Selfsimilarity of pedotaxa distributions at the planetary scale: A multifractal approach

Soil complexity and environmental heterogeneity may be cast in the framework of the theory of complex systems, and can be understood as a by-product of deterministic chaotic dynamics. Therefore, highly irregular patterns with so-called multifractal behavior should be common. Moreover, it has been found that pedorichness–area relationships conform to power-law models, which can be considered as a fingerprint of fractal geometry. Thus, selfsimilarity should be a generic property of spatial distributions of pedorichness. In this context we analyze the selfsimilar features of pedotaxa-abundance distribution at the planetary scale, from the point of view of multifractality, in order to characterize its complexity and its selfsimilar patterns as well as to provide pedodiversity indicators. We compute the singularity and Rényi spectra for the abundance distribution of pedotaxa for the five landmasses and the whole world from FAO Soil Database. Pedotaxa correspond to the second level of FAO units using the classification from 1974. Our analysis indicates that the complex behavior of pedodiversity distributions at the planetary scale follows a well-defined multifractal behavior. Multifractal parameters can be used as pedodiversity indicators and show promise for analyzing and characterizing the complexity of soil development at multiple scales. Therefore, multifractal analysis yields a unified framework that includes the common procedures to characterize diversity: taxa-abundance distributions and diversity indices.