毛竹无性系种群空间分布格局及其分形特征

Spatial Distribution Patterns and Fractal Characteristics of Phyllostachys heterocycla cv. pubescens Population

毛竹(Phyllostachys heterocycla cv.pubescens)是主要通过地下茎无性繁殖的散生竹类,研究其种群空间分布格局,可以揭示毛竹种群的空间生长特性和生态适应机制。本文利用分形理论中的计盒维数和信息维数,对毛竹无性系种群空间分布格局的分形特征进行了研究,结果表明:种群空间分布格局存在分形特征,种群计盒维数在1.449 4-1.596 6之间,信息维数在0.432 2-0.468 7之间。毛竹无性系种群的计盒维数值接近最大理论值2,总体对生态空间的占据能力较强。毛竹种群格局分布类型表现为随机分布,其信息维数与种群分布格局的聚集强度不相关。运用扩散系数法分析也表明,毛竹种群格局的分布表现为随机性,但各样地之间的聚集强度指数仍存在一定的差异,种群格局聚集强度与分株种群的斑块特征和水平空间分布情况有关。

The Phyllostachys heterocycla cv. pubescens primarily propagates asexually through rhizomes. The study of the spatial distribution pattern is conductive to reveal its spatial propagation characteristics and ecological adaptation mechanism. Based on the fractal theory, the indicators of box-counting dimension and information dimension were used to analyze the fractal features of the spatial distribution pattern of the bamboo clonal populations. The results showed that population spatial distribution pattern did appear fractal characteristics, the box- counting dimensions ranged from 1. 449 4 to 1. 596 6, and the information dimensions ranged from 0.432 2 to 0.468 7. This indicated that the Phyllostachys heterocycla cv. pubescens clonal population had a strong ability to occupy ecological space. The Phyllostachys heteroeyela cv. pubescens population distributed randomly, and its information dimension was not related to aggregation intensity. The diffusion coefficient also confirmed the random distribution pattern. Nevertheless,there were still differences in gathering strength index among different sample plots. In general, the aggregation intensity of population was related to patch characteristics and the horizontal spatial distribution pattern.