Fragilidade ambiental da Bacia Hidrográfica do Rio Perdizes (MG): Um estudo de caso para o planejamento agrossilvipastoril

Abstract

The preservation of ecosystems is the result of the morphogenetic conditions of the earth's natural systems and the process of human use and occupation of the earth, especially in landscapes altered by agricultural activities. The concept of Environmental Fragility is derived from the principles of ecodynamics proposed by Tricart (1977). It refers to a set of natural and anthropogenic factors. The case study was carried out in the Perdizes River Basin, in the Messoregion of Triângulo Mineiro and Alto Paranaíba, Minas Gerais. In this study, the following environmental variables were considered: soil type, relief dissection index, geomorphology, proximity to water bodies and slope for geospatial modeling and land use and land cover. Through the analysis of multiple criteria, different classes of Environmental Fragility were modeled: (i) very low, (ii) low, (iii) medium, (iv) strong and (v) very strong. Computed Environmental Fragility from Potential Fragility and Emerging Fragility. The area of the Perdizes river basin has deep soils which, together with a predominantly flat slope, favor the mechanization of agricultural areas. The relief dissection index predominates in the upper class, due to its very low average interfluvial dimension and high degree of valley carving. The geomorphology is predominantly in class 3, which presents a dissection with a convex and tabular top with deepening of the incisions up to 50m. The potential fragility analysis revealed that most of the study area is concentrated in classes 2 and 3, totaling 119,699.81 ha or 96.26% of the basin area. Regarding emerging fragility, most are in classes 3 and 4, together they add up to 108,637.25 ha, equivalent to 87.37%. The results indicated that potentially fragile areas tend to become more sensitive to human action. It is concluded, therefore, that anthropic actions affect environmental fragility when the area already has natural sensitivity, land use, and cover accentuate the fragility.