## 1 Introduction  
Global changes in climate and land use are affecting the biodiversity of soil arthropods in many ecosystems [1]. Orbitaid mites represent species-rich and highly abundant soil mites inhabiting the soil's upper layers [2]. There is increasing interest in their reaction to environmental conditions such as metal pollution because of their essential role in detrital food webs. They are actively involved in the soil decomposition process, increasing soil fertility by recycling nutrients out of dead organic matter. The low reproduction and long life-cycle rates suggest that orbitaid mites may be sensitive to environmental change [3]. They are not passive inhabitants of ecosystems; instead, they are strong interactors. Despite being generally sensitive to disturbance, orbitaid mites show a considerable variation in sensitivity among taxonomic groups. The various scientific papers declare that the number of species is declining toward the more significant disturbance, and, at the same time, the composition of their entire community is changing [4, 5]. The large number of factors determine the distribution and abundance of soil mites. Among the abiotic factors, soil pH and soil organic matter (SOM) represent the most significant drivers concerning soil pH variation on soil arthropods' presence [6, 7] and arthropods' role in SOM degradation. Highly increased levels of metals, wide C/N ratio, and pH values were recognized as the structuring forces that influence the distribution, diversity, and richness of orbitaid species, whereas the soil reaction (pH) influences these differences fundamentally [8]. Changes in the value of the soil reaction mostly come from pollution from industrial production and mining. Its value affects the soil's chemical, physical, and biological properties and the solubility of organic carbon and increases the bioavailability of various toxic elements,mainly metals. Soils around heating power plants are often enriched in metals due to ash blowout of refuse heaps, and toxic metals tend to accumulate in high concentrations in the topsoil near point sources [9]. Orbital mites proved to have a high capacity to colonize postindustrial dumps [10]. With an increasing metal load of the soil, sensitive species may be replaced by resistant ones without changing the total number of mites. One of the critical reasons for reducing the abundance and species' richness of Orbitadta at highly contaminated sites may be explained by toxic effects through the uptake of toxic metal-loaded microorganisms, especially fungi [11]. In general, orbidatids and their communities are relatively tolerant of toxic metal exposure [12; 13]. Many studies have measured their responses to environmental pollution at the community level [14; 15]. The studies proved that heavy pollution exposure decreases both abundance and species' diversity, but species vary in their sensitivity to pollution, and some species may even benefit from moderate pollution levels [14; 16]. Orbitadids includes some species with resistance to metals to maintain their populations in even highly contaminated soils [15; 16; 17]. The findings mentioned above suggest that the opioid mites have a great potential to be used as bioindicators of changing soil environment. Therefore, it is crucial to understand how the mite community responds to ongoing soil ecosystems' changes. Soil microarthropods play a vital role in the nutrient cycle due to the litter's fragmentation, increasing the microbial action area and stimulating microorganisms' growth [18]. They accelerate the circulation of elements within ecosystems, either directly or indirectly, by stimulating soil microbes and contributing to soil fertility maintenance [19]. Their essential role in litter decay as detritivores suggests that any change in their community structure in response to global environmental change is likely to have further consequences for ecosystem functioning. The hypotheses were as follows:  
1.