Can a Top Predator Persist After One of the World's Largest Mining Dam Failures? Occupancy Dynamics of the Neotropical Otter in Brazil's Paraopeba River

ABSTRACT Human activities are known to directly impact vertebrate populations worldwide. Among these disturbances, mining dam collapses pose serious threats to freshwater ecosystems, yet their ecological effects have only started to be understood, not only for semi‐aquatic mammals but for biodiversity and ecosystem functioning overall. We assessed post‐disturbance occupancy dynamics of the neotropical otter ( Lontra longicaudis ) in the Paraopeba river, Brazil. Over five monitoring seasons (2021–2025), we surveyed five river stretches upstream and downstream of the Ferro‐Carvão confluence and fitted multi‐season occupancy models. We estimated initial occupancy, colonization, extinction, and detection probabilities as functions of distance to the confluence, time since the collapse, water flow velocity, turbidity, and the proportion of natural riparian cover. Our study reveals that otters maintained a continuous distribution and high occupancy probabilities across the monitored river, including stretches affected by tailings. Occupancy dynamics were primarily associated with distance from the confluence, while other environmental variables showed no effects, consistent with a degree of species' tolerance to moderate habitat alterations. Otter occupancy was consistently lowest within the hydroelectric reservoir stretch, suggesting distinct constraints in impounded environments. Our findings demonstrate the post‐disturbance persistence and tolerance of L. longicaudis to moderate habitat alteration following a large‐scale environmental disaster and provide important guidance for conservation and management of freshwater systems affected by mining and other anthropogenic disturbances.