Avaliação ecológica rápida e análise temporal das alterações no conteúdo de água em uma vereda do Ribeirão das Araras, Araguari, Minas Gerais

Abstract

Veredas are wetland savanna ecosystems characteristic of the Cerrado biome, recognized as Permanent Preservation Areas because they harbor springs and play a fundamental role in maintaining biodiversity, recharging aquifers, and regulating water flow within watersheds. However, these ecosystems exhibit low resilience to environmental disturbances and have been severely degraded by the expansion of human activities, compromising their structure and ecological functioning. In this context, this study aimed to evaluate the impacts of human-induced changes on water content across three sections of a vereda in the Ribeirão das Araras sub-basin (municipality of Araguari, Minas Gerais) over the past 40 years. To this end, Landsat imagery from 1985, 1990, 2000, 2010, 2020, and 2025 was processed using the Google Earth Engine platform to calculate the Normalized Difference Water Index (NDWI), enabling an analysis of moisture dynamics within the vereda areas. A Rapid Ecological Assessment (REA)—adapted for these environments—was also conducted to qualitatively assess their conservation status. Additionally, historical precipitation data from the National Water and Basic Sanitation Agency (ANA) were used, and linear models were fitted to evaluate the influence of precipitation on NDWI classes. The results revealed a significant increase in surface areas classified as dry and a reduction in flooded and moist areas throughout the time series. The observed variations showed no significant relationship with annual precipitation, indicating that human pressures exert a greater influence on water availability in these vereda ecosystems. The Rapid Ecological Assessment identified varying levels of degradation across the evaluated areas, primarily linked to urban expansion, agricultural and livestock activities, damming, roads, the presence of invasive alien species, and changes in vegetation cover. It is concluded that the vereda (palm swamp) in the Ribeirão das Araras sub-basin has undergone significant changes in water content over the past 40 years, suggesting that the intensification of human activities may have contributed to reduced water availability in this environment. This highlights the need to strengthen monitoring efforts, ecological restoration, and public policies aimed at conserving Cerrado wetlands. Furthermore, integrating remote sensing with Rapid Ecological Assessment proved to be an efficient, low-cost approach with potential for environmental monitoring, capable of informing conservation and management strategies for the veredas of the Ribeirão das Araras sub-basin.