Changes in wetland landscape in Dongting Lake area

Dongting Lake wetland is one of the most important wetland systems in China,consisting of rivers,lakes,paddy fields,bottomlands,swamps,reservoirs and ponds with high levels of complexity and diversity in function and value.Based on GIS technique and Landsat images for three distinct periods,1980,1990 and 2000,the wetland landscape changes in Dongting Lake area were analyzed.Results show that overall decrease in the wetland area,with specific increases in artificial wetlands and decreases in natural wetlands.Lake area decrease is the highest in all natural wetlands,and mutual conversions among the wetland systems exist.The change reveals the outcome of man's interactions with nature,the effect of man on wetlands being the most important factor of change.Degradation of environmental quality and ecological function in Dongting Lake area is attributed to changes in the wetland landscapes.