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Université de Fribourg

Aboveground environment type, soil nutrient content and arbuscular mycorrhizal fungi explain establishment success of Centaurea jacea on ex-arable land and in late-successional grasslands

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

In: Plant and Soil, 2009, vol. 322, no. 1-2, p. 115-123

We studied the relative importance of the aboveground and belowground environment for survival and growth of emerged seedlings of Centaurea jacea to better understand the general difficulty of establishing late-successional species at restoration sites on ex-arable land. Potted seedlings growing on soil from six late-successional grasslands and from six ex-arable (restoration) sites were...

Université de Fribourg

Allopolyploid origin of highly invasive Centaurea stoebe s.l. (Asteraceae)

Mráz, Patrik ; Garcia-Jacas, Núria ; Gex-Fabry, Emilie ; Susanna, Alfonso ; Barres, Laia ; Müller-Schärer, Heinz

In: Molecular Phylogenetics and Evolution, 2012, vol. 62, no. 2, p. 612–623

Spotted knapweed (Centaurea stoebe) occurs from Western Asia to Western Europe both as diploid and tetraploid cytotypes, predominantly in single-cytotype populations with higher frequency of diploid populations. Interestingly, only tetraploids have been recorded so far from its introduced range in North America where they became highly invasive. We performed phylogenetic and network analyses of...

Université de Fribourg

Anthropogenic disturbance as a driver of microspatial and microhabitat segregation of cytotypes of Centaurea stoebe and cytotype interactions in secondary contact zones

Mráz, Patrik ; Španiel, Stanislav ; Keller, Andreas ; Bowmann, Gillianne ; Farkas, Alexandre ; Šingliarová, Barbora ; Rohr, Rudolf P. ; Broennimann, Olivier ; Müller-Schärer, Heinz

In: Annals of Botany, 2012, p. -

Background and Aims: In a mixed-ploidy population, strong frequency-dependent mating will lead to the elimination of the less common cytotype, unless prezygotic barriers enhance assortative mating. However, such barriers favouring cytotype coexistence have only rarely been explored. Here, an assessment is made of the mechanisms involved in formation of mixed-ploidy populations and coexistence...

Université de Fribourg

Areas of high conservation value in Georgia: present and future threats by invasive alien plants

Thalmann, Daniela Julia Klara ; Kikodze, David ; Khutsishvili, Manana ; Kharazishvili, David ; Guisan, Antoine ; Broennimann, Olivier ; Müller-Schärer, Heinz

In: Biological Invasions, 2015, vol. 17, no. 4, p. 1041–1054

Georgia is known for its extraordinary rich biodiversity of plants, which may now be threatened due to the spread of invasive alien plants (IAP). We aimed to identify (1) the most prominent IAP out of 9 selected potentially invasive and harmful IAP by predicting their distribution under current and future climate conditions in Georgia as well as in its 43 Protected Areas, as a proxy for areas of...

Université de Fribourg

Assessing the risks of non-target feeding by the accidentally introduced ragweed leaf beetle, Ophraella communa, to native European plant species

Augustinus, Benno Andreas ; Gentili, Rodolfo ; Horvath, David ; Naderi, Ruhollah ; Sun, Yan ; Tournet, Anne-Marth Truce Eleonoor ; Schaffner, Urs ; Müller-Schärer, Heinz

In: Biological Control, 2020, vol. 150, p. 104356

In 2013, the North American oligophagous leaf beetle, Ophraella communa LeSage (Coleoptera: Chrysomelidae), was found in Europe for the first time. Recent studies in Northern Italy and Southern Switzerland record extensive defoliation by O. communa on its preferred host, common ragweed, Ambrosia artemisiifolia L. (Asteraceae, Tribe Heliantheae), and reductions in its flowering and seeding. In...

Université de Fribourg

Biogeographic effects on early establishment of an invasive alien plant

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

In: American Journal of Botany, 2015, vol. 102, no. 4, p. 621–625

Premise of the study: Biotic resistance is often studied in the context of how interactions between native biota and invading species influence the success of those invaders. Seldom, however, is the strength of “resistance” compared biogeographically, where the ability of a species to impede invader establishment is contrasted between an invader’s native and introduced recipient...

Université de Fribourg

Biological control opportunities of ragweed are predicted to decrease with climate change in East Asia

Sun, Yan ; Zhou, Zhongshi ; Wang, Rui ; Müller-Schärer, Heinz

In: Biodiversity Science, 2017, vol. 25, no. 12, p. 1285-1294

The control of invasive alien plants (IAP) that jeopardize our ecosystems and economy constitutes a significant challenge for natural resource management. Classical biological control referring to the introduction of specialist antagonists from the native range has proven to be a highly cost-effective management tool against IAP. A critical issue in biological control research is to guide...