Eight microsatellite markers isolated from common ragweed (Ambrosia artemisiifolia L.) and cross-amplification with herbarium specimens

 ; Eight microsatellite markers were developed for population genetic analyses of the common ragweed, Ambrosia artemisiifolia. Markers were tested for amplification with three populations (two recent populations from France and North America, and one historical population from herbarium specimens). These loci revealed a high level of genetic variability (5-19 alleles per locus; expected heterozygosity, 0.48-0.92). No significant deviation from Hardy-Weinberg equilibrium and no linkage disequilibrium were observed. The data thus demonstrate their utility as efficient genetic markers for determining the genetic diversity, population differentiation, and gene flow among invasive, native, and h…

Growth and reproduction responses of French invasive and North American native populations of common ragweed, Ambrosia artemisiifolia L. to defoliation

Enemy release and Evolution of Increased Competitive Ability hypotheses have been put forward to explain invasion success of introduced plant species. These hypotheses assume that the loss of natural enemies could induce an evolutionary change in plant defence and in resource allocation allowing the introduced plant populations to increase in vigour and fitness. To detect changes in functional traits following defoliation, we compared native and introduced populations of common ragweed, grown in a common garden environment. We compared six populations of Ambrosia artemisiifolia L., three from the North American native range and three from the French introduction range. We explored the effec…

How does functional diversity of plant assemblages reduce growth response of the invasive species Ambrosia artemisiifolia L. ?

Characterisation of phenotypic plasticity in seedling stage of native and invasive populations in Ambrosia artemisiifolia L.

Increased phenotypic plasticity has often been invoked as an hypothesis to explain the capacity of alien invasive plant species to colonize new environments, because it may enhance the ability of plants to cope with new biotic and abiotic conditions. Following this hypothesis, alien invasive populations should be represented by more plastic genotypes than populations in the native range. In annual species, the seedling stage is of crucial importance for population dynamics but surprisingly very few studies have investigated differences in phenotypic plasticity on seedling traits. Based on populations from the native range (North America) and the invasive range (France) of Ambrosia artemisii…

Do the high phenotypic plasticity of A. artemisiifolia L. explain its invasive success in France?

International audience; Ambrosia artemisiifolia (Asteraceae) is an invasive annual plant introduced from North America to Europe over 100 years ago. This plant species is now widespread in numerous countries all over the world, causing damages to agricultural crops and human health. Ambrosia artemisiifolia is spreading as a weed in many field crops but is also able to invade a wide range of areas such as various human disturbed habitats or riverbanks (Figure 1). A considerable variability of the life history traits of A. artemisiifolia was previously observed among and within different populations (Fumanal et al., 2007). Since the success of colonization of some invasive plant species may r…

Streams in Quebec boreal and mixed-wood forests reveal a new aquatic hyphomycete species, Dwayaangam colodena sp.nov.

International audience; Foam from eight streams in boreal and mixed-wood forests in Quebec were sampled in early and late fall 2002 to evaluate the biodiversity of their aquatic hyphomycete communities. Two regions were studied: 53-54 degrees N and 46-49 degrees N. A total of 54 species were identified. Twenty taxa were found only in the northern region, and four were unique to the southern region. A new aquatic hyphomycete, Dwayaangam colodena sp. nov., was found mostly in northern streams. It is described along with its taxonomic position.