Habitat Structure Shapes Mollusc Assemblages in an Urban Semiarid River: Implications for Conservation and Public Health

ABSTRACT Fine‐scale environmental drivers shape freshwater mollusc assemblages in urban semiarid rivers. We examined how substrate composition and water chemistry influence mollusc richness and abundance along a polluted stretch of a river in the Brazilian semiarid region. Surveys at five sites recorded 2479 individuals. Richness and abundance were modelled using substrate type and other environmental predictors. Substrate type was the strongest predictor, with higher richness and abundance on macrophytes. From a conservation perspective, recognising substrate composition as a key driver supports management actions such as preserving macrophyte mosaics and reducing nutrient inputs to maintain ecological balance in urban freshwater systems.