洞庭湖区湿地景观变化分析

Changes in wetland landscape in Dongting Lake area

洞庭湖湿地是我国最重要湿地系统之一,具有多方面功能和价值,主要由河流、湖泊、水田、沼泽、滩地、库塘等几种类型组成。本文利用1980年、1990年、2000年3个时段的Landsat MSS和TM影像及GIS技术对洞庭湖区湿地景观变化进行研究。结果表明,洞庭湖区湿地总面积呈减少趋势,人工湿地面积有所增加,自然湿地面积减少,其中湖泊面积减少最多。这是人类和自然共同作用的结果,其中人类对湿地的改造是导致变化的主要原因,但洞庭湖的泥沙淤积是湖泊面积减少的根本原因。湿地景观的改变导致该区生态环境质量下降,生态功能退化。

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.