My research is focused on interactions between plants and their natural enemies (parasitic fungi and herbivores) and how these interactions shape population dynamics and community structure. I have two main approaches (1) focused on spatio-temporal dynamics and (2) focused on the role of increased nitrogen availability and temperature (global change).
This work is conducted in a Bothnian archipelago, Skeppsviks archipelago, subjected to isostatic rebound (85 cm/century). This archipelago has about 100 islands that vary in age from young incipient islands to those that are more than 1 000 yr old. This ideally, and for some systems, represents a gradient of increasing temporal coexistence between host plants and their natural enemies, while other systems are more affected by species composition and abiotic factors. Our work addresses colonization and extinction processes of both host plants and their natural enemies and whether these interactions will result in reciprocal interactions between the involved organisms.
The work in the archipelago was initiated in the early 70:ies and has since around 1990 been focused on the role of bi- and tritrophic interactions. We utilize both annual monitorings, and various field- and glasshouse experiments.
Examples of two important study systems are:
Filipendula ulmaria – the rust fungus Triphragmium ulmariae – two chrysomelid beetles Galerucella tenella and Altica engstroemi.
Sedges, Carex spp. – their smut fungi Anthracoidea spp. – and the vector, the shiny beetle Phalcrus substriatus.
Most boreal plant communities are dominated by ericaceous dwarf-shrubs adapted to nutrient-limitation. These dwarf shrubs house a species rich flora of parasitic fungi which play a key role in structuring these communities. Our work primarily addresses how these interactions are affected by increased nitrogen deposition, and whether this will result in vegetation shifts, but we also address the effects of increased temperature and changed snow package.
This work was initiated in 1996 and we utilize long-term field experiments in nutrient poor forest and mire ecosystems in which we manipulate nitrogen availability, temperature and snow depth. The experiments are located in the Vindeln area, an area characterized by a low background deposition of nitrogen, which allow us to study initial vegetation responses of low doses.