| Zoobenthos play an important part in wetland ecosystem and its community structure can reflect the conditions of bottom sediment, water quality, water temperature and some other biological factors. The research on the concept of zoobenthos and the function of zoobenthos in natural wetlands ecosystem were overviewed in this paper. Features of zoobenthos community ecology research, methods and some results (such as the difference disturbance of zoobenthos, the relationship with environmental factors and bio-indicators of water health) were summarized. Authors made several suggestions on the principal aspects of further strengthening and promoting ecological researches on the Zoobenthos in China.With development of human activity such as reclamation and the process of biological invasion, habitat disturbance has strong effect on the macrobenthic community. In order to research the impact and effect of habitat disturbance on macrobenthic community, we studied at Lingkun Island, Wenzhou City, Zhejiang Province during Nov. 2005 to Nov. 2006. Based on the data collected, the macrobenthic community and niche analysis of creek at autumn in diked tidal flat, biodiversity comparison of macrobenthic community in diked tidal flat and natural tidal flat, seasonal variation and functional groups of macrobenthic communities at diked and natural tidal flat and the ecological impact of introduced Spartina alterniflora invasion on macrobenthic communities were analyzed in this paper. The main results were as follows:(1) In Nov. 2005, the macrobenthic community and niche analysis at creeks in three diked tidal flats were studied at Lingkun Island, Wenzhou City, Zhejiang Province. The result showed: Altogether 31 species belonging to 19 families, 7 classes and 6 phyla were collected, most of which were gastropoda, lamellibranchia, crustacea and polychaeta. In the different habitats of the creeks (the grass flat, the bank of creek and the bottom of the creek), the composition and abundance of the macrobenthic were different from one other. There were 16 species in the grass flat, 21 species in the bank of the creek and 13 species at the bottom of creek. The macrobenthic structure and life forms of the creeks were different in these three habitats, and showed that the creeks were changed regularly with the environment factors. In general, the Margalef's species diversity index: BaC > BoC > GF; the Shannon-Wiener's index: BaC > Boc > GF; the Pielou's index: BoC > BaC > GF; the Simpson's index: GF > BaC > BoC. The analysis of the niche breadth and niche overlap showed that these two were closed related to the distribution and density of the species, which revealed that the niche breadth and the niche overlaps reflect the species distribution, the abundance and the species ability of utilizing the environmental resource. Combined with the data of the four times extraction of the density of macrobenthic species, using the Hierarchical Cluster of between-groups linkage method and the Non-matric Multidimentional Scaling method, these species could classify into some groups.(2) We addressed the influence of reclamation on community structure by comparing macrobenthic communities in a natural tidal flat and creek of a tidal flat diked in 1997. Sampling was conducted during Feb. to Nov. 2006 near Lingkun Island, Wenzhou Bay. Eight sampling plots (4 each in natural and diked systems) represented different macrobenthic habitats, including two invaded by Spartina alterniflora. In the investigation, a total of 36 species were found, belonging to 22 families, 8 classes, and 7 phyla, most of them being arthropods, mollusks and annelidas. Results indicate that after diking, species richness decreased and the composition of species also had changed. There were 32 species in the natural tidal flat, but only 27 macrobenthic species could be found in the diked tidal flat. The species composition of various macrobenthic communities, life groups and life forms on species of the macrobenthic community in various habitats, the density characters of quantitative sampling exhibited the structure of macrobenthic communities were highly related to the condition of habitats. The niche breadths of the macrobenthos species and biodiversity indices were also analyzed in the paper. Shannon-Weiner index H' was much higher in 2(high tide level and middle tide level) of the 4 habitats within in diked and natural tidal flats. Plots with Spartina alterniflora exhibited lower H' and J than other plots nearby which were unvegetated and similarly influenced by tidewater. Thus, invasion by Spartina alterniflora has already influenced and changed the macrobenthic community in these habitats. The similarity index Jc, paired t-tests, the hierarchical cluster of between-groups linkage method and the Non-metric Multidimentional Scaling (MDS) method reveal that the influence of tidal level on macrobenthos distribution is much stronger in the natural flat than in the diked tidal flat.(3) We addressed the influence of reclamation on seasonal variation of community structure and functional groups by comparing macrobenthic communities in a natural tidal flat and creek of a tidal flat diked in 1997. Sampling was conducted during Feb. to Nov. 2006 near Lingkun Island, Wenzhou Bay. Eight sampling plots (4 each in natural and diked systems) represented different macrobenthic habitats, including two invaded by Spartina alterniflora. In the investigation, a total of 36 species were found, including 24 species found in quantitative sampling, belonging to 22 families, 8 classes, and 7 phyla, most of them being arthropods(13 species), mollusks(12 species) and annelidas(5 species). Based on the data collected, the Two-way ANOVA analyze between season and tide level on the density of macrobenthic communities, the number of species and the biodiversity indices(Margalef S, Pielou J, Simpson D) were analyzed in the paper. Results indicate that the structure of functional groups and communities were highly related to the condition of habitats. The number of species, the density of communities, Margalef S, and Shannon-weiner H'differ significantly among seasons in the diked tidal flat, and this result reveal that the influence of season variation on macrobenthos distribution is much stronger in the diked tidal flat than in the natural flat. Combined with the data of the four times extraction of the density of functional groups, using the Hierarchical Cluster of between-groups linkage method and the Non-matric Multidimentional Scaling method(MDS), these macrobenthic communities could classify into some groups. The communities in the diked tidal flat were different from these in the natural tidal flat which similarly influenced by tidewater.(4) During 2006 to 2007, the authors studied the macrobenthic community at east tidal flat of Lingkun Island, Wenzhou Bay. We addressed the influence of Spartina alterniflora invasion by comparing seasonal variation, biodiversity indices of different macrobenthic communties and using other analysis methods. Five sampling plots(TH, TM, G1, G2, G3) were set in the research places, three of them representative for different invasion level of Spartina alterniflora and the other two used to contrast. We found a total of 29 in the investigation, belonging to 21 families, 8 classes and 7 phyla, most of them being the arthropods and the mollusks. The result of Paired Samples T Test of Margalef's species richness index S and Shannon-weiner's index H showed that the difference had achieved to the distinct level among seasons and various plots. The value of biodiversity indices and the result of Hierarchical Cluster of between groups linkage method and Non-matric Multidimentional Scaling method showed that the structure of G3 communtiy (completely invasion of Spartina alterniflora ) was obviously distinct from other plots and more simple , for the lowest value of S and H, less number of species and density. These results indicate the structure of macrobenthic community has changed by Spartina alterniflora successfully being invaded.
|
PDF Full Text Request