1960-2005年民勤典型绿洲-荒漠过渡带景观格局与动态

利用ERDAS、GIS等技术，系统分析了1960—2005年间民勤典型绿洲 荒漠过渡带的景观格局与动态.结果表明：林地和耕地是影响过渡带景观变化的主导因素；研究期间，绿洲向外围扩张了2～3 km，且过渡带向荒漠位移，过渡带宽度由1960年的4 km增至1987年的约9 km，之后又迅速变窄；1978—1987年间，研究区景观变化强度达到历史最高水平，1998年后，景观格局相对稳定；整个过渡带景观破碎程度较大的时期出现在景观类型转化最快的1978—19
87年，景观较破碎的区域出现在距绿洲边界2 km处和造林区.1960—2005年间，研究区乔木林趋于消失；灌木林在1987年前大面积增加，之后急剧减少；耕地开垦强度在1960—1998年间持续增加，1998年之后有所降低，但研究期间的弃耕率则呈直线增加趋势.

Landscape pattern and its dynamics in typical oasis-desert transitional zone of Minqin Region in 1960-2005

By using ERDAS and GIS techniques, a systematic analysis was made on the landscape pattern and its dynamics in typical oasis-desert transitional zone of Minqin Region in 1960-2005. Forest land and cultivated land were the dominant factors leading to the landscape change. During the research
period, oasis expanded toward the periphery by 2-3 km, and the transitional zone moved toward desert, with its width increased from 4 km in 19
60 to about 9 km in 1987 and decreased rapidly then. In 1978-1987, the landscape change reached the historically highest level; but after 1998
, the landscape pattern became relatively stable. In the whole transitional zone, the period with higher fragmented index occurred in 1978-1987, during which, the quickest variation among patch types was observed. The fragmentized regions were located in the area 2 km from oasis and in the forestation area. In 1960-1987, arbor forest tended to vanish. Shrubbery area increased widely before 1987, and decreased sharply since then. The intensity of land reclamation kept increasing in 1960-1998 but decreased after 1998, while the abandon rate had a trend of linear increase during the research period.