摘要
应用辽宁省1997～1998年的TM5影像数据,编制了景观类型图,以78个县市区为单位,分割成78个景观,共计算39个景观格局指数,对它们进行了相关分析.总面积是最基本的景观指数,它决定景观总边界长度、斑块数、类型密度等基本指数,同时与多个指数有显著的相关关系(相关系数绝对值大于0.75).形状指数的独立性强,极少数指数与其它指数有显著的相关关系;多样性指数和蔓延度指数之间信息重复量最多,都表示景观的异质性,但多样性指数以面积百分比表示景观异质性,而蔓延度指数以类型之间相邻边界的百分比表示景观异质性.研究发现,如果两个指数之间存在显著的相关关系,而由它们两个构成的指数与它们之间没有显著的相关关系.如果指数平均值之间存在显著的相关关系,则它们的变异系数之间不存在显著的相关关系.景观指数间的相关系数不仅与景观格局本身有关,还与空间尺度,分类系统、计算公式及其参数、计算单元和生态学意义关系密切.指数之间影响因子的相同之处越多,它们之间存在显著相关关系的概率越大.
Numerous landscape metrics have been developed during last three decades to describe and quantify complex landscape patterns and link landscape patterns and ecological processes. This generates a great deal correlated and redundant information if all of the indices were calculated. Thus, it is necessary to identify the correlated landscape metrics and to find out the relationships among them. In our study, the 1999 Landsat imageries of Liaoning Province of China were classified into 16 cover types, the entire study area was clipped into 78 landscape maps according to the county or city boundaries. Thirty nine landscape metrics were calculated for each map, including area, perimeter and density, shape, diversity and contagion. F-Test showed that the correlation coefficient greater than 0.28 is significant at p = 0.01 in while the empirical study showed that the correlations between indices exist when correlation coefficient is greater than 0.75. Thus, we considered strong correlations between the landscape indices exist only when the correlation coefficient is greater than 0.75. The result showed that total area is the most basic index within landscape metrics. It correlated with many landscape metrics such as total edge and number of patches in the landscape. Shape metrics are more independent than other groups. Only fractal dimension （log） and mean shape index correlated significantly. Many diversity metrics correlated among themselves, especially the Shannon and Simpson indices. However, Shannon indices are more sensitive to the minor cover type and Simpson indices are more sensitive to common cover types in landscape. Furthermore, Simpson indices are more sensitive to patch density, edge density and average patch area than Shannon indices. Diversity metrics use the proportions of cover types and number of classes to describe the landscape diversity, and contagion metrics use the adjacency matrix to describe the landscape edge diversity, therefore diversity indices are often correlated with contagion indices. Diversity and contagion indices show different aspects of heterogeneity of the study landscape. When an index correlates with another index, the coefficient of variation does not correlate with each other. For example, mean shape index correlates with mean fractal dimension, but their coefficients of variation are independent. Once two basic metrics are correlate with each other, the index consists of two of them are not correlated with the two basic metrics significantly. For example, the total area and number of patches correlate each other, but the patch density does not correlate with them strongly. Finally, the correlation coefficients among landscape metrics were influenced by the landscape patterns, spatial scales, classification systems, mathematical equations, units and ecological meanings. The more common influencing elements above mentioned are in two landscape metrics, the higher probability of strong correlation are among them.
出处
《生态学报》
CAS
CSCD
北大核心
2005年第10期2764-2775,共12页
Acta Ecologica Sinica
基金
国家重点基金资助项目(40331008)
国家重点基础研究发展规划(973)资助项目(2002CB111506)~~
关键词
景观格局指数
相关系数
相关分析
landscape metrics
correlation coefficient
correlation analysis
