The impact of different urban conditions on structural characteristics of oribatid mite communities

Abstract

Changes in the structure of oribatid mite communities were studied at six urban sites located in Bratislava, Slovakia (Central Europe). These differed in pattern and in the intensity of human impact. Soil samples were taken from each site at monthly intervals for a period of two years. A total of 139 species were identified, of which 64.8% occurred at the control site. Low numbers of species (18–26 spp.) were found at sites characterized by high anthropogenic pressure. The percentage of oribatid mites in acarocoenoses declined (in favour of other mite groups) at sites altered from their original biotope and influenced by permanent human intervention (from 70% to less than 25%). The highest abundance of mites (976.9 ind./dm2) was recorded at an urban site, where the oribatid mite percentage was only 21.2%. Species typical of wet forest and meadow habitats were found at sites with suburban and ruderal characteristics, where vegetation cover attenuates the heat island effect, whereas mainly xerothermophilous and eurypotent species formed oribatocoenoses in urban sites. Urban conditions resulted in distinctly lower values of diversity, species richness, and equitability. The species Epilohmannia cylindrica, Microppia minus, Oribatula tibialis, Protoribates capucinus, Rhysotritia ardua and Ramusella insculpta common in the European cities were recorded also in this study.