The Impact of Deforetation in the Brazilian Amazonia : Change on Ecosystem and Social Environment

Most part of the world's tropical forest is located in the developing countries, and conversion is spreading each year. Colonization project is also advancing in the Brazilian Amazonia, and forests are converted at an average rate of 2l,000 km^2 /year. The purpose of this thesis was to examine how recent large-scale clearance affected the regional climate, environment and local people, and make suggestions for preserving the Amazonian fragile ecosystem. The present study dealt with hydrological analysis in Rondônia State, a remote region that accomplished a very fast development in the last two decades. A multi-temporal hydrological data of ANEEL were used for the water balance method, to find the effects of deforestation on water regime within developed and non-developed catchments. Land-uses were analyzed using the Landsat5 TM imagery processed by INPE. As a result of hydrological data analysis of small catchments in Rondônia State, runoff ratio increase of 0,15 to 0.5, evapotranspiration decrease of 1500 to 1000 mm and precipitation decrease of 2000 to1500 mm were observed in the developed area of Ariquemes, Jiparaná and Tabajara. On the other hand, high rate of evapotranspiration was observed in undisturbed catchment, in Pedras Negras. Rondônia State was one of the most remote regions of Legal Amazonia, however, this state suffered a large-scale clearance in the last decades,with the implementation of Brazilian development projects, specially in the late1970's. This fact was refleted in the hydrologic analysis. In developed cachment of Tabajara, evapotranspiration was up to 1000 mm till1980, however it decreased to an average of 700 mm since 198l. This figure indicated that the vegetation map of this area was altered from rainforest to savanna. Also, hydrologlcal analysis registered the runoff rate of 0.3 to 0.5, thus reflecting the result obtained from the remote sensimg analysis, registering 30 to 50% clearing in that region. As for the Brazilian government policy, concerned with the preservation of the Amazonian rainforest, zoning strategy was implemented, in order to make a clear division for land-uses, thus preserving the fragile tropical ecosystem and protecting local people's life. The field study was carried out in three districts among 6 zones, to examine the real function of that strategy. As a result, in a farmland of the Jiparaná’s colonization project, the rule for 50% clearing was not obeyed, and in Karitiana village, intrusion was still common. As for the Amazonian local people, Karitiana village was visited in Rondônia State, in order to examine their traditional lifestyle and problems faced by the Karitiana people. As a result of the field study in Karitiana village, it could be noted that development was affecting their lifestyle. The Karitiana people suffered an abrupt decrease of its population from 5000 to 12 people in the early 1970's, due to the deveiopment projects implemented in Rondônia State, in the last decades. In August 1997, they were 207 people, 11 from other ethnic groups and 24 1iving in the House of Indios, in Porto Velho. There were few old people and 70% of them were composed of children. Two or three of them were dying every year, contracting diseases brought by the white people, and there were many sick people in the House of lndios in Porto Velho, without proper doctor care. Health assistance, transport means and education were the first aid they needed. Finally, the main goal of this paper was to make clear the current forest situation of the Brazilian Amazonia to find better method for decision making on land-uses and forestry in order to satisfy both local people subsistence and global needs concerned with the sustainability of the ecosystem. As a whole, the Brazillian Amazonia presented many negative influences of development. Zoning strategy should function properly to allow the conservation of ecosystem. In order to accomplish that purpose, financial aid in academic activities