Monitoring desertification in semiarid Brazil: Using the Desertification Degree Index (DDI)

Abstract

Desertification is a phenomenon that takes place in the arid, semiarid and dry subhumid areas of the Planet. Although its causes and consequences are well known, data and robust information are often insufficient to provide indicators that allow desertification effects to be measured precisely and efficiently. Accordingly, the objective of this study was to introduce a methodology for the drafting of a monitoring index for desertification, with indicators of vegetal coverage, taking the semiarid area of Paraiba State, Brazil, as the test example. For this purpose, we analyzed conserved and desertified areas (22 pairs), in which we evaluated the following parameters: woody species richness, woody plant density, canopy height, mean basal circumference, mean circumference at breast height and total absolute dominance. First, we selected the indicators, calculated the areas of coverage and measured the reference values. Subsequently, we obtained masses for the indicators, and developed and tested the desertification degree index (DDI). The DDI showed 99% accuracy and 95% efficiency, respectively, and was able to select indicators and evaluate the level of desertification in the test areas. The methodology is simple, inexpensive and replicable in other regions of the world as a means of monitoring and planning strategies to counter desertification.