The Study On Dynamic Change Of Wetland Landscape In Poyang Lake Based On Rs And Gis Technology

Wetlands, which are named"kidney of the earth", have gained much attention recently because of its unique and important value to ecological system, and the study of wetlands has become the international popular research fields. Remote sensing (RS) and geographic information system(GIS) as the earth observation of important high-tech means, provide a new method for wetland research and technical support. Only use remote sensing method can accurately mastering the distribution and dynamic change of the waters and the grass, mudflats wetland in Poyang Lake , which is the China's biggest lake with high quality environment.The target of this research based on the status quo and transformation of wetlands in Poyang lake . The research takes landscape ecology as theoretical instruction and method, and satellite remote image as the source data, with RS and GIS technology; we determined the boundaries of natural wetland in Poyang Lake. After that, We classified the 20 ETM images which represent monthly and different water level of natural wetland in Poyang Lake, and obtained four types of wetlands : water, mudflats, grass island and the beach.. This paper analysis the landscape pattern through a series of landscape index, study how will the wetland change when the water level regular changes happen . The results show :(1)The area of natural wetlands in Poyang Lake is 3635.52 km2.(2)Water, as the dominated landscape of Poyang lake, its area increase as the water level power-up, and its change extent is bigger , which the maximum covers an area of 2000 km2 bigger than minimal area. The area of grass ,mudflats and beach has the negative correlation with the water level: the average patch area of grass is larger than others in dry season;mudflats has the biggest patch number (PD) that indicate mudflats'Broken-rization degree is high; the beach with the smallest area in the Poyang Lake are more concentrated.(3)In winter, with low water lever ,wetland landscape in Poyang lake has the high index of diversity and evenness ,that stands its has high degree of fragmentation. In summer, the flood period , the water level is higher, landscape is simple, diversity and evenness index is lower.