The Study Of Macrobenthos Community Structure And Biodiversity In Huanghe River Estuary Wetland

The field surveys of macrobenthos and vegetation were carried out in Huanghe River estuary wetland in May and September of 2006. The main research works include the species and compositions of the macrobenthos, the community structure and biodiversity, together with the relationship between the macrobenthos and the plant spicies. The paper has adopted the ABC curve to analyze the effects of the human disturbance.The main results show as follows:(1) In Huanghe Estuary Wetland, there are 33 families and 38 genus and total 41 species of macrobenthos found in the research. There are 23 species of arthropods, 9 species of annelida , 8 species of mollusca and 1species of larva respectively. The ecological characters of macrobenthos are eurythermal, euryhaline and hypoxia-tolerant environment. The fauna is consisted by marine organisms, brackish water species and species near river.The vertical distribution of species and individual amount of macrobenthos decreases with the increasing of soil depth, and shows distinctly accumulation in the top soil.In different seasons, annelid species is richest in May and arthropods species is richest in September. The species abundance decreases as the habitat tends to moderate gradually in May, ie. aquatic plant community> hygrophyte and mesophytes community >xerophyte community. In September, hygrophyte and mesophytes community> aquatic plant community > xerophyte community.(2) There are close relationships between the plant communities and macrobenthos communities in soil, which is the more similarity of the former ones, the more that of the latter ones. The dominant species of aquatic plant community is marine annelida, dominant species in hygrophyte and mesophytes community is specific species in estuary, and in xerophyte community is the terrestrial arthropoda.Through the analysis of cluster and MDS ordination, intertidal zone upside and middle part of mud beach (1 and 2) belong to aquatic plant community, The dominant species of aquatic plant community is marine annelida, dominant species in hygrophyte and mesophytes community is specific species in estuary, and in xerophyte community is the terrestrial arthropoda.(3) The macrobenthos species in Huanghe River estuary is few and the diversity is low. The macrobenthos community abundance diversity, dominance and enenness indexes keep accordance in May and September except special case.The abundance index numerical value range from 0.6266~2.7704, diversity of that is between 1.2325~8.2325. The sequence is aquatic plant community > xerophyte community > hygrophyte and mesophytes community. The vertex in September is cotton field and the nadir is grass land community in September.The trend of evenness is aquatic plant community > xerophyte community > hygrophyte and mesophytes community. There is little difference between the two months and the numerical value range from 0.3563 to 1.0000. The abundance index is between 0.1644 and 0.2058, the sequence is xerophyte community > hygrophyte and mesophytes community > aquatic plant community. The species, distribution and quantity of macrobenthos can reflect the moisture status of wetland.(4) The plant community diversity have close relationship with the diversity of macrobenthos community. In May, most of the relationship present negative, the species number, abundance and evenness indexes of plant community have extremely obvious negative relationship with species number of macrobenthos, the relative coffecients is 0.776,0.896,0.776 (α≤0.01). The species number presents obvious negative relationship with the species number, abundance and diversity index of macrobenthos, relative coffecients is: 0.896,0.609(α≤0.05). In September, a positive relationship was observerd, the individual number and the species number show extremely positive relationship, relationship coffecient is 0.803(α≤0.01), the macrobenthos individual number have obvious positive relationship with the individual number and diversity index, relative coffecients are: 0.787, 0.686(α≤0.05).(5) The type of vegetation, human disturbance and salinization of soil influence the macrobenthos community structure greatly.ABC curves show high diversity indexes of communities under moderate and none disturbance by nature and human-being. Whilst under heavy disturbance, the diversity indexes decrease in accordant with that of macrobenthos community.The salination and PH value have obvious relationship with the species number, abundance and diversity of macrobenthos in May; on the contrary, there is no close relationship between them in September.