Data from: How do substrate composition and environmental variables influence the richness and abundance of molluscs in an urban river within a semi-arid region?

This study investigates the influence of substrate composition and environmental variables on the richness and abundance of freshwater molluscs in the urban stretch of the Guaribas River, located in the semi-arid region of Piauí, Brazil. Bimonthly collections were conducted between October 2021 and August 2022 across five sampling points, where molluscs were gathered from sediment and macrophyte substrates. Environmental parameters, including pH, water temperature, and water column depth, were also recorded. A total of 2479 individuals were identified, predominantly gastropods, with higher species richness and abundance observed in macrophyte substrates compared to sediment. Statistical analysis revealed a positive correlation between mollusc abundance and macrophyte presence and a significant interaction between pH and temperature on mollusc distribution. The results highlight the crucial role of macrophytes in enhancing habitat complexity and supporting mollusc diversity while demonstrating the negative impact of sediment pollutants in urban river systems. These findings provide insights into the ecological dynamics of molluscs in semi-arid environments, contributing to conservation and management strategies in these regions.