Gelashvili D B, Iudin D I, Rozenberg G S, Iakimov N V
Zh Obshch Biol. 2007 May-Jun;68(3):170-9.
Applications of the fractal to describing the species structure of communities are discussed. Fundamental notions of fractal geometry are explained in the first part. The problem of applying the concept of fractal to describe the spatial allocation of particular species and of community as a whole is reviewed in the second part. In the final part, the usage of the selfsimirity principle for analyzing community organization is substantiated, and evidence of the fractal structure of biocenoses is presented according to Whittaker's concept of alpha diversity. It is shown that community is characterized, as a fractal object, by scale invariance, by power function relationship between the number of structural elements of the community (individuals, populations, species) and the scale (sampling effort), and, finally, by fractional value of the power (fractal dimension). Power function is the formula the takes into account the share of rare species, or species represented by a single individual. providing for no saturation of the function f(x). This formula also does not contradict the A.P. Levich's "rule of ecological non-additivity" and, lastly, allows the application of fractal formalism to characterize the species structure of a community. It is concluded that the mathematical image of species richness is a monofractal, i.e., a set characterised by only one parameter, fractal dimension. Thus, the species structure of a community (as well as the pattern of its spatial allocation) displays self-similarity and is a fractal.
讨论了分形在描述群落物种结构中的应用。第一部分解释了分形几何的基本概念。第二部分回顾了应用分形概念描述特定物种和整个群落空间分布的问题。在最后一部分,证实了自相似性原理在分析群落组织中的用途,并根据惠特克的α多样性概念给出了生物群落分形结构的证据。结果表明,群落作为一个分形对象,具有尺度不变性,群落结构元素(个体、种群、物种)数量与尺度(采样强度)之间存在幂函数关系,最后具有幂的分数值(分形维数)。幂函数公式考虑了稀有物种或由单个个体代表的物种的比例,函数f(x)不会饱和。该公式也不与A.P.列维奇的“生态非加和性规则”相矛盾,最后允许应用分形形式来表征群落的物种结构。得出的结论是,物种丰富度的数学图像是一个单分形,即仅由一个参数分形维数表征的集合。因此,群落的物种结构(以及其空间分布模式)表现出自相似性,是一个分形。