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.

Temporal analysis of desertification vulnerability in Northeast Brazil using Google Earth Engine

“…We used the Normalized Difference Vegetation Index (NDVI), which presents a strong correlation between the indicators in evaluating land surfaces and the vegetation cover in plant biomass evaluation (Figueira Branco et al., 2019; Sun et al., 2021; Veloso, Ferreira, Ferreira Júnior, & Barbosa da Silva, 2020). The Modified Soil‐Adjusted Vegetation Index (MSAVI) is a vegetation index used to characterize the high proportions of bare soil or the low concentration of photosynthetic pigments in plants caused by long dry periods which characterize landscape patterns, and the albedo of land surface is a measure of the solar radiation reflected from an object or target to the amount of incident energy, to characterize land surface micrometeorology (de Souza & Oyama, 2011; Jesus, Barros de Souza, Souza de Oliveira, & Gama, 2019; Sá, Cunha, Taura, & Drumond, 2015; Vendruscolo et al., 2020).…”

“…Considering this, we selected an indicator to represent an aspect of the land surface condition. We Souza de Oliveira, & Gama, 2019;Sá, Cunha, Taura, & Drumond, 2015;Vendruscolo et al, 2020).…”

“…Desertification causes and consequences are widely debated to observe how climate change is interfering in the vegetal composition of a region (Vendruscolo et al., 2020); understanding the occurrence patterns of this phenomenon is essential for monitoring and obtaining information based on case studies. In the northeast region of Brazil, the history of vegetation exploitation has always been associated with the conversion of these areas into agriculture and pasture, as well as the exploitation of its forest resources, without adequate planning and management.…”