近15年甘肃民勤湖区景观格局动态变化分析

Dynamic analysis of landscape changes in the lake-area of Minqin,Gansu,in the past 15 years

在遥感与GIS技术支持下,利用景观格局分析软件FRAGSTATS分别计算了民勤湖区1991年、1998年和2005年的景观格局指数,在此基础上对近15年来的景观格局变化进行了分析.结果表明:近15年来民勤湖区景观格局变化显著;整体景观的异质性下降,优势度上升,景观格局朝农用地和未利用土地单优势度的趋势恶性发展;格局变化主要发生在绿洲与荒漠的交错地带;荒漠化进程大于绿洲化速度,生态环境进一步恶化,生态安全水平降低;景观格局变化受水资源影响和人类活动干扰强烈.

Based on GIS and remote sensing, by applying the spatial pattern analysis software FRAGSTATS of the raster version, we calculated a set of landscape indices in the lake-area of Minqin during 1991 to 2005, corresponding to the three scale levels of patch, class and landscape. Studies on the landscape changes indicared that lake-area＇s landscape pattern changed significantly during the research phase, with the dominance index of the entire landscape on the rise and the landscape heterogeneity being reduced. The pattern shows a simple deteriorating tendency of irrigated land and unused （unexploited or unwrought） land. The changes mainly occurred in the transitional area between the desertified area and oasis. Desertification developed faster than the oasis process. At the same time, the lake-area had the tendency of desertification and the ecological security had been reduced. The landscape pattern changes in the lake-area also had close relationship with the changes in the water resource and were strongly influenced by human activities.