Identification leaflet on all 6 ragweed species in Europe

The SMARTER Taxonomy Group produced a brochure on the identification of 6 ragweed species in Europe for scientists, stakeholders and the general public. It contains pictures of plants, leaves, and seeds and an up-to-date overview of their biological characteristics.

Leaflet of 6 Ambrosia Species (low quality pdf)

Phenological Variation in Ambrosia artemisiifolia L. Facilitates Near Future Establishment at Northern Latitudes

Citation: Scalone, R., Lemke, A., Štefanić, E., Kolseth, A.-K., Rašić, S. and Andersson, L. (2016). Phenological Variation in Ambrosia artemisiifolia L. Facilitates Near Future Establishment at Northern Latitudes. PLoS ONE 11(11), e0166510.

PLOSONE Open Access

Abstract: The invasive weed Ambrosia artemisiifolia (common ragweed) constitutes a great threat to public health and agriculture in large areas of the globe. Climate change, characterized by higher temperatures and prolonged vegetation periods, could increase the risk of establishment in northern Europe in the future. However, as the species is a short-day plant that requires long nights to induce bloom formation, it might still fail to produce mature seeds before the onset of winter in areas at northern latitudes characterized by short summer nights. To survey the genetic variation in flowering time and study the effect of latitudinal origin on this trait, a reciprocal common garden experiment, including eleven populations of Aartemisiifolia from Europe and North America, was conducted. The experiment was conducted both outside the range limit of the species, in Sweden and within its invaded range, in Croatia. Our main hypothesis was that the photoperiodic-thermal requirements of Aartemisiifolia constitute a barrier for reproduction at northern latitudes and, thus, halts the northern range shift despite expected climate change. Results revealed the presence of a north-south gradient in flowering time at both garden sites, indicating that certain European populations are pre-adapted to photoperiodic and thermal conditions at latitudes up to, at least, 60° N. This was confirmed by phenological recordings performed in a region close to the northern range limit, the north of Germany. Thus, we conclude that there exists a high risk for establishment and spread of Aartemisiifolia in FennoScandinavia in the near future. The range shift might occur independently of climate change, but would be accelerated by it.

Co-occurrence of Artemisia and Ambrosia pollen seasons against the background of the synoptic situations in Poland

Citation: Stepalska, D., Myszkowska, D., Katarzyna, L., Katarzyna, P., Katarzyna, B., Kazimiera, C., Lukasz, G., Idalia, K., Barbara, M. W., Malgorzata, M., Malgorzata, N., Krystyna, P. W., Malgorzata, P. and Elzbieta, W. C. (2016). Co-occurrence of Artemisia and Ambrosia pollen seasons against the background of the synoptic situations in Poland. International Journal of Biometeorology.


Abstract: The Asteraceae family is one of the largest families, comprising 67 genera and 264 species in Poland. However, only a few genera, including Artemisia and Ambrosia are potential allergenic sources. The aim of the study was to estimate how often and to what degree Artemisia and Ambrosia pollen seasons co-occur intensifying human health risk, and how synoptic situations influence frequency of days with high pollen concentrations of both taxa. Artemisia and Ambrosia pollen data were collected, using the volumetric method, at 8 sites in Poland. Daily concentrations of Artemisia pollen equal to 30 grains or more and Ambrosia pollen equal to 10 grains or more were accepted as high values. Concentrations of more than 10 pollen grains were defined as high in the case of Ambrosia because its allergenicity is considered higher. High concentrations were confronted with synoptic situations. Analysis was performed on the basis of two calendars on circulation types of atmosphere in Poland (Niedźwiedź, 2006, 2015). Co-occurrence of Artemisia and Ambrosia pollen seasons is being found most often, when Ambrosia pollen season starts in the first half of August. If it happens in the last 10 days of August high pollen concentrations of Artemisia and Ambrosia do not occur at the same days. At three sites (Sosnowiec, Rzeszów, Lublin) high Ambrosia pollen concentrations during the Artemisia pollen season appear more often than in other sites under question. The high Artemisia pollen concentrations occur, when continental or polar maritime old air masses inflow into Poland. The impact of air masses on high Ambrosia pollen concentrations depends on site localizations. It is likely, that in the south-eastern part of Poland high Ambrosia pollen concentrations result from the pollen transport from east-south-south-westerly directions and the local sources. Co-occurrence of both taxa pollen seasons depends on the air masses inflow and appears more often in a south-eastern part of Poland.