My research is focused on spatial interactions in ecological systems, in particular among herbivorous insects on oak, among dung beetles and among insects of the high Arctic. During the last decade, I have been especially interested in how the relative role of bottom-up and top-down forces vary in space, and in how spatial context may affect the local interplay between herbivores and plants. While much of classical herbivore-plant ecology has been focusing on the role of local host plant quality as a determinant of herbivore densities, my colleagues and I have been able to partition spatiotemporal variation in host plant quality into different hierarchical levels, to show that variation among host plant individuals is frequently secondary to variation at other levels, and to ascribe regional patterns in herbivore distribution and abundance to spatial population processes beyond the previous top-bottom paradigm. In addition to showing effects on ecological population dynamics, we have also demonstrated how spatial context affects microevolutionary processes such as local adaptation. These insights help identify how and why human modification of the landscape may affect interactions among species.
In recent research, I have increasingly turned from plant-herbivore relations to interactions among multiple trophic levels. Here, I use quantitative food webs as descriptors of interaction structure. As key initiatives, I address general patterns across multiple local food webs, and link food web structure to food web functioning.
I conducted my PhD in the Metapopulation Research Group (MRG) between 1995 and 1999 as supervised by Ilkka Hanski. I then shared my post doc period between Helsinki and Alberta, Canada , where I worked in the group of