idea of using tree species such as the Aroeira (Myracroduon urundeuva) found in cultivated pastures as living
fences before they are cut as invasors by the farmers.
Results indicated the presence of approximately 190,000 hectares of dry forests in the study area. The largest fragments were mostly found in the central and northern parts of Vão do Paranã. It was found that there was a strong relationship between lithology (carbonatic rocks) and the presence of dry forests, both in plain areas and in rocky outcrops. A detailed qualitative analysis indicated the main controls for the
establishment of the dry forests: strong water table variation in the soil-bedrock profile, the soil eutrofism and the climatic seasonality, allowing a hierarchy that can be described as: strong water table variation in the soil-bedrock profile > soil
eutrofism > lithology > climatic seasonality > rainfall > soils > hipsometry > slope. As the most remaining fragments are located in hilly areas with limestone outcrops, only 1% presented high and very high tendencies for land occupation, though they are facing strong wood selective loggings. The substitution of dead fences for living fences and the increment of isolated trees indicated an increase of permeability of
matriz and of conectivity among remaining vegetation fragments. The simulation of a scenery based on three test sites indicated that such substitution would result, for the
entire Vao do Paranã region, in 338,520 trees saved (4.2 km2) and 5,077,800 new trees planted in form of living fences (63,5 km2). Regarding isolated trees, in the case of all pasture areas present an average of 310 trees per km2, this would represent 42 km2 of vegetation cover.
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HERMUCHE, Potira Meirelles. Modelling landscape of seasonal decidual forest form Vao do Parana Valley, State of Goias. 2010. 137 f. Tese (Doutorado em Ciências Agrárias) - Universidade Federal de Goiás, Goiânia, 2010.