Summary:

This paper analyzed seasonal dynamics of mite (Acari) aggregations, with particular attention to oribatid mites (Oribatida), in two different substrates intended for soil regeneration - shredded forest litter from Scots pine forest and pine wood chips. The study was conducted in the years 2011-2012, on microplots established within a belt of trees in a nursery in Białe Błota (Bydgoszcz Forest District). To maintain optimum moisture content, the microplots were hydrated by micro sprinklers as per the guidelines and schedule for the irrigation of nurseries, and mean soil moisture was kept at the level of 5.1-9.9 %. The mites were classified into orders and oribatid mites into species or genera, with regard to juvenile stages. A total of 4,142 mites were determined, including 2,939 oribatid mites.
Mite density in the shredded forest litter, intended mainly for soil inoculation with edaphon, was similar in the initial and final period of the study. Mite density in the pine wood chips, intended for mulching degraded soils and providing optimal conditions for mesofauna development, increased over two years of the study. Oribatid mites were the most abundant mites in the analyzed samples. Mean number of their species s in the forest litter was comparable at the beginning and at the end of the study cycle. In the pine chips, the differences in species abundance between the first and second year were significant. Oribatid mites most frequently observed in both substrates included Chamobates schuetzi, Oribatula tibialis and Tectocepheus velatus.