Community responses of freshwater rotifers to concrete substrates and water quality in tropical urban wetlands

Abstract Urban wetlands are especially vulnerable to environmental changes, as impervious surfaces disrupt hydrological cycles and reduce biodiversity, with cascading impacts on zooplankton communities. This study examines how rotifer biodiversity responds to wetland imperviousness in tropical urban wetlands by comparing rotifer assemblages between concrete-substrate and semi-natural wetlands and the roles of water quality in shaping rotifer communities within a university campus in a growing urban area of Nakhon Pathom (Thailand). Concrete-substrate and semi-natural wetlands exhibited slight but significant differences in rotifer density and species richness, but showed no significant difference in the Shannon–Wiener’s diversity index and Pielou's evenness index. Community composition was different between wetland types, despite a substantial overlap in species components. Our findings reveal that concrete-substrate wetlands support higher rotifer abundance but favour eutrophic-tolerant species, indicating ecological imbalance rather than true biodiversity. Moreover, concrete-featured wetlands also modified the relationships between rotifer diversity and water properties, suggesting that rotifer–environment interactions vary between concrete-substrate and semi-natural systems. Whilst rotifers show potential as bioindicators, our findings challenge the use of rotifer diversity alone as an indicator of wetland health. Future urban wetland design and management should prioritise habitat heterogeneity in artificial wetlands whilst restoring existing natural landscapes in urban areas.