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Université de Fribourg

Scale-dependent effects of land use on plant species richness of mountain grassland in the European Alps

Spiegelberger, Thomas ; Matthies, Diethart ; Müller-Schärer, Heinz ; Schaffner, Urs

In: Ecography, 2006, vol. Volume 29, p. 541-548

Traditionally managed mountain grasslands in the Alps are species-rich ecosystems that developed during centuries of livestock grazing. However, changes in land use including fertilisation of well accessible pastures and gradual abandonment of remote sites are increasingly threatening this diversity. In five regions of the Swiss and French Alps we assessed the relationship between land use, soil...

Université de Fribourg

Detecting local adaptation in widespread grassland species – the importance of scale and local plant community

Bischoff, Armin ; Crémieux, Lisèle ; Smilauerova, Marie ; Lawson, Clare S. ; Mortimer, Simon R. ; Dolezal, Jiri ; Lanta, Vojtech ; Edwards, Andrew R. ; Brook, Alex J. ; Macel, Mirka ; Leps, Jan ; Steinger, Thomas ; Müller-Schärer, Heinz

In: Journal of Ecology, 2006, vol. 94, p. 1130-1142

1 Adaptation of plant populations to local environments has been shown in many species but local adaptation is not always apparent and spatial scales of differentiation are not well known. In a reciprocal transplant experiment we tested whether: (i) three widespread grassland species are locally adapted at a European scale; (ii) detection of local adaptation depends on competition with the...

Université de Fribourg

Safe sites for tree regeneration in wooded pastures: A case of associational resistance ?

Smit, Christian ; Béguin, Daniel ; Buttler, Alexandre ; Müller-Schärer, Heinz

In: Journal of Vegetation Science, 2005, vol. 16, no. 2, p. 209-214

Question: Are tree saplings in wooded pastures spatially associated with specific nurse structures or plants that facili-tate tree sapling survival? Location: Wooded pastures in the Jura Mountains, Switzer-land. Methods: In two sites, 73 km apart, we sampled 294 plots of4 m², systematically distributed on 1 ha. We recorded number and height of all established Picea abies...

Université de Fribourg

Soil carbon addition affects plant growth in a species-specific way

Eschen, René ; Müller-Schärer, Heinz ; Schaffner, Urs

In: Journal of Applied Ecology, 2006, vol. 43, no. 1, p. 35-42

1. Restoration of ex-arable land to species-rich habitats has become common practice in Europe as a result of Agri-Environment Regulations. The results, however, are highly variable and often disappointing. Competition from weedy species as a result of high soil inorganic nitrogen levels can negatively affect the establishment and growth of desirable grassland plant species. One method...

Université de Fribourg

The Relation Between Unpalatable Species, Nutrients and Plant Species Richness in Swiss Montane Pastures

Kleijn, David ; Müller-Schärer, Heinz

In: Biodiversity and Conservation, 2006, vol. 15, no. 12, p. 3971-3982

In agriculturally marginal areas, the control of unpalatable weeds on species rich pastures may become problematic due to agricultural and socio-economic developments. It is unclear how increased dominance of unpalatable species would affect the botanical diversity of these grasslands. We investigated whether there was any relationship between plant species diversity and the abundance of...

Université de Fribourg

Modeling the impact of a biocontrol agent, Puccinia lagenophorae, on interactions between a crop, Daucus carota, and a weed, Senecio vulgaris

Frantzen, J. ; Müller-Schärer, Heinz

In: Biological Control, 2006, vol. 37, no. 3, p. 301-306

The impact of a biocontrol agent spreading from a point source on crop–weed interactions was modeled. The model encompassed: (i) severity of crop–weed competition as affected by a rust pathogen, (ii) velocity of spread of the rust pathogen, and (iii) density of infected plants introduced in the weed population as starting points (inoculum sources) for an epidemic. The model was parameterized...

Université de Fribourg

Seed provenance matters — Effects on germination of four plant species used for ecological restoration

Bischoff, Armin ; Vonlanthen, Beatrice ; Steinger, Thomas ; Müller-Schärer, Heinz

In: Basic and Applied Ecology, 2006, vol. 7, no. 4, p. 347-359

The use of local seed provenances is often recommended in restoration and habitat creation because they are thought to be better adapted to local habitat conditions. However, spatial scales and the degree of population differentiation are not well known and germination is often not included in comparisons between provenances. We analysed germination as a key trait of plant development in five...

Université de Fribourg

Unpalatable plants facilitate tree sapling survival in wooded pastures

Smit, Christian ; Den Ouden, Jan ; Müller-Schärer, Heinz

In: Journal of Applied Ecology, 2006, vol. 43(2), p. 305

1. In endangered wooded pasture ecosystems established tree saplings are frequently found in spatial association with protective structures, suggesting nurse effects. This associational resistance is thought to be a driving force behind tree regeneration in wooded pastures. Experimental evidence for associational resistance is, however, scarce. We studied the effects of unpalatable plants on tree...

Université de Fribourg

Evolution in invasive plants: implications for biological control

Müller-Schärer, Heinz ; Schaffner, Urs ; Steinger, Thomas

In: Trends in Ecology and Evolution, 2004, vol. 19, p. 417-422

Evidence is increasing that invasive plants can undergo rapid adaptive evolution during the process of range expansion. Here, we argue that evolutionary change during invasions will also affect plant–antagonist inter-actions and, thus, will have important implications for biological control programmes targeted at invasive plants. We explore how altered selection in the new range might influence...