The Diversity Of Community And The Ecology Of Macrobenthos In Laizhou Bay

Based on the surveys of macrobenthos in Laizhou Bay, May(spring), August(summer) and October(Autumn) of the year 2014, the community structure and diversity of macro benthos in this area was analyzed by an index of relative importance IRI, the ecological diversity indices including Margalefˊ species richness index(D), Shannon-Winner diversity index(Hˊ), and Pielouˊs evenness index(Jˊ), multivariate analysis MDS and CLUSTER from SOFTWARE 6, the BOPA index, the functional group, the correlation analysis between the macro benthos and environmental factors. In the investigated area, 37o12ˊ~37o40ˊN、119°05′~120°00′E, 20 samples were set up. The results showed that 177 species were identified from the samples, while Mollusca and Annelida were the most important phyla in our study and the number of species in Summer and Autumu are more than Spring. Biomass and density of macrobenthos are of larger variations in time and space scales, with ANOVA showing that the difference of the former differ significantly while the latter not significant. Dominants species, which were defined as index of relative importance(IRI), value more than 1000, were belong toAlvenius ojianus and Musculus senhousia in Spring, while Alvenius ojianus in Summer and Autumn. The diversity index of Shannon-Winner diversity index(Hˊ), Pielouˊs evenness index(Jˊ) and Margalefˊrichness index(D) varied from 2.043~4.014,0.455~0.942, 1.557~4.700. Cluster and n Mds annlysis showed that commusity of macro benthos in the Laizhou Bay was in unstable state, with the difference varied from three seasons. BOPA index showed that the environment in the Laizhou Bay was destructed poorly. The functional group of macro benthos showed that group C and D were dominant, with the percentage of the species number in different functional groups to the total species ranked in the order of C>D>Pl>O>Ph. There were four trophic levels in the macrobenthic community and their food source, and the macrobenthic functional groups belonged to the Ⅱ, Ⅲ and Ⅳ trophic levels. A complicated food web was composed between all the trophic levels. Pearson relation between diversity index and environment factors showed that: in different seasons, different diversity indices differ from each water quality parameters, having no regularity at all; sediment factor analysis had no correlation, while having great correlation with fine sand.