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| Author(s): |
Laís de Carvalho Hanada
Total Authors: 1
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| Document type: | Master's Dissertation |
| Press: | Piracicaba. |
| Institution: | Universidade de São Paulo (USP). Escola Superior de Agricultura Luiz de Queiroz (ESALA/BC) |
| Defense date: | 2004-10-07 |
| Advisor: | Maria Victoria Ramos Ballester |
| Abstract | |
The Amazonian basin presents the biggest continuous area of tropical rain forest in the world, with an approach extension of 7 million km2, the biggest area located in Brazilian territory (67.8%). With all this extension this region presents distinct geomorphologic and climatic characteristics. The Brazilian portion of the Amazônia, known as Brazilian Legal Amazônia, comes passing for some transformation of its vegetal covering in the three last decades. This process is the result of a complex product of the implementation of infrastructure, economic factors, governmental politics, of ambient and cultural characteristics, resulting in high taxes of deforestation. Land use and land cover change can affect diverse ecological processes as, for example, biodiversity, the cycles of nutrients, cycle of water, among others. The Ji-Paraná basin is located in the State of Rondônia, is a typical example of this standard of deforestation in the Amazônia occidental. This region was object of the installation of the main programs of settling of the Federal Government from the decade of 70 and concentrates, currently, more than 60% of the rodoniense population. A spatiotemporal variation in land cover was produced (1986, 1992, 1996 and 2001) on the basis of the digital classification of images of Landsat-7 satellite, sensor ETM+ and Landsat-5, sensors. With intention to understand the influence of some drives of tropical deforestation like soil fertility, roads distance and setllements in the basin were carried through the geographic analysis of the factors in question for cross tabulation, and calculated Landscape Index (percentage area, average size of patchs and density of edge) for the characterization in the different resultant regions of the cross tabulation. The results of the analysis of land use and land cover change had shown that basin lost 15,313 km2 (20%) of the original forest. About regrowth areas was observed one of reuses of the same ones, pointing a trend of the State not to possess many areas in regeneration in more advanced stadiums (above of 15 years). The projects of settling, the soil fertility and distance of the main roads been significant factors to explain the dynamics of the deforestation in the basin. The agricultural areas for agricultural were located, mainly, in rich soils, being only 3,6% of these in regions with low soil fertility. The landscape metric showed an inversion of the matrix to the long one of the time. The regions that had suffered this conversion first are in regions located to a distance of up to 15 km of the main roads, showing the influence of the same ones in the process of matrix conversion. The regions that had presented low soil fertility, not taking in consideration the factor road, the first one was composed for native vegetation until the year of 2001. (AU) | |