eDNA reveals urban habitat-specific sorting of a mixed regional fish fauna into distinct biodiversity and life-history assemblages

Urbanization is altering freshwater ecosystems across the globe, with well-documented impacts linked to land-use changes, water flow alterations, and habitat degradation. However, the organization of biodiversity among adjacent urban water bodies, which vary in hydrologic connectivity, disturbance transmission, residence time, management history, and species movement opportunities, remains uncertain.

This complexity makes it difficult to interpret fish communities within cities, as fish presence might reflect contemporary habitat filtering or historical factors like native persistence, basin-to-basin transfer, stocking, and nonindigenous introductions.

Utilizing environmental DNA (eDNA) detections, historical records, phylogenetic insights, and species trait data, researchers delve into the fish communities of the Charlotte metropolitan region. The findings reveal a diverse array of fish species that also exhibit a distinct pattern of structured biodiversity profiles across various taxonomic, phylogenetic, functional, and life-history dimensions.

Notably, enclosed habitats are dominated by larger-bodied species with high fertility and rapid reproductive cycles, whereas free-flowing habitats host different species.

The study's species-level occurrence models fail to support a straightforward correlation between specific traits and habitat types. Instead, the research highlights that urban aquatic environments can effectively categorize historically mixed regional species pools into distinct life-history profiles within individual assemblages. At the same time, these habitats retain traces of evolutionary and historical biogeographic influences.