Evolution And Characteristics Of Wetland In

The lagoon wetland located in the transitional zone between the land and the sea,presenting one of the most abundant biodiversity, high productivity and most valuable ecosystems. Lagoon wetland is a region where the natural factors and the human factors co-function, the landscape structure changed dramatically. Due to land reclamation and aquaculture, the area of wetlands is shrinking constantly, the landscape fragmentation is getting more obvious. By the influence of inputs of agricultural and industrial wastewater, TN and TP content far exceeded in the lagoon,eutrophication degree is higher, the number of red tide increases, which bring serious damage to the wetland ecological system.Wanpingkou lagoon wetland located in the east of new urban area of Rizhao,with the rapid development, lagoon wetland ecological environment has been undergoing significant changes. Therefore, this paper takes Wanpingkou lagoon wetland in Rizhao as the study area. Supported by the RS and GIS techniques,extracting and classifying the wetland information to the four remote sensing images of 1990,1997,2003 and 2014, study the landscape pattern evolution of the Wanpingkou lagoon wetland from 1990 to 2014 through the landscape pattern index.By monitoring the water quality of lagoon wetland from 5 to 10 month in the 2014,using the correlation evaluation method to evaluate the present condition. According to the existing problems that the landscape pattern status and water environment status of the Wanpingkou lagoon wetland, finally, proposing the corresponding countermeasures and suggestions, providing scientific reference for the protection of wetland resources and regional sustainable development. The main conclusions are as follows:1.From 1990-2003, the area of shallow lagoon, green land and construction land is increasing, the area of bare land is decreasing, while for the construction of the Olympic water park, the culture pond and arable land all converted to other land use types in the after 2003. Overall, the indices of wetlands landscape pattern reflect that the landscape diversity show a decreasing trend, while the landscape evenness index,concentration and connectivity all increase. From the results of analysis to the landscape pattern, the construction of the Olympic Water Park optimized the landscape pattern of Wanpingkou lagoon wetland in a certain extent, the area of water and plants area expanded, the landscape fragmentation indices generally decreased,but the human disturbance such as urban construction and tourism development is gradually increased.2.According to the sea water quality standard, the 15 water quality monitoring points of Wanpingkou lagoon wetland in the 5-10 month, the pH value of part of seawater attained the quality standards for Grade I,Ⅱsea water. From May to October,DO content, Chl-a concentration and TP concentration the quality standards for GradeⅡsea wate in addition to June, TN concentration exceeded the standard limit value attained the highest in July. In space, the content of DO in the tenth monitoring points and the concentration of Chl-a in the tenth, eleven monitoring points exceeded the standard limit value, the rest of the monitoring points attained the quality standards for Grade Ⅱsea water.3.Single-factor index method shows that wether in the time scale or spatial scale,TN and TP are the main pollution factors. Nemero index method showed that the water quality of Wanpingkou lagoon wetland is still in a state of light pollution.The comprehensive nutrition state index showed that the water quality is in the degree of middle nutrition.