Sletvold lab: Our research

Population viability

Today, land-use changes are among the most immediate threats to many plant populations, and management actions mimicking traditional use are increasingly undertaken to conserve species. In most cases only short-term data constitute the basis for initiated actions, and the extent of potential interactions between management practices and temporal environmental variation is unknown. This is of particular concern in relation to climate change, since a further acceleration of habitat change is predicted in response to global warming. To examine effects of natural and human-induced environmental changes on population performance we combine long-term demographic monitoring in natural and managed field populations with experimental approaches targeted at the most uncertain life cycle transitions in orchid populations (germination and dormancy).

We also use controlled crosses and field germination experiments to integrate the effects of pollen limitation and inbreeding across the orchid life history. The goal is to produce knowledge that will underpin management decisions and future conservation strategies for several declining and threatened species. At present, we focus on three long-lived species that all are associated with the agricultural landscape, but differ in mating system, distribution pattern and conservation status: Dactylorhiza lapponica, Nigritella nigra and Gymnadenia conopsea. This project is in collaboration with A. Moen and D. I. Øien at NTNU, and J. P. Dahlgren and J. Ehrlén at Stockholm University.

Plant-pollinator interactions

Floral evolution is thought to be driven largely by interactions with pollinators, and the link between floral diversity and diversity in pollination mechanisms was made clear already by Darwin. Still, our knowledge of the strength and form of natural selection in the wild is limited, and we are lacking a quantitative understanding of the role of pollinators relative to other selective agents in shaping selection on floral traits.

In ongoing projects, we use field experiments to examine the degree of pollen-limitation and the strength, form and mechanism of pollinator-mediated selection on floral traits in the food-deceptive orchid Dactylorhiza lapponica and the rewarding orchid Gymnadenia conopsea, as well as potential costs of reproduction in these species. The aim is to quantify lifetime contribution from specific selective agents by integrating phenotypic selection gradients with demographic data. The project is a collaboration with J. Ågren at Uppsala University.