While I was trained as a plant biologist and ecologist, already during my PhD in France, I started to work on fungi and mycorrhiza, and after my coming to Germany I became a soil ecologist. Today, my main interest in research is to relate diversity of soil microorganisms (fungi and bacteria) to soil functioning, plant diversity and land use intensity in the context of the accelerated global change. A second field relates to the mechanisms behind the interplay between tree development and their multitrophic interactions.