Avaliação de Indicadores Biofísicos de degradação/desertificação no núcleo de São Raimundo Nonato, Piauí, Brasil

Abstract

The desertification process, a type of environmental degradation that devastates the arid, semi-arid and dry sub-humid regions of the globe, has causes and consequences that are complex. Among the causes, we can highlight the climatic variations of natural and/or antropic order. One of the direct results of these climatic variations is observed from the vegetal coverage reduction, that unleashes and/or accelerates the erosion of the soils, and at the last instance, culminates in the process of desertification. The complexity of this process requires the employment of an integrated approach. A set of climatic, morphopedological and biotic indicators was employed, with the objective of achieving the risk analysis of the degradation/desertification of the semi-arid nucleus of São Raimundo Nonato (PI). These indicators were combined with the utilization of IDRISI 3.2.2 information System. The analysis that was realized, considering the years of 1987 and 2007, indicates a reduction of degradation/desertification of the studied area. In 1987, a distribution in the classes of average degradation/desertification was of 70% and 30% in the high class. These values were, in 2007, equal to 71% and 29%, respectively, which appears to characterize a situation of dynamic equilibrium of the studied area.