I am interested in the reciprocal interaction between plants and their natural enemies, parasitic fungi and insect herbivores.
I am interested in the interplay 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 in rising archipelagos and (2) focused on the role of global change (increased nitrogen availability and temperature) in the boreal forest landscape.
A more recent interest is to understand the various factors that has resulted in the dramatic changes in species composition that has taken place in Bothnian archipelagos.
Spatio-temporal patterns in rising archipelagos
The work is conducted in a Bothnian archipelago, Skeppsviks archipelago, 30 km east of Umeå, 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 yrs 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 possible role of global change in affecting these interactions has received increasing attention in recent years.
The work in the archipelago was initiated in the early 70´s and has ever since 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 Phalacrus substriatus.
The boreal forest landscape
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. I´m particularly interested in the role of various snowblight fungi.
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.
Long-term change in Bothnian archipelagos
My interest in the flora of Bothnian archipelagos started in the late 60´s. The changes in species composition have been remarkable and I have been increasingly interested to try to understand the causes.