Université de Fribourg

Cytotype differences modulate eco-geographical differentiation in the widespread plant Centaurea stoebe

Hahn, Min A. ; Müller-Schärer, Heinz

In: Ecology, 2013, vol. 94, no. 5, p. 1005–1014

The evolution of optimal life history strategies is central for the fitness of organisms in a given environment. Besides divergent selection, other factors may determine regional patterns of differentiation and contribute to life history evolution. In a common-garden environment over three years, we examined life history differentiation across different eco-geographical regions and effects of a...

Université de Fribourg

Prospects for biological control of Ambrosia artemisiifolia in Europe: learning from the past

Gerber, E. ; Schaffner, Urs ; Gassmann, A. ; Hinz, H. L. ; Seier, M. ; Müller-Schärer, Heinz

In: Weed Research, 2011, vol. 51, no. 6, p. 559–573

The recent invasion by Ambrosia artemisiifolia (common ragweed) has, like no other plant, raised the awareness of invasive plants in Europe. The main concerns regarding this plant are that it produces a large amount of highly allergenic pollen that causes high rates of sensitisation among humans, but also A. artemisiifolia is increasingly becoming a major weed in agriculture. Recently, chemical...

Université de Fribourg

Nurse plants, tree saplings and grazing pressure: changes in facilitation along a biotic environmental gradient

Smit, Christian ; Vandenberghe, Charlotte ; Ouden, Jan den ; Müller-Schärer, Heinz

In: Oecologia, 2007, vol. 152, no. 2, p. 265-273

Current conceptual models predict that an increase in stress shifts interactions between plants from competitive to facilitative; hence, facilitation is expected to gain in ecological importance with increasing stress. Little is known about how facilitative interactions between plants change with increasing biotic stress, such as that incurred by consumer pressure or herbivory (i.e....