We are a subgroup of the Environmental Change Research Unit ECRU, working in the Ecosystems and Environment Research Programme at the University of Helsinki. Our primary interest is to understand how plant and decomposer communities interact in terrestrial ecosystems, how herbivore communities can manipulate this interaction and how these interactions together control the functioning and climatic responses of terrestrial ecosystems.

The decomposers depend on the carbon provided by plants through root exudation and litter production, but also transform nutrients from dead organic matter into forms that are available for plant uptake. The herbivores can intrude on this interaction by affecting plant growth, root carbon allocation and the quality of plant litter. As primary production in terrestrial ecosystems is mostly limited by nitrogen availability, our ultimate interest is to understand how the different interactions and mechanisms control terrestrial nitrogen cycling.

Climate warming will heavily impact northern areas. We are currently testing how dominant plant species, such as Betula trees and shrubs, respond to warming in northern ecosystems and whether their responses can be controlled by herbivore and pathogen pests. Also here, we aim at understanding how the responses of plant communities, primary production and plant-herbivore interactions cascade into changes in ecosystem functioning. Another active branch of research is to reveal how plants and soils are linked in the Arctic tundra and northern peatlands and how these links in turn control greenhouse gas fluxes and their response to climate warming in these environments. To strengthen our Arctic research, we are involved in Arctic Avenue, a spearhead research project between the University of Helsinki and Stockholm University.

Genetic variation of tree populations has a central role in our studies. We are particularly interested in the variation in tree herbivore resistance, litter decomposition and nitrogen cycling. In our field experiments, we aim at revealing how climate change could affect ecosystem functioning by affecting the genetic structure of tree populations.