Methods to quantify the pedodiversity of 1 km2 areas — results from southern African drylands

When describing soil variability of a given area, pedodiversity measures are used as an integrative index for soil information and comparative diversity analyses. This paper compares different methods to derive pedodiversity indices based on a consistent data set of field and laboratory soil data of 16 dryland areas (1 km2 each) in southern Africa.Three approaches to quantify pedodiversity indices are compared: i) Taxonomic classification using WRB soil units, ii) Parametric classification using ‘soil eco-types’ — a strictly variable-based classification method, and iii) Variable space pedodiversity with direct use of variable values for the calculation of ‘environmental envelopes’ as an approach with convex hull algorithms.The meaning of all approaches was tested by correlating the pedodiversity indices with the biodiversity of the identical areas (diversity of higher plants). Irrespective of the methodological approach, correlations between the pedodiversity and the statistically significant biodiversity became apparent (p < 0.015…< 0.0001). Highest values of r2 = 0.83 occur in the variable space approach calculated based on four variables. In conclusion, the variable space method provides a powerful tool for creating a diversity measure which is neither affected by class size and limits nor by autocorrelation patterns.