中文摘要：

根据1999年、2006年和2013年的Landsat/TM影像数据,利用GIS技术和Fragstats,分别从景观和类型2个水平上对比研究了综合治理前后民勤绿洲的景观格局及其时空格局演变,结果表明：石羊河流域综合治理前（1999—2006年）,绿洲内以牺牲林地、草地为代价的盲目开垦现象与绿洲沙漠化趋势同时并存,民勤绿洲景观的复杂程度和连通性不断提高,而其景观异质性在降低,绿洲呈破碎化发展趋势;综合治理后（2006—2013年）,民勤绿洲景观斑块形状复杂程度在提高,破碎化程度和斑块连通程度均在下降,而其景观异质性在增加。绿洲景观破碎化程度的下降主要是受湖区绿洲景观破碎化程度变化的影响,该时期,退耕后的生态恢复已初见成效,但泉山区土地沙化和湖区土地盐碱化现象依然严峻。景观指数变化在绿洲尺度和各景观分区尺度上表现出明显差异,说明景观指数存在明显的尺度效应。石羊河流域综合治理措施的实施,改变了民勤绿洲土地利用景观时空格局特征,从而对绿洲生态系统的结构和功能产生影响。

英文摘要：

Based on the TM image of the Minqin oasis in 1999,2006 and 2013,the GIS means and the landscape structure analysis program Fragstates were used to calculate and analyze the landscape metrics and the spatiotemporal evolution at type metrics level and landscape metrics level respectively. The results showed that,before implementing the comprehensive management（ 1999- 2006）,the blind reclamation resulted in the cost of woodland and grassland and oasis desertification,thus the shape complexity and connectivity of landscape in the Minqin oasis were continued to improve,however,the landscape heterogeneity was decreased,and the oasis was in a fragmentation trend. After implementing the comprehensive management（ 2006- 2013）,the landscape patch shape complexity in the oasis was improved,both the oasis fragmentation degree and the patch connectivity degree were decreased,and the landscape heterogeneity was increased. The development trend of landscape fragmentation of the oasis was mainly affected by the development trend of landscape fragmentation in the Huqu region. After implementing the comprehensive management,an initial success of ecological regeneration was achieved,but the land desertification in the Quanshan region and the land salinization in the Huqu region were still serious. The change of landscape index on oasis scale and landscape scale was obviously different,which revealed that there was an obvious scale effect of landscape index. Water condition is a fundamental factor of driving the landscape pattern evolution,and the comprehensive management is clearly the development direction of changing the landscape pattern.