Distinct difference of littoral rotifer community structure in two mangrove wetlands of Qi'ao Island, Pearl River estuary, China

Abstract

Background: Less study was focused on the ecological community oflittoral rotifers than on pelagic area worldwide. Moreover, rotiferswere overlooked mostly due to the improper sampling methods and lack ofexperienced taxonomists for ecological researches, and the diversity androle of estuarine rotifers in ecological systems were underestimatedseverely.Results: A long-term investigation of the littoral rotifer in a shallowmangrove swamp (MS) and a tidal creek (TC) of Qi'ao Island, the PearlRiver estuary of southern China, revealed significant differences of thecommunity structure at different sites and in different seasons.Ninety-four monogonont rotifers were detected in total. The averageabundance of rotifer at MS (97.0 individuals/L) was lower than that atTC (140.8 individuals/L), but all average diversity indexes at MS werehigher than those at TC. The main species at MS were Colurella sp.1,Encentrum marinum, Colurella adriatica, Synchaeta cf. kitina, Synchaetasp., and Cephalodella cf. innersi, whereas they were Synchaeta cf.kitina and Brachionus angularis at TC. The rotifer community wascorrelated with the salinity and total nitrogen group most at MS, whiletemperature contributed most at TC.Conclusions: This study revealed higher diversity and abundance oflittoral rotifers at the two close mangrove wetlands of Qi'ao Islandcompared to other studies. Different kinds of biotopes at the two sitesdisplayed significant difference of the community structure, which wasmainly due to the abundance of different main species present at the twosites. The peculiar environment of MS created an unusual rotifercommunity which had more marine species with higher abundance mostly inwinter.