A efetividade do Refúgio de Vida Silvestre Veredas do Oeste Baiano frente ao avanço da fronteira agrícola MATOPIBA
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2017-10-02
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Universidade Federal de Goiás
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The protection of natural resources by the creation of Protected Areas (PAs) has been implemented in Brazil with relative success, allowing a significant diversity of framing between integral protection and sustainable use. The effectiveness of these protected areas is determined by the social actors involved in the unit and its surroundings. Only in the Cerrado, there are 386 protected areas covering the entire biome in different socio-economic and environmental contexts. The northern portion of this biome is under intense pressure for the intensification of the conversion of the Cerrado by agribusiness, which has been enhanced since the creation of the MATOPIBA region. In the western Bahia Plateau, this expansion has been specifically polarized by the municipalities of Luiz Eduardo Magalhães and Barreiras, and has been intensified in the last 15 years with the consolidation of irrigation projects by central pivots. In 2000, the federal government created the Refugio de Vida Silvestre Veredas do Oeste Baiano (RVSVOB) in this region to fully protect a habitat of the loon duck (Mergus octosetaceus). Its geographic boundaries follow roughly the layout of the enclosed valley of the Pratudinho River and the high valley of the Pratudão River, including, at its extreme east, a part of dissected hills. Despite being protected, the area and its ecological function have suffered from the impacts of anthropogenic pressures from the plateaus (exploitation of water for the projects and central-pivot installation, e.g.) and in the enclosed valleys (burnings, grazing, accelerated erosion, e.g.). Due to these problems and the strict relation that the UC has with the superficial water resources, the effectiveness of the RVSVOB can be put in checkmate. In this context, it is proposed to evaluate the effectiveness of this PA through of the analysis and modeling of analogous space-time environmental systems. Therefore, the adjacent watersheds were chosen in the north - Veredãozinho River - and in the south - the Formoso River - whereas similar areas to the RVSVOB were delineated for comparative analysis of the most important elements and flows in the ecological function of this PA. The analysis units adopted were: (i) watershed, (ii) watershed segments (high, medium and low), (iii) RVSVOB and its similar areas. The elements and flows analyzed were (i) change of land use and cover, (ii) installation of central pivots, (iii) river channel flow, (iv) physical and chemical aspects of canal water fluvial. The river waters were sampled twice (end of rainy and dry seasons) in three points along each channel (Rios Veredãozinho, Pratudinho and Formoso) in the hydrological year 2015-2016. The elements related to land use were obtained by the interpretation of maps generated by a time series classification (1970, 1980, 1990, 2000, 2010 and 2016) satellite images from Landsat (5, 7 and 8) and the other data obtained from public agencies. The results indicate that, in general, the three basins are inserted in the same context of succession of use and land cover, following the trend of what happens around the Chapada do Oeste Baiano. In the 1970s, 1980s and 1990s, the savanna formation burned for the pioneer occupation of livestock and forestry, while agriculture still occupied small stretches of the valleys. From 2000 on, the area of agriculture grows exponentially and gains space over areas of forestry and savanna formations and abandons the valleys. Specifically, RVSVOB and its analogous areas have similar succession of cover and land use up to the creation of the PA in 2000, when, in the PA, the burnings and agriculture start to reduce exponentially. The installation of central pivots and the concession of water grants were also heterogeneous among the three analyzed basins, with a higher concentration in the upper and lower sectoin of the Formoso River basin and in the lower section of the Pratudinho River. The quality and quantity of water in the three sampling points in each basin do not have any significant difference in the measured values, showing, in general, low concentration of suspended load and turbidity and high dissolved oxygen. The evaluation of the effectiveness of RVSVOB allows verifying that, on the one hand, the unit has contributed to the conservation of the Cerrado within its territory - recovering deforested and burned areas and, on the other hand, the quality and quantity of water resources is independent of the existence of RVSVOB, being similar in the nine monitored stretches. This similarity allows affirming that the quality of the water resources is good in all points, however, the lack of flow data prior to the superficial and underground grants does not allow evaluating if there is loss in the amount of water in the channels. This framework shows that, on the one hand, the Refugio de Vida Silvestre Veredas do Oeste Baiano has fulfilled its ecological function, ensuring the quality of natural resources, on the other, the expansion of agribusiness occupies preferably the areas of the highlands and plateaus not pressing the dynamic of enclosed valleys but indirectly.
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PÔSSAS, I. B. A efetividade do Refúgio de Vida Silvestre Veredas do Oeste Baiano frente ao avanço da fronteira agrícola MATOPIBA. 2017. 133 f. Dissertação (Mestrado em Geografia) - Universidade Federal de Goiás, Goiânia, 2017.