The Research On The Relationship Between The Waterbird Communities And Habitat Factors On Nanhui Biantan After Reclamation

Reclamation has played an extremely important role in promoting regional economic development, but it is also triggering a series of ecological problems. Coastal mudflats provide a natural environment for many biological populations, but biological species and biodiversity gradually reduces with the reclamation project on going. Water birds are a special class of groups, their migratory wetland-dependent results in their sensitivity to habitat quality and its structural changes. The interferences affect the bird habitats and disrupt the original relationship of birds and habitat, and ultimately the ecosystem health and stability of the wetlands will be destroyed.Nanhui Biantan is on the way of shorebirds migrating along the East Asian-Australasian Flyway that stretches from central Siberia and western Alaska south through eastern Asia to Australia and New Zealand. It is one of the largest coastal mudflats which is constantly silting up, it is also one of the key areas for reclamation in Shanghai for a long time. Reclamation activities continue with the dynamic growth of the coastal wetlands. In the past20years, Nanhui Biantan has experienced two large-area enclosure projects. Such an excessive reclamation directly reduce the area of coastal mudflats and makes biodiversity reduce and bring bad effects on wetland ecology and makes the water birds living space shrink at last. When the economic development and the ecological protection are in conflict, we need to find a balance between them. The way is to ensure the economic development and at the same time to make sure the ecological protection issues can be resolved. Coastal mudflats in Shanghai are in a dynamic growth process, a "dynamic protection" measures for the coastal mudflats is a good way which is worthy of study. Dynamic protection is a way of habitat replacement or making improvement for habitat quality according to the variation of the habitats. The use and protection of coastal mudflats need to give scientific interpretations between the relationship of the habitats selection of the water birds and the law of the coastal mudflats’dynamic growth.The community character of the water birds and their habitants were studied on Nanhui Biantan. The results give us the importance of wetlands for water birds and some measures for improving the environment being reclamated to bring forward some suggestions for wetlands protection, ecosystem restoration, birds’habitats optimization and sustainable managing.The brief of research process as follows:1the artificial wetlands behind the seawall:From November2009to March2010, an avian study was undertaken in the artificial wetlands behind the seawall on Nanhui Biantan, in Shanghai. A total of35bird species of8orders and9families were counted in winter of2009, and the dominant species were water birds; meanwhile, the environmental factors including water level, water area, vegetation coverage, and human disturbance were measured quantitatively. Based on multi-regression analysis and curve estimation between bird community and environmental variables, the results indicated that in winter, the water area and human disturbance correlated with bird species abundance; the water area, vegetation coverage and human disturbance impacted on the bird density; and the water level and water area affected the evenness of birds; water level correlated with water birds species.Above all, the experimental restoration area is the most suitable habitat and at last the paper gives some advices on how to build the artificial wetlands.2the natural costal mudflats before the seawall:Coastal regions are important habitants for migratory shorebirds. The aim of this study is to understand the habitat use by the migratory shorebirds and to develop a conservation strategy for shorebirds. During the spring (from March to May) and autumn (from September to November) of2010, along the coastal region, we selected four typical samples A, B, C and D which had significant differences among their environmental factors (including elevation, total mudflat width, bare mudflat width, human disturbance and vegetation area), then surveyed shorebird individuals in the samples and examined their spatial distribution simultaneously. A total of28species were identified. In spring, the dominant species were Kentish Plover (Charadrius alexandrinus), Whimbrel(Numenius phaeopus) and Lesser Sand Plover (Charadrius mongolus) accounted for more than39.56%of the total number; the rare species were Black-tailed Godwit (Limosa limosa), Common Sandpiper(Actitis hypoleucos),Grey-tailed Tattler(Heteroscelus brevipes) and Sanderling (Calidris alba). In Autumn, the dominant species were Kentish Plover, Dunlin(Calidris alpine) and Common Greenshank (Tringa nebularia) accounted for more than66.98%; the rare species were Red-necked Phalarope (Phalaropus lobatus), Grey Plover(Pluvialis squatarola),Eurasian Curlew (Numenius madagascariensis),Marsh Sandpiper (Tringa stagnatilis) and Grey-tailed Tattler. Significant differences appeared in the characteristics of shorebird communities among the samples of A, B, C and D in spring. The species and individual densities of the shorebirds among the samples were significantly different in autumn by the way of one-way ANOVA.The habitat-selection analysis on the environmental-factor impacting on the shorebird communities was made in the four samples with Canonical Correspondence Analysis.The study results indicated that total mudflat width, vegetation area and human disturbance were the important factors affecting the use of the natural mudflat by shorebirds and the intertidal mudflat of Nanhui coast was a foraging habitat for migratory shorebirds.