Ecology and functioning of soil decomposer animals

Studies on soil ecology have been focusing on the long-term basis e.g. on how forestry and microplastics from agriculture affect diversity of soil animals, decomposition of organic matter and nutrient cycling. Results of these studies can help e.g. to guide human activities so that soil biodiversity and fertility are not diminishing.

We have been interested in how boreal coniferous forest soil and its biota respond to forest regeneration practices and harvesting of bioenergy. Soil decomposer organisms (soil animals and microbes) have an important role in the functioning of forest ecosystems. Decomposers affect soil structure and finally release nutrients from dead organic matter that are available for plants. Decomposer community in forest soil is very diverse, consisting of myriad different taxa of bacteria, fungi, protists, nematodes, microarthropods, enchytraeids, macroarthropods and earthworms. Decomposer communities of boreal forest soils are well buffered against environmental changes caused by forest harvesting and subsequent regeneration. However, effects of e.g. harvesting of logging residues and stumps on forest soil decomposer communities, forest nutrient and carbon dynamics and vegetation are still poorly known.

Our research has been aimed at determining whether forestry practices affect soil decomposers and vegetation at the site scale. We have examined e.g. how the decomposer animal community differs between stump-harvested and traditionally treated (clear felling followed by site preparation) areas. Our other questions have been: Do succession of vegetation and growth of tree seedlings differ between the treatments? Are there short-term differences in decomposition activity and nutrient mobilization between the stump-harvested and traditionally regenerated areas?

We are involved in the global Soil BON Foodweb project, which focuses on the structure of soil animal communities and the factors that influence community compositions, and harmonizes the research methods that are used in soil animal studies.

We are also studying in cooperation with the Finnish Environment Institute the occurrence of microplastics in agricultural soils, and how micro and nano-plastics affect soil organisms and ecosystem services in arable areas. Both laboratory and field experiments have been carried out with special focus on earthworms. The final aim is to deliver information for farmers, industries, regulators and policy makers to enhance the safety and sustainability in the use of agricultural plastics. The field and laboratory experiments have been part of the EU-funded Horizon 2020 project PAPILLONS (Plastics in agriculture: impacts, lifecycles & long-term sustainability).