Abstract: We used landscape diversity index (H),dominance index (DI),fractal dimension (D) and modif ied fractal dimension(Dm) to compare the spatial pattern of landscape between the low salt area(LS) andthe high salt area(HS) in Linze County,Gansu Province.The analyses on the spatial pattern of landscapeas a whole showed that H value rose and DI,D and Dm value reduced with the increase of the total saltcontent of soil: It indicated that soil salinization dwindled the difference of area and simplified the shape andspatial relationship among the different types of patches.The Dm was a more accurate and comprehensiveindex to describe the spatial pattern of the salinized grassland in Linze County according to the comparisonwith H,DI and D.The analyses on the spatial pattern of all patches showed that D value of the same typeof patch was higher in LS than in HS.It reflected that the high total salt content in soil decreased the shapecomplexity of plant comrnunities.From LS to HS,the area and Dm value of the communities,which domi-nant species being low salturesistance,reduced when that of the communities which dominant species beinghigh salt-resistance, reduced when that of communities which being apart from grazing increased.Theabove indicated that the spatial pattern and its variation were not only affected by soil salinization,but alsoprobably by human activity.

Key words: Soil salinization, Spatial pattern of landscape, Landscape diversity, Fractal analysis, Grazing

摘要： 采用景观多样性指数、优势度指数、分维数和修改分维数等指标,分析和比较临泽盐渍化草地轻盐区和高盐区的景观空间格局。区域景观空间格局分析结果表明,随着土壤全盐含量的增加,多样性指数随之增加,而优势度指数、分维数和修改分维则降低。说明在土壤盐渍化过程中,缩小了不同斑块间面积的差异,导致斑块形状和空间关系趋于简单。在描述临泽盐渍化草地的景观空间格局方面,修改分维数与景观多样性指数、优势度指数和分线数相比,是一个较为准确和全面的综合指标。对斑块的景观空间格局分析结果表明,同一斑块类型在高盐区的分维数普遍低于轻盐区,说明土壤全盐含量升高使斑块形状的复杂性降低。从轻盐区到高盐区,优势种的耐盐性相对较弱的群落面积减少,并且与周围斑块之间的空间关系趋于简单。与此相反,以相对耐盐植物为优势种的群落面积增加,与其它斑块之间的空间关系复杂化。随着土壤全盐含量的升高,与放牧关系密切的群落面积减少、空间格局多样性程度降低,而与放牧关系疏远的植物群落,其变化趋势恰恰相反。上述研究结果表明,盐渍化草地空间格局的变化既有土壤盐渍化的作用,又有人类活动的影响。

关键词: 盐渍化, 景观空间格局, 景观多样性, 分维分析, 放牧