Arctic and Alpine Ecology

Impacts of hemiparasitic plants on plant community dynamics under global change

Patrick Kuss
Hemiparasitic plants are known to negatively impact total biomass production of grasslands. At the same time they may facilitate species co-occurrence through mediating competitive hierarchies among species. In a set of experiments we aim to elucidate the functional role of hemiparasites in species co-occurrences under global change scenarios for the Swiss Alps.

Facultative vs. obligatory hemiparasitism of Pedicularis under different environmental conditions

Patrick Kuss
Cultivation of Pedicularis is notoriously difficult and usually fails without adequate hosts. However, field observation suggest that hemiparasitism is differentially expressed during distinct life-stages and under different site conditions. We test these observations experimentally with a model host grass species.

Phylogeny of the hemiparasitic plant genus Pedicularis

Patrick Kuss
The plant genus Pedicularis harbors >600 species which are predominantly distributed in polar and alpine habitats of the Northern hemisphere. Traditional intrageneric classification has largely focused on flower morphology as the main phylogenetic character whereas first molecular evidence emphasized phyllotaxy. We use chloroplast and nuclear DNA as well as quantitative and qualitative morphological traits in order to elucidate the phylogeny of this genus.
(in collaboration with Rick Ree, Field Museum Chicago)

Long-term effects of different fertilizer and land-use treatments on the composition of an alpine pasture

Christine Föhr-Heiniger, Patrick Kuss, Markus Fischer
In the early 1940’s, Werner Lüdi set up a large field experiment in the Swiss Alps to test how an unproductive alpine pasture could be improved in terms of biomass and nutritious value. He applied several fertilizer and land-use treatments and recorded species composition and frequency as well as biomass production and soil parameters. We will carry out vegetation relevés on the initial 1-m2 plots and analyze biomass and soil in order to outline long-term fertilizer and land-use impacts on biodiversity and productivity of this unique pasture.

Pollinator visitation of native and alien plants

Christine Föhr-Heiniger, Markus Fischer
One potential key factor explaining plant invasiveness is the the degree to which exotic plants are able to attract native pollinators. To test this hypothesis, we take advantage of the large number of exotic and native plant species grown under similar climatic conditions in the Botanical Garden in Bern. We carry out repeated pollinator censusus on native and exotic species to test the hyptheses that (1) exotic plants generally attract fewer pollinators than native plants, but (2) invasive exotic plants attract more pollinators than non-invasive exotic plants.
(in collaboration with Mark van Kleunen, University of Konstanz, and Mialy Mialy Harindra Razanajatovo (University of Antananarivo)