Study On The Typical Vegetation Restoration Models Of Urban Lake Wetlands In Wuhan Based On Plant Community Analysis

In recent decades, urban wetlands in our country are facing the regional ecological environment being destroyed, the natural landscape vanishing, the biodiversity reducing, the ecosystem function getting lost, same like those kinds of ecological disasters along with rapid industrial and agricultural development, population increase and urbanization process acceleration. Therefore, recovery and reconstruction of wetland ecosystems, thus creating favorable wetland ecological environment and maintaining the ecological functions of wetland is important and necessary. As one of the three basic elements of wetland ecological system, wetland vegetation restoration would play a vital role in the wetland protection and ecological restoration. On the basis of higher plants investigatation of 25 urban lake wetlands of Wuhan city, the type and structure of Yandonghu lake wetland higher plant communities were studied using TWINSPAN and DCA. Combining with literature comprehensive achievement, the reference target of Wuhan lake wetland vegetation restoration was presented. Through analyzing plant degradation status, the 25 lake wetlands were classifiedThen the causes of various types of degradation and the relationship between distribution of dominant species and disturbance were studied. The wetland species's application value was evaluated. One lake was selected from each class of severe degradation lakes, and the status of plant communities were analyzed as the basis. Then the corresponding restoration models were put forward, which would provide reference to vegetation restoration of this region and adjacent area. The main conclusions are as follows:(1)The plant community types, composition and their structure in Yandonghu Lake which had get moderate disturbance, Liangzihu Lake (1998-2002a) and East Lake (1992-1993 a) wetland had been revealed as the typical of Wuhan's, which would provide reference for the vegetation restoration.(2) Mainly displayed in the form of species abundance reduction on varying degree and the dominant species changement, the degeneration phenomenon of Wuhan urban lake wetlands is quite common. According to the vegetation degeneration degree and reasons, the urban lake wetlands which were subject to intensive disturbance were divided into 6 kinds, including intensive human activities'disturbance type, human activities & aquaculture interference type, wetland invading & sewage disposal interference type, intensive aquaculture interference type, sewage disposal & human activities disturbance type, wetland habitat aridity & sewage disposal interference type. (3)Land use around lakes, Function of lakes, Shoreline features, range of water level fluctuation and water quality had some relationship with the distribution of wetland dominnat species. In addition, the original habitat of wetland plants in Wuhan urban lake tended to become increasingly fragmented and small patches of wetlands could not link with each other, so species reproduction and diffusion process were been cut off or blocked. These kinds of artificial effects on the distribution of wetland plants are also great. The analysis of dominant species' distribution pattern would provide criterion for species selection and structure configuration during the process of plant restoration model construction.(4)The application value such as water cleaning, ornamenting, water and soil conservation, production and economic value and the ecology ecad of 282 native plant species of Wuhan was assessed. Several exotic species, such as Alternanthera philoxeroides, Plantago virginica, Geranium carolinianum, Erigeron annuus and Daucus carota etc. were distributed widely, and dominant in the communities. It demonstrated the environment of lake wetlands had changed and native vegetation had been destructed. Certainly, there were also many exotic species which had been locally naturalizerd or widely cultivated did not hazard the original vegetation and environment, so they could be appropriately applied depending on their good traits.(5)6 lakes were selected according to the reason of vegetation degeneration and plan function of them, as the sites constructing restoration models which were based on the existing community types and composition, plant species characteristics and relationship. The productive and economic model, the landscaping model, the ecological protection model and the comprehensive efficiency plant community model were constructed. These models could be applied under the condition of plant community degetation and functional requirements of the lake wetland vegetation restoration.