Studies On The Community Structure And Biodiversity Of Macrozoobenthos In Poyang Lake National Nature Reserve And Nearly Rivers

Macrozoobenthos are one of the most important components of freshwater biotic community. They play an important role in the freshwater ecosystem. The Poyang lake National Reserve is an essential habitat of rare migratory birds. The macrozoobenthos are one of the food resources of birds. Understand the current status of macrozoobenthos community; it is necessary for us to protect rare migratory birds. We carried out an investigation of macrozoobenthos community in2011(the flood water seasons and drought water seasons), and analyzed the macrozoobenthos community structure, species composition, density, bio mass, dominant species and their temporal and spatial variation. The main results are as follows:1. A total of79species belongs to16genera of macrozoobenthos were found in Poyang lake reserve and nearly rivers, of which24species,19genera and7families of Annelida (30.4%of the total number of species),30species,17genera and9families of Mollusca (30.8%of the total number of species), and25species,21genera and11families of Arthropoda (54.3%of the total number of species).69species were found in Poyang lake reserve (87.3%of the total number of species),15species in Xiu river and43in Gan river.2. Density and biomass varied in different seasons and sampling sites obviously. Mean density of macrozoobenthos was182.82±161.83ind./m2; mean biomass was71.13±55.12g/m2in the Poyang lake reserve and nearly rivers. Mean density of macrozoobenthos was198.86±121.36ind./m2, mean biomass was71.81±42.32g/m2in the Poyang lake reserve. Mean density of macrozoobenthos was42.50±22.43ind./m2, mean biomass was75.53±126.40g/m2in rivers.3. Shannon-Wiener diversity index, Pielou uniformity index and Margalef richness index were used to analyse the diversity of the macrozoobenthos. Shannon-Wiener index was the highest in Dahuchi (3.66), and the lowest in river VI(1.20); while Pielou index was the highest in river IV (0.93) and the lowest in river VI (0.36); and Margalef index was the highest in Xiang Lake (5.01) and lowest in Sha Lake and VI (1.29). 4. The dominant species were Bellamya purificata (Heude), Bithynia fuchsiana (Moellendorff), Parafossarulus sinensis (Neumayr) in Poyang lake reserve and The Dominancy is0.148,0.100,0.130,0.027; The dominant species was Corbicula fluminea in rivers and the dominancy is0.091.5. In flood water seasons, the relationships between32species of macrozoobenthos and8environment variables in Poyang lake reserve were revealed by Redundancy analysis (RDA). The results demonstrated that Conductivity, Secchidepth, PH, Water temperature were function as an important environmental factors in regulating the distributions of macrozoobenthos. And the results of RDA grath showed that different kinds of macrozoobenthos have different distribution structure characteristics depend on the4major water environmental factors.