摘要
选取 4个斑块形状指数 (斑块的周长面积比 SI1、斑块周长与等面积的圆周长之比 SI2和两个斑块分维 SI3和SI4 )并借助 GIS软件 ARC/ INFO对北京地区植被景观中的斑块形状进行分析 ,又对这四个形状指数进行了 Pearson相关分析和 Spearman秩相关分析。结果表明 ,SI1与 SI4、SI2与 SI3两两之间均呈显著的正的秩相关 ,SI1与 SI2、SI2与SI4、SI3与 SI4两两之间均呈显著的负的秩相关。因此 ,这些指数之间在很大程度上存在着信息重迭。但考虑到 SI2不受测量单位的影响 ,是一个值得推荐的形状指数 ;SI1虽说受测量单位的影响 ,但没有本质上的影响 ,只不过放大或缩小一定的倍数 ,也是一个比较好的形状指数 ;SI3和 SI4都受测量单位的影响 ,且有本质上的影响 ,不是很合适的形状指数。相对来说 ,各森林类型的 SI1都比较大 ,而各灌丛类型的 SI1都比较小 ,说明前者斑块的单位面积中的边界数量多 ,后者斑块的单位面积中的边界数量少 ;同时 ,SI1随斑块面积的增大而减小 ,这说明斑块越大 ,单位面积中的边界数量越少。72个斑块类型中 ,绝大多数森林类型、果园类型和水体斑块的形状指数 SI2值都比较小 ,其它类型的 SI2值一般都比较大 ,这说明前者的斑块形状比后者更紧凑 ;同时 ,SI2随斑块面积的增大而增大 ,这说明斑块越大 ,?
Four patch shape indices,which include ratio of perimeter to inner area of a patch( SI 1),ratio of patch perimeter to the perimeter of a circle with equal area with the patch( SI2 ),and two fractal dimensions of a patch( SI3 and SI4 ),were chosen to analyse the shape of patches in the vegetation landscape in Beijing using GIS software,ARC/INFO.The correlations among the four indices were analysed with Pearson correlation coefficient and Spearman rank correlation coefficient.The results show that significant positive rank correlations exist between each pair of SI1 and SI4 ,and SI2 and SI3 ;significant negative rank correlations exist between each pair of SI1 and SI2 , SI2 and SI4 ,and SI3 and SI4 .Therefore,there exists much information overlap among the four indices. SI2 is believed to be the best one among the four indices considering that SI2 is not affected by measurement units(MU).Although SI1 is affected by MU,the effect is superficial and not essential,which only amplifies or lessens for some multiple. SI3 and SI4 are all affected by MU,and the effect is essential.Thus,they are not recommendable in application. SI1 values are big for forest types,and they are small for shrubland types. SI1 becomes smaller and smaller as the patch becomes bigger and bigger.Therefore,the bigger the patch,the less the edges per unit area for the patch.The results also show that SI2 values of the patches for most types of forest,orchard,and water are smaller than those for other types.It is indicated that patch shape of the former types is more compact than that of the latter ones.Meanwhile, SI2 increases with patch area.Thus,the smaller the patch,the more compact it is.
出处
《生态学报》
CAS
CSCD
北大核心
2000年第4期559-567,共9页
Acta Ecologica Sinica
基金
国家自然科学基金项目!(10 0139770131)
中国科学院特别支持项目!( STZ-1-17)的资助
关键词
植被景观
斑块形状
形状指数
相关分析
GIS
vegetation landscape
patch shape
shape index
correlation analysis
geographical information system(GIS)
