Multifractal and joint analysis of soil arthropod diversity in the Brazilian Savanna

Abstract

Soil fauna organisms participate in a series of processes that benefit the physical and chemical soil properties; however, little is known about their spatial variability and scale. This study aimed to characterize the spatial variability of soil fauna from multifractal and joint multifractal analysis in Brazilian Savanna areas. Pitfall traps collected soil fauna in two Savanna formations (dense Savanna and typical Savanna) in two transects with 128 points. Organisms were identified and classified into functional groups (Microphages, Pollinators, Predators and Social), and then Ind trap−1 day−1 (number of individuals per day in the sample) and Richness were determined. Data were analyzed using multifractal and joint multifractal analysis, and the scale indexes f(α,β) were generated for the singularity indexes of α(q,t) and β(q,t), considering Ind trap−1 day−1 and Richness as predictive variables. A total of 3456 and 1629 individuals were collected from T1 (dense Savanna) and T2 (typical Savanna), respectively. The singularity spectrum for soil fauna showed the greatest difference in dimensions D−10 –D10 for the functional group Pollinator (D−10 –D10 = 0.936) in T1 and for Social (D−10 –D10 = 0.620) in T2, reflecting more heterogeneous systems. The joint multifractal dimension showed a high correlation between Ind trap−1 day−1 and the functional groups (Pollinators, Predators, and Social) in T1, demonstrating how phytophysiognomy of this experimental plot (dense Savanna) favors the presence of these organisms and reflects the spatial correspondence of the measurement values along the geometric support. Abundance of organisms (Ind trap−1 day−1) and Richness were promising variables to represent the set of relationships with the functional groups of soil invertebrate fauna. In general, multifractal analysis using abundance and Richness can assist in decision-making focused on conserving Savanna areas.