The study was conducted in the years 2011–2012, in a forest nursery in Białe Błota (Bydgoszcz Forest District). The experiment was established in a 20 m wide belt of trees within a 110 years old stand growing on mixed fresh coniferous forest site. Litter bags containing hardwood and pine wood chips were placed on mineral soil of microplots and covered with a 5 cm layer of litter. The pattern of chips colonization differed between mites belonging to different orders. Predatory Mesostigmata colonized hardwood chips gradually but they were present in high numbers in pine chips from the beginning of the study. Abundance of Actinedida fluctuated within the two-year study cycle. Contrary to that, oribatid mites, which were a predominant mite type, colonized both types of chips gradually, while preferring the pine ones. At the end of the study, the structure of mite communities and mite abundance in pine chips were more similar to forest soil than in hardwood chips. The experiment demonstrated that pine chips provided most oribatid mites with more favorable living conditions than hardwood chips, as they were colonized at a quicker rate and by a greater number of species. The most abundant oribatid mite in both substrates was a eurytopic Tectocepheus velatus that showed no clear preferences towards either of the substrates. Majority of oribatid mites, e.g. Oppiella nova, Metabelba pulverulenta, Oribatula tibialis, Chamobates schuetzi, Galumna lanceata, preferred pine chips. The only species with clear preference for hardwood chips was Eniochthonius minutissimus. A comparison of usefulness of hardwood and pine wood chips in revitalization of degraded soils based on bioindication approach indicated higher suitability of pine chips that are also more available in Polish forests.
Andrzej Klimek, Stanisław Rolbiecki and Roman Rolbiecki
Intensively used forest nurseries are characterised by degradation processes that lead to a drop in the quality of seedlings. The main reason of this problem is a decrease in biological soil diversity. Therefore, an attempt of nursery soil enrichment by introducing ectohumus – as compost and fresh litter – from the pine forest was carried out. The research was carried out in 2009–2011 in the Bielawy forest nursery near the city of Toruń, Poland. The objective of the study was to determine the impact of organic fertilisation (compost made up of forest humus) and mulching using fresh ectohumus on the density and community composition of Acari mites and on species composition of oribatid mites (Oribatida) in the nurseries of silver birch and Scots pine. Mites, especially oribatid mites, were treated as bioindicators of soil biological activity. Research has shown that mulching using fresh ectohumus caused a multiple increase in the density of mites, especially in saprophagous mites Oribatida. Oribatid mites were clearly more numerous in birch cultivation than in that of pine. Overall, 27 species of oribatid mites were found. Mulching resulted in a significant growth in species diversity in both cultivations. The most numerous oribatid mite in the area under the study was Oribatula tibialis. This species was present in all plots and showed clear preference for birch cultivation. Tectocepheus velatus and Oppiella nova, common and known to be present in a variety of environments, were slightly less numerous.