Socio-Environmental Vulnerability to Drought Conditions and Land Degradation: An Assessment in Two Northeastern Brazilian River Basins

Over the past few decades, a significant amount of agricultural land has been lost due to soil degradation/desertification. In addition, the increasing frequency of extreme events, such as intense droughts and forest fires, has negatively impacted various ecosystem services. Two of the main Brazilian biomes-the Cerrado and the Caatinga-have been affected by increased rainfall variability, leading to desertification, increased fire frequency, and, consequently, rising concerns regarding the water and food security of the local population. In this study, we develop a methodology to assess these impacts using a Socio-Environmental Vulnerability Index (SEVI) that combines physical, environmental, and socio-economic indicators related to exposure, sensitivity, and adaptation, as well as including socio-environmental feedback. The developed SEVI is then applied to the Sao Francisco and Parnaiba river basins. The proposed index is based on the MEDALUS methodology and is adapted to include multiple biological, physical, and socio-economic indicators, allowing for the discrimination of areas characterized by different levels of vulnerability. We also analyze the effectiveness of governmental policies, such as the creation of conservation areas and the rural registration of properties, in reducing vulnerability. The SEVI analysis highlights that adaptive capacity is the main constraint for reducing socio-environmental vulnerability in the Parnaiba basin, while exposure and sensitivity are the greater challenges in the Sao Francisco basin. The results of this study are crucial for the prioritization of recovery actions in degraded areas.

Automated summary

In the past few decades, the loss of agricultural land due to soil degradation/desertification has been significant. The increasing frequency of extreme events, such as droughts and forest fires, has negatively impacted ecosystem services. The Cerrado and Caatinga biomes in Brazil have been affected by increased rainfall variability, leading to desertification, increased fire frequency, and rising concerns about water and food security. This study develops a Socio-Environmental Vulnerability Index (SEVI) and applies it to the Sao Francisco and Parnaiba river basins to assess the impacts and prioritize recovery actions in degraded areas.