[目的]分析确定兰州市景观格局的最适合粒度,为生态安全格局的构建提供科学依据.[方法]通过地理信息系统(ArcGIS)识别与划分土地利用斑块;等权叠加单因子影响因素并使用夜间灯光数据叠加修正确定综合生态贡献斑块;采用景观格局分析软件(Fragstats)在景观水平上确定并分析21个景观指数对粒度变化的响应程度.[结果]景观格局指数对粒度变化的响应大体呈现3种趋势:1)效应曲线与函数拟合度高,无明显拐点.2)效应曲线增幅较缓,存在明显拐点.3)效应曲线变化幅度强烈,但整体变化趋于增长或下降,存在明显拐点.[结论]分析得出土地利用类型斑块和生态贡献等级斑块的第一尺度域分别为80～120 m和50～160 m.综合分析得出适合兰州市景观分析的粒度为80 m.
Granular effect of land use landscape pattern index in Lanzhou
[Objective]To determine the most appropriate granularity to analyze the landscape pattern of Lanzhou City,and to provide a scientific basis for the construction of the ecological security pattern.[Method]Identification and delineation of land use patches using Geographical Information System(Arc-GIS);Equal weighting of superimposed single factor influences and correction for night light data superim-position were used to determine comprehensive ecological contribution patches.Landscape pattern analysis software(Fragstats)was used to determine and analyze the response of 21 landscape indices to changes in granularity at the landscape scale.[Result]The response of the landscape pattern index to changes in granu-larity showed three trends:1)the effect curve and function fit were high,and there was no obvious inflection point.2)The slope of the effect curve is slow and there is an obvious inflection point.3)The effect curve changes strongly,but the overall change tends to increase or decrease,and there are obvious inflection points.[Conclusion]The first scale domains of land use type patches and ecological contribution grade patches were 80～120 m and 50～160 m respectively,and the comprehensive analysis showed that the appro-priate granularity for landscape analysis in Lanzhou City was 80 m.
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