Summary:

The study was conducted in 2011-2012 by using litter bags on microplots in a forest soil under a canopy of trees, in optimal environmental conditions for most mites. The aim of the study was to analyze the colonization by mites of wood chips after application of two biopreparations containing cellulose-degrading bacteria. The experiment was conducted in the following variants: WC - control wood chips, WB I - chips after application of bacterial inoculum I (an unidentified G(-) rod-bacterium, Bacillus sp.) and WB II - chips after application of bacterial inoculum II (Streptomyces sp.). To maintain the optimum moisture level, the microplots were irrigated by means of microsprinklers. The highest average population density of mites in the two-year series of tests was found in the control chips: 42.28 individuals per 50 cm3. In the chips treated with the biopreparations, the density of these arthropods was lower, but the differences were not statistically significant. Dominant among the mites were mostly oribatid mites. Altogether, 34 species of oribatid mites were found in all the experimental variants. The most species (30) were found in the control variant, and fewer in the chips treated with the biopreparations - 27-26. Among the oribatid mites, Tectocepheus velatus was dominant, and quite numerous were such species as: Suctobelba sp., Oppiella nova, Gymnodamaeus bicostatus, Metabelba pulverulenta, Oribatula tibialis, Eniochthonius minutissimus. The study shows that the wood chips were colo-nized by oribatid mites gradually - in the first year there were variations in the size of individual populations, mostly at a low level. The process of colonization was accelerated considerably in the second year of the study, especially in the summer.