Soil fauna of Finland: Acarina, Collembola and Enchytraeidae

This paper is a summary report of a study on the soil fauna of Finland, supported by the Ministry of Environment, in the framework of the Finnish “PUTTE-Project” (Research Programme of Deficiently Known and Threatened Forest Species). Thematerialwas collected systematically from 15 different habitat types in eleven sampling areas with geographical coverage of the country

Root trenching: a useful tool to estimate autotrophic soil respiration? A case study in an Austrian mountain forest

We conducted a trenching experiment in a mountain forest in order to assess the contribution of theautotrophic respiration to total soil respiration and evaluate trenching as a technique to achieve it. We hypothesised that the trenching experiment would alter both microbial biomass and microbial community structure and that Wne roots (less than 2 mm diameter) would be decomposed within one growing season. Soil CO2 eZux was measured roughlybiweekly over two growing seasons. Root presence and morphology parameters, as well as the soil microbial community were measured prior to trenching, 5 and 15 months after trenching. The trenched plots emitted about 20 and 30% less CO2 than the control plots in the Wrst and secondgrowing season, respectively. Roots died in trenched plots, but root decay was slow. After 5 and 15 months, Wne root biomass was decreased by 9% (not statistically diferent)and 30%, (statistically diVerent) respectively. When wecorrected for the additional trenched-plot CO2 eZux due to Wne root decomposition, the autotrophic soil respiration rose to »26% of the total soil respiration for the Wrst growing season, and to »44% for the second growing season.Soil microbial biomass and community structure was not altered by the end of the second growing season. We conclude that trenching can give accurate estimates of the autotrophic and heterotrophic components of soil respiration, ifmethodological side eVects are accounted for, only

Decomposer community in boreal coniferous forest soil after forest harvesting : mechanisms behind responses

Effects of different forest regeneration methods on decomposer animals in boreal coniferous forest and the mechanisms behind the responses were studied in three field experiments and a laboratory experiment. The study focused mainly on enchytraeids, collembolans and microbes. In addition, decomposition, soil nitrogen availability and primary production were measured. In the first experiment, treatments with untreated controls were selection felling, gap felling with and without harrowing, retention felling (tree patches retained) and clear felling. The other field experiments were established in untreated forest to exclude major effects of changes in microclimate. The studied factors were exclusion of mycorrhizal connections (trenching), exposure of mineral soil (sod cutting) and addition of felling residues. The functional role of enchytraeids in different soil layers was studied in the laboratory experiment. Clear felling decreased fungal biomass and increased enchytraeid numbers. Microbial respiration decreased and community structure of microbes (PLFA pattern) changed as compared with the control. In addition, some litter dwelling macroarhropods (certain beetle species, spiders, scale insects) decreased in numbers. Responses in small gaps were similar to those in clear fellings, but smaller, whereas selection felling had no influence on the studied organisms. Trenching and sod cutting induced similar changes to measured variables as observed in clear fellings. Felling residues (slash) had no effect on soil organisms. Effects of enchytraeids on nitrogen mineralisation were dependent on soil layer and resource quality. It was concluded that despite some responses, the decomposer community is well buffered against initial changes caused by forest harvesting