Could soil granulometry and permeability drive the occurrence of the dune-dwelling ants from the genus Mycetophylax?

Abstract

Species distribution can be influenced by several biotic and abiotic factors. Physical soil properties, such as granulometry and permeability, can, therefore, be key determinant factors of the occurrence of ground-dwelling species. Here, we evaluate whether the physical properties of soil, such as granulometry and the resulting soil permeability, could drive nesting occurrence of the endemic psammophilous ants from the genus Mycetophylax and, in turn, their distribution. To accomplish this goal, we tested the hypothesis that variations in the granulometry and the resulting permeability (high or low D10 values) of beach soils contribute to explain the distribution pattern of dune endemic species from the genus Mycetophylax. We sampled sand soils from 26 beaches across the known distribution of the species along the Brazilian Atlantic coast. Sorting through seven mesh sieves, we determined the proportion of sand grain size of each sample and then calculated the effective diameter (D10). Therefore, we investigated the occurrence of the three ant species in relation to the soil permeability determined by D10. The spatial variation in sand grain size and its permeability across the beaches of the Atlantic coast is likely one of the contributors that influence the pattern of distribution of psammophilous ants such as Mycetophylax simplex, M. conformis, and M. morschi.