Influence of Hydrological Heterogeneity on Rotifer Community Structure in Three Different Water Bodies in Shantou Area, Guangdong (China).

Rotifers, small but essential invertebrates in aquatic ecosystems, are sensitive to environmental changes and are proposed to be indicators of trophic state. However, the effects of hydrological heterogeneity on the rotifer community and the ability of rotifer indices to reflect trophic state across different water bodies are still unclear. Here, we investigated rotifer community structure in different seasons in the three types of water bodies: Han river downstream (HD), Reservoir (RE) and Tidal creek (TC) in Shantou City, Guangdong, China. Our findings revealed that rotifer community structure differes significantly among the three water bodies, resulting from a dominance of Keratella cochlearis, Anuraeopsis fissa and Polyarthra vulgaris, who largely accounted for the differences in water bodies. Chlorophyll-a and transparency were the main environmental drivers in RE rotifer communities, while total nitrogen, total phosphorus and salinity were the main factors in HD and TC communities. Rotifer abundance and the rotifer trophic state index decreased in the order: RE > HD > TC. However, both the Sladecek's B/T quotient and the Keratella- index decreased in the order: HD > RE > TC, which was in accordance with the Carlson's trophic index. We conclude that it is efficient to use rotifer composition in water quality assessments when comparing different water bodies. Alpha diversity of rotifers was the highest in HD, which is consistent with the intermediate disturbance hypothesis. Hydrological heterogeneity is the micro-factor that regulates rotifer community structures in the Shantou area.