Citation: Gallien, L., Thuiller, W., Fort, N., Boleda, M., Alberto, F. J., Rioux, D., Laine, J. and Lavergne, S. (2016). Is There Any Evidence for Rapid, Genetically-Based, Climatic Niche Expansion in the Invasive Common Ragweed? PLoS ONE 11(4), e0152867.
Abstract: Climatic niche shifts have been documented in a number of invasive species by comparing the native and adventive climatic ranges in which they occur. However, these shifts likely represent changes in the realized climatic niches of invasive species, and may not necessarily be driven by genetic changes in climatic affinities. Until now the role of rapid niche evolution in the spread of invasive species remains a challenging issue with conflicting results. Here, we document a likely genetically-based climatic niche expansion of an annual plant invader, the common ragweed (Ambrosia artemisiifolia L.), a highly allergenic invasive species causing substantial public health issues. To do so, we looked for recent evolutionary change at the upward migration front of its adventive range in the French Alps. Based on species climatic niche models estimated at both global and regional scales we stratified our sampling design to adequately capture the species niche, and localized populations suspected of niche expansion. Using a combination of species niche modeling, landscape genetics models and common garden measurements, we then related the species genetic structure and its phenotypic architecture across the climatic niche. Our results strongly suggest that the common ragweed is rapidly adapting to local climatic conditions at its invasion front and that it currently expands its niche toward colder and formerly unsuitable climates in the French Alps (i.e. in sites where niche models would not predict its occurrence). Such results, showing that species climatic niches can evolve on very short time scales, have important implications for predictive models of biological invasions that do not account for evolutionary processes.
The first observations of active Ophraella adults, eggs, and larvae have been made in April 2016 in Northern Italy and Southern Switzerland. We would like to encourage anybody who works on the ragweed leaf beetle to participate in ourOphraella occurrence survey: http://ragweed.eu/ophraella-survey/ ‘
Citation: Kassai-Jáger E, Seier MK, Evans HC, Kiss L. 2015. Molecular identification and pathogenicity assessment of a rust fungus infecting common ragweed (Ambrosia artemisiifolia) in its native North American range. European Journal of Plant Pathology 145:81-87.
Abstract: A rust fungus collected from common ragweed (Ambrosia artemisiifolia) in Texas, USA, was identified as belonging to the Puccinia xanthii morphospecies based on its nrDNA ITS sequence. Pathogenicity studies carried out with this rust accession under quarantine conditions in the UK showed that the fungus was highly virulent on A. artemisiifolia plants from Australia. Recently, P. xanthii has been proposed as a potential classical biological control agent (CBCA) for common ragweed in its invasive range, focusing on Europe, despite previous doubts about its biocontrol potential. The results of the pathogenicity tests reported here support the suitability of this pathogen as a CBCA for common ragweed.
Announcing two vacancies in the lab of Prof. Heinz Müller-Schärer at the University of Fribourg, Switzerland.
The projects capitalize on ongoing studies in the framework of the COST Action SMARTER, on the invasive common ragweed and the interaction with one candiate biocontrol agent.
Fourteen members of WG1 and the Ophraella Task Force met on 23/03/2016. The meeting was organized by Prof. Francesco Vidotto from the University of Turin.
In the meeting, collaboration for the upcoming field season and the output for the Action that will last until November 2016 was discussed. During the lunch excursion, the first young seedlings of Ambrosia artemisiifolia were found, as well as an overwintering Ophraella communa as a motivating indicator for the start of the next field season.
WG1 and the Ophraella Task Force at Torino