Identifying Human Disturbance Gradient in a Neotropical Coastal Plain River Affected by Multiple Stressors

Código

XXVI-SBRH0198

Autores

Renata Ruaro, Leonesa da Silva Belanha, Andre Andrian Padial, Júlio César Rodrigues de Azevedo, Otacilio Lopes de Souza da Paz

Tema

J - Qualidade da Água em Sistemas Ambientais

Resumo

Aquatic and coastal ecosystems are increasingly impacted by anthropogenic activities, particularly through the loss of riparian vegetation, pollution, urban expansion, and the spread of invasive species. This study aimed to evaluate environmental conditions and detect a gradient of human disturbance in the Guaraguaçu River, located on the southern Brazilian coastal plain and influenced by multiple stressors. To accomplish this, we conducted quarterly assessments throughout 2024 at 22 sites distributed along the Guaraguaçu River's main channel and its two tributaries, the Pery and Pombas Rivers, analyzing water and sediment quality and the dominance of invasive macrophytes. Principal Coordinates Analysis (PCoA) was used to summarize the data, and axis scores were employed to characterize the environmental gradient. The analysis revealed a distinct gradient in environmental conditions, primarily shaped by human-induced pressures across the watershed. Among the stressors evaluated, water pollution was identified as the main contributor to environmental degradation within the Guaraguaçu River Basin. Parameters such as conductivity, salinity, ammonia, and orthophosphate were the most influential in shaping this gradient. The highest concentrations of these variables occurred in the Pery River and in downstream sections following its confluence with the Guaraguaçu River, highlighting the deterioration of environmental quality in this tributary and its influence on the lower Guaraguaçu River.