Université de Fribourg

Neighbour origin and ploidy level drive impact of an alien invasive plant species in a competitive environment

Sun, Yan ; Müller-Schärer, Heinz ; Schaffner, Urs

In: PLOS ONE, 2016, vol. 11, no. 5, p. e0155712

Our understanding of the potential mechanisms driving the spread and naturalization of alien plant species has increased over the past decades, but specific knowledge on the factors contributing to their increased impact in the introduced range is still urgently needed. The native European plant Centaurea stoebe occurs as two cytotypes with different life histories (monocarpic diploids,...

Université de Fribourg

Origin matters: diversity affects the performance of alien invasive species but not of native species

Sun, Yan ; Müller-Schärer, Heinz ; Maron, John L. ; Schaffner, Urs

In: The American Naturalist, 2015, vol. 185, no. 6, p. 725–736

At local scales, it has often been found that invasibility decreases with increasing resident plant diversity. However, whether resident community diversity similarly resists invasion by alien versus native species is seldom studied. We examined this issue by invading constructed native plant assemblages that varied in species and functional richness with invasive alien or native Asteraceae...

Université de Fribourg

Dissecting impact of plant invaders: do invaders behave differently in the new range?

Sun, Yan ; Collins, Alexandra R. ; Schaffner, Urs ; Müller-Schärer, Heinz

In: Ecology, 2013, p. -

Knowledge from basic plant ecology suggests that impact of one plant species on another is driven by either competition for the same limiting resources, or by unique plant traits. These processes might be context specific, explaining a differential impact of exotic plant invaders in the native vs. introduced range. With the help of a conceptual framework, we aimed at identifying the relationship...

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

Plant invasions, generalist herbivores, and novel defense weapons

Schaffner, Urs ; Ridenour, Wendy M. ; Wolf, Vera C. ; Bassett, Thomas ; Müller, Caroline ; Müller-Schärer, Heinz ; Sutherland, Steve ; Lortie, Christopher J. ; Callaway, Ragan M.

In: Ecology, 2011, vol. 92, no. 4, p. 829-835

One commonly accepted mechanism for biological invasions is that species, after introduction to a new region, leave behind their natural enemies and therefore increase in distribution and abundance. However, which enemies are escaped remains unclear. Escape from specialist invertebrate herbivores has been examined in detail, but despite the profound effects of generalist herbivores in natural...