西藏昌都地区云杉群落空间分布格局的分形分析

Fractal Analysis on Spatial Distribution Pattern of P.asperate Communities in Changdu, Tibet

基于分形几何的计盒维数研究了西藏昌都地区天然云杉群落空间分布格局 ,结果表明 ,云杉群落空间分布格局均具有统计自相似性 ,在不同的尺度范围内具有不同的空间分布格局 ;而计盒维数定量地表征了云杉群落占据空间程度及其尺度变化规律 ,其个体聚集尺度为2 .0m ;各类云杉群落空间格局具有较低的计盒维数 (均 <1.3) ,表明其空间占据程度较低 ,这与其所处高寒的自然环境有关 ;云杉群落空间占据能力依次为云杉—桦类 >云杉 -杨类 >云杉—柏类 >云杉—栎类 >云杉纯林。

Based on box-counting algorithm ,the spatial distribution pattern (SDP) of P.asperate communities in Changdu, Tibet is studied in the paper.The results show that SDP of the communities exhibits statistical self-similarity with scale dependency, and box-counting dimension of SDP quantifies the scale variation degree of P. asperate occupying ecological space.The scale of single cluster is about 2.0m. With relatively low dimension ,which is generally less than 1.3, P.asperate has a poor ability of space occupying in the area, where is of alpine with cold weather . With a relatively higher box-counting dimension , mixed P. asperate community has a powerful capability of space occupying and environmental resource utilizing than that of pure P. asperate forest.