天然黄山松种群格局的分形特征——计盒维数与信息维数

采用计盒维数和信息维数对屏南和寿宁不同群落的天然黄山松(Pinus taiwanensis)种群格局的分形特征进行比较分析.结果表明,天然黄山松种群格局具有分形特征,其计盒维数值在1.299 8～1.862 6之间,不同群落的大小次序为Q3>Q1>Q2>Q4>Q7>Q8>Q5>Q6;信息维数值在1.205 7～1.863 7之间,大小次序是Q3>Q1>Q2>Q4>Q8>Q7>Q5>Q6,屏南天然黄山松近纯林黄山松种群的计盒维数和信息维数均高于寿宁混交林,计盒维数定量描述种群占据水平空间的能力和程度,信息维数揭示种群格局强度的尺度变化及个体分布的非均匀程度,分形维数值的高低与群落环境、种群密度、种群在群落中的优势地位、个体的聚集程度及幼树个体数量等相关.黄山松种群格局分形维数随海拔呈现上下波动变化,1 250～1 270 m是更适生的海拔范围.此外,黄山松种群格局的分形特征存在一定的尺度范围,其拐点尺度是分形范围的下限尺度.

Fractal Characteristics of Pattern of Natural Pinus taiwanensis Population--Box-counting Dimension and Information Dimension

The fractal characteristics of pattern of Pinus taiwanensis population in different natural community types in Pingnan and Shouning county was analyzed by applying box-counting dimension and information dimension.The results indicated that P.taiwanensis population in natural community had fractal characteristics;The box-counting dimension ranged from 1.2998 to 1.8626 and the order in different communities was Q3>Q1>Q2>Q4>Q7>Q8>Q5>Q6;The information dimension ranged from 1.2057 to 1.8637 and the order in different communities was Q3>Q1>Q2>Q4>Q8>Q7>Q5>Q6.The box-counting dimension values of P.taiwanensis population in natural and almost pure P.taiwanensis forest in Pingnan showed higher than the mixed forest in Shouning;Box-counting dimension quantified the spatial occupation capability and degree of the population,while information dimension reflected the scale variation degree of pattern intensity and disclosed the unevenness of individual distribution.The fractal dimension was related to community environment,the density of the population,dominant status of the population in community,the aggregated intensity of all individuals and the number of sapling individuals.The fractal dimension of natural P.taiwanensis took on fluctuation up and down as the altitude rose and 1250-1270 m were more befitting altitude to survival.In addition,the fractal characteristics of pattern of P.taiwanensis population possessed a certain scale and the scale of inflexion of point was the infimum.