Análise de risco ecológico sobre os sistemas aquáticos na bacia do Rio Tenente Amaral em Jaciara-MT com ênfase na atividade agropecuária

• Autor(a) principal: Castanha, Márcio
• Data de Publicação: 2012
• Tipo de documento: Dissertação
• Idioma: por
• Título da fonte: Repositório Institucional da UFMT
• Texto Completo: http://ri.ufmt.br/handle/1/1288
• topic: Sensibilidade; Risco ecológico; Unidades hidrológicas; CNPQ::CIENCIAS HUMANAS::GEOGRAFIA; Sensibility; Ecological risk; Hydrological units

Risk evaluation was integrated with principles of landscape ecology and allows the identification of how much does human activities damage the ecological integrity. So, this research aims to evaluate the ecological risks generated from agriculture and pasture that damage the ecological integrity in the drainage-basin of Tenente Amaral/MT. The stressors were studied by hydrographic units of the referred basin, these units being created through numerical models of the terrain. In order to understand the spatial distribution of these stressors, a mapping of land use based on fuzzy logic was used. The generation of sensitivity maps for landscape units by stressor was based on the physical variables of terrain, climate, steepness and hydrologic units systems. Among the steps in the elaboration of the risk index, it was taken into account the severity, that is the potential damage of each threat to the components of ecological integrity: water quality of the habitat, biotic interactions, flow regime and energy sources. Both severity and sensibility were measured by specialists who attributed the degree of low, moderate or high to each of these components to each stressor. The quantification and attribution of frequency classes of each stressor was made considering it's percentual in area and the number of occurrences in the 51 drainage sub-basins. The ERI (Ecological Risk Index) was applied for each stressor on each sub-basin using the results of the previous informations generating a map, on the aproximate scale of 1:100.000 that shows from very low to very high degrees of risk of each of the stressors by sub-basin. In this research, the results showed that the sensibility was higher to the stressor pasture, around 27% of sub-basins were deemed highly sensible, while for agriculture 17% showed high cumulative sensibility. As for the ecological risk result, more than 39% of the drainage-basin of the Tenente Amaral river showed very high and high levels, indicating it's vulnerability.