A study analyzing riverine fish communities across the Palaearctic, Nearctic, and Australasia realms reveals that anthropogenic pressures have driven rapid changes in community composition, with 30% of species composition changing per decade. These changes include a 13% increase in total abundance and a 7% increase in species richness per decade. Spatial variability in these trends is linked to the strength and timing of anthropogenic pressures, primarily mediated by non-native species introductions. Non-native species often compensate for the negative effects of anthropogenic pressures on native species, leading to biotic homogenization. The study highlights the importance of considering both the complexity of community changes and their drivers to achieve global conservation goals. Riverine fish communities show significant temporal and spatial changes, with non-native species playing a key role in community reorganization. Anthropogenic pressures, including land use changes and habitat alterations, have complex interactions with stream position, influencing community dynamics. The study underscores the need to account for these factors in conservation strategies to address freshwater biodiversity loss.A study analyzing riverine fish communities across the Palaearctic, Nearctic, and Australasia realms reveals that anthropogenic pressures have driven rapid changes in community composition, with 30% of species composition changing per decade. These changes include a 13% increase in total abundance and a 7% increase in species richness per decade. Spatial variability in these trends is linked to the strength and timing of anthropogenic pressures, primarily mediated by non-native species introductions. Non-native species often compensate for the negative effects of anthropogenic pressures on native species, leading to biotic homogenization. The study highlights the importance of considering both the complexity of community changes and their drivers to achieve global conservation goals. Riverine fish communities show significant temporal and spatial changes, with non-native species playing a key role in community reorganization. Anthropogenic pressures, including land use changes and habitat alterations, have complex interactions with stream position, influencing community dynamics. The study underscores the need to account for these factors in conservation strategies to address freshwater biodiversity loss.