The Soil Chemical Properties Influencing The Oribatid Mite (Acari; Oribatida) Abundance And Diversity In Coal Ash Basin Vicinage

The samples of two technogenic sediments (MOS, coal ash sediment; MOD, a mixture of ash and natural soil) and two natural soils (MOM, meadow; MOF-forest; both Cambisol Dystric) in the vicinage of the coal ash basin were studied. We evaluated risk element concentrations and select-ed chemical and microbiological parameters to determine their influence on the community structure of Oribatida. High concentrations of various toxic elements, alkaline pH, and low hu-midity negatively affected the abundance of oribatid mites. The microbial indicator values showed that the soil microbial community formed in technogenic sediments could effectively use organic carbon. However, considering the wide C/N ratio of the substrates, the process of soil organic matter (SOM) decomposition was slowed down, and thus nutrients were less available for the mites, which could be among the reasons why we did not find any individual of oribatid mite in MOS. In MOD, however, we found representatives of three species, but only Tectocepheus velatus sarekensis established an abundant community at the highly contaminated site. Anthropogenic pressure resulted in the selection of r-strategists, which became dominant and reduced the whole community's species' diversity. Therefore, we consider it a suitable indicator of improper human intervention in the ecosystem.