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Evidence for a combination of pre-adapted traits and rapid adaptive change in the invasive plant Centaurea stoebe

  • Henery, Martin L. Department of Biology, Unit of Ecology and Evolution, University of Fribourg, Switzerland
  • Bowman, Gillianne Department of Biology, Unit of Ecology and Evolution, University of Fribourg, Switzerland
  • Mráz, Patrik Department of Biology, Unit of Ecology and Evolution, University of Fribourg, Switzerland
  • Treier, Urs A. Department of Biology, Unit of Ecology and Evolution, University of Fribourg, Switzerland - Department of Biological Sciences, Ecoinformatics & Biodiversity, Aarhus University, Denmark
  • Gex-Fabry, Emilie Department of Biology, Unit of Ecology and Evolution, University of Fribourg, Switzerland
  • Schaffner, Urs CABI Europe – Switzerland, Delémont, Switzerland
  • Müller-Schärer, Heinz Department of Biology, Unit of Ecology and Evolution, University of Fribourg, Switzerland
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    11.06.2010
Published in:
  • Joural of Ecology. - 2010, vol. 98, no. 4, p. 800–813
biological invasion
Centaurea stoebe
plant life cycle
plant traits
ploidy
rapid adaptive change
reproductive potential
English 1. Introduced plants have the potential to rapidly evolve traits of ecological importance that may add to their innate potential to become invasive. During invasions, selection may favour genotypes that are already pre-adapted to conditions in the new habitat and, over time, alter the characteristics of subsequent generations. 2. Spotted knapweed (Centaurea stoebe) occurs in two predominantly spatially separated cytotypes in its native range (Europe–Western Asia), but currently only the tetraploid form has been confirmed in the introduced range (North America), where it is invasive. We used several common garden experiments to examine, across multiple populations, whether tetraploids and diploids from the native range differ in life cycle, leaf traits and reproductive capacity and if such differences would explain the predominance of tetraploids and their advance into new habitats in the introduced range. We also compared the same traits in tetraploids from the native and introduced range to determine whether any rapid adaptive changes had occurred since introduction that may have enhanced invasive potential of the species in North America. 3. We found tetraploids had lower specific leaf area, less lamina dissection and fewer, narrower leaves than diploids. Diploids exhibited a monocarpic life cycle and produced few if any accessory rosettes. Diploids produced significantly more seeds per capitulum and had more capitula per plant than tetraploids. In contrast, the vast majority of European tetraploids continued to flower in both seasons by regenerating from multiple secondary rosettes, demonstrating a predominantly polycarpic life cycle. 4. During early growth tetraploids from North America achieved greater biomass than both tetraploids and diploids from the native range but this did not manifest as larger above-ground biomass at maturity. In North American tetraploids there was also evidence of a shift towards a more strictly polycarpic life cycle, less leaf dissection, greater carbon investment per leaf, and greater seed production per capitulum. 5.Synthesis: our results suggest that the characteristics of tetraploid C. stoebe pre-adapted them (compared to diploid conspecifics) for spread and persistence of the species into habitats in North America characterized by a more continental climate. After the species’ introduction, small but potentially important shifts in tetraploid biology have occurred that may have contributed significantly to successful invasion.
Faculty
Faculté des sciences et de médecine
Department
Département de Biologie
Language
  • English
Classification
Biological sciences
License
License undefined
Identifiers
Persistent URL
https://folia.unifr.ch/unifr/documents/301649
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