Baseline-Based Assessment on Fragmentation of Coastal Wetland Landscape in Yalujiang Estuary

With the aid of the 3S technology,a baseline landscape of the Yalujiang Estuary was established as reference for analysis and assessment of landscape fragmentation of the coastal wetland therein in 1989 and 2005,using indicators,such as natural landscape index,patch density,largest patch index,patch shape index and contagion index.Results show that the baseline landscape is a useful reference for assessment of landscape fragmentation.The wetland landscape of the Yalujiang Estuary tended to break into patches with natural index declining to 89.373% in 1989 and to 86.691% in 2005.Among the different types of wetlands,reed swamps,mudflats and tidal furrows shrank significantly in acreage with natural index falling down to 69.94%,71.49% and 78.42%,respectively in 2005.The index of patch density of wetlands of all the types increased,with that of reed swamps ranked first,being 18.507,and that of mudflats second,being 6.879 in 2005.Mudflats tended to become more complex in shape of patches while the other types displayed a reverse trend.The contagion index remained high for all the types of wetlands in all the periods,suggesting that the various types of wetlands are distributed in cluster in the Yalujiang Estuary.