30年来武昌湖湿地退化过程与原因

Degradation of Wuchang Lake wetland and its causes during 1980-2010

湖泊湿地是敏感脆弱的生态系统,极易受气候变化和人类活动的影响。通过对长江中下游沿岸武昌湖湿地1980-2010年生态系统变化进行分析,具体包括:(1)选择Landsat MSS影像进行遥感解译,结合GIS技术分析武昌湖集水区的景观变化情况;(2)统计研究区1980年以来的气象水文数据,分析湿地生态系统主要气候因子的变化趋势;(3)结合气候因子和土地利用变化,初步分析武昌湖湿地生态系统变化的自然-人工原因。结果表明,1980年以来,湿地景观发生较大程度的变化:湖域面积减少了近40%,尤其是下湖青草湖水域面积从52.76 km2减少为13.92 km2,萎缩约73.62%。跨湖公路建成以后,集水区内与人类活动关系密切的建设用地面积显著增加。武昌湖湿地温度呈明显的上升趋势,而降雨、蒸散发等气候变量变化趋势均不显著。建设用地、气温与湿地退化的相关性显著,降雨和蒸散发与湿地退化无明显相关性,公路的跨湖修建加速了湿地的退化速度。

The lake-wetland ecological system is sensitive to climate change and human activities. This study investigated the ecological changes of Wuchang Lake wetland （located at the downstream of the Yangtze River） from 1980 to 2010, and the potential causes of wetland degradation. We first overviewed the landscape changes in the study area by analyzing the Landsat MSS/TM imageries; and then examined the dynamics of hydrometeorology during the study period. Based on the analysis of changes of landscape patterns and variations of hydrometeorological variables, the natural and anthropogenic causes of Wuchang Lake wetland ecosystem degradation were discussed and differentiated. Results show that over the past three decades the total area of Wuchang Lake has decreased by 40%. In particular, area of the Qingcao Lake at the downstream of the lake-wetland system has over 73%, from 52.76 km2 to 13.92 km2. The area of construction land, which manifests the human activity in the watershed, had increased significantly since the building of the Anjiu Road across the lake. The average annual temperature in the study area showed a significant increasing trend, while the annual rainfall and evapotranspiration were relatively stable with little variations. We concluded that the degradation of the Wuchang Lake wetland was accelerated mainly by constructions in the area and the increased temperature, while the annual rainfall and evapotranspiration had little influence.