Species Diversity And Distribution Of Rotifers In Winter In Pearl River Basin,China

To understand species diversity,community composition and spatial distribution of rotifers,we took samples from December 2015 to January 2016 in Yunnan,Guizhou,Guangxi and Guangdong province.In total,167 samples were collected.We divided sampling sites into two altitude gradient classes(the second ladder(500 m<altitude<4000 m),the third ladder(<500 m)following Chinese geographic zones,and four habitat types(reservoirs,lakes,ponds and temporary water bodies).The results were summarized as follows:1.25 genus and 135 rotifer species were identified in Pearl River Basin samples.Keratella,Brachionus,Trichocerca,Polyarthra,Lecane and Euchlanis showed higher frequency in all of samples,more than 58%.2.On average,17 species for a single sample were identified in the second ladder class,and 15 species in the third ladder.Keratella cochlearis and K.tecta were the dominant species in the second ladder and K.tecta and Brachionus calyciflorus in the third ladder.3.For dissimilarity between rotifer communities indicated with Bray-Curtis distance,it was higher in the third ladder than in the second ladder.Both longitude and altitude were main factors affecting the rotifer species richness in the second ladder.In contrast,dissolved oxygen(DO)and p H were the main factors for rotifer species richness in the third ladder.4.From the habitats,Rotifer communities in reservoirs and lakes were dominated by K.cochlearis and by K.tecta,by K.tecta and B.calyciflorus in ponds and by K.cochlearis an K.tecta in temporary water bodies.Dissimilarity between rotifer communities in habitats showed a ranking pattern: temporary water bodies>ponds>lakes>reservoirs.