<p>Non-native fish significantly contribute to biodiversity loss, with severe ecological and economic repercussions, particularly when they occupy apex consumer roles. This study examines the trophic ecology and niche overlap of native and non-native apex consumers within a floodplain subjected to varying degrees of human disturbance, using stable isotope analysis. Our results reveal that native apex consumers generally utilize a broader resource base than non-native species. However, the degree of trophic niche overlap between native and non-native apex consumers varies with the level of human disturbance: in highly disturbed environments, non-native species exhibit expanded trophic niches and reduced overlap with natives, likely reflecting their generalist feeding strategies and adaptation to altered habitats. Despite these differences, native and non-native consumers occupy comparable trophic positions and rely on similar basal energy sources, though some non-native species depend more on resources linked to anthropogenic disturbance, such as grass-derived carbon. These findings suggest that human disturbance modulates the trophic interactions and ecological success of non-native apex fish, highlighting the importance of considering disturbance gradients when assessing their impacts. Overall, the reduced trophic differentiation in less disturbed environments underscores the strong potential for competition and ecological consequences in these systems.</p>