中尺度流域的景观格局分析--以湖北四湖流域为例

以湖北四湖流域为中尺度流域的代表，对流域九种景观类型657个斑块的形状、6种景观类型分离程度、四个分区及全流域的景观异质性进行了分析。结果表明：斑块伸长指数和形状系数是完全相关的，它们与周长／面积各自表达着形状复杂性的不同方面，有必要对其进行综合评价；四湖流域的不同类型的景观斑块形状有较大差异，分区间的斑块形状差异较小；湿地类型的斑块形状趋于简单，其中湖泊斑块形状员简单，非湿地类型的斑块形状趋于复杂，又以林地类型为员。这表明本地区的湿地，特别是湖泊，受到了更大的人类活动影响；湖泊斑块的分布最集中，居民点斑块的分布员分散，这不利于控制流域内的洪涝灾害；从流域的上游到下游，景观多样性和均匀度呈增加的趋势，景观破碎化程度呈下降趋势，这种景观异质性的空间差异反映了流域空间开发历史的长短和人类活动强度的差异。

ANALYSIS OF LANDSCAPE PATTERN FOR MIDDLE SCALE WATERSHED--A CASE STUDY OF SIHU WATERSHED IN HUBEI,CHINA

As an example of middle-scale watershed,the shape of657patches belonging to9landscape types,the dispersion of patches belonging to6landscape types,the landscape heterogeneity of4subareas and whole watershed,in Sihu watershed in Hubei,were investigated in the present study.Elongation index and shape co-efficient were completely correlated,they were independent to perimeter/area,so the shape coefficient or elonga-tion index and perimeter/area were the reflection of different characteristics of patch shapes.The comprehensive index was available to evaluate patch shape.There was much more differences among landscape types in Sihu watershed but little among subareas.The patch shape of wetlands appeared to be simple,while the lakes the simplest,and non-wetlands complexed,forest the most cemplexed.So we can consider the wetlands especially lakes were affected more by human activity.The distribution of lakes was the most centralized ,and residential was the most dispersive,The landscape diversity and evenness appear to increase,and fragementation went down from the higher reach to the lower of the watershed.The difference of landscape heterogeneity among the watershed space reflects the history of watershed exploitation and the intensity of human activities.