First reported in the wild
Invasive species - risk of Medium Impact
Occasionally present, casual, vagrant, migratory
Introduction pathways - 1
Introduction pathways subclass - 1
NAPRA Ireland risk assessed
Annual, erect stem up to 1m tall, leaves deeply pinnately divided, only 1 greenish flower (Stace, 1997).
Primary impact is as an aeroallergen it produces allergenic pollen, which can induce allergic disease, such as rhinitis, conjunctivitis, asthma and contact dermatitis (Kazinczi et al., 2008), with heavily infested regions suffering high medical costs (e.g. €110 million per year in Hungary), (Kazinczi et al., 2008). Seasonal pollen production per plant ranges from 100 million to 3 billion in France (Fumanal et al., 2007).
Inland unvegetated or sparsely vegetated habitats; Regularly or recently cultivated agricultural, horticultural or domestic habitat
Monoecious plant, with low self compatibity though seed production ranges from 346 to 6,114 in France, depending on plant size and habitat (Fumanal, 2006). Seeds may survive for up to 39 years in the soil if conditions are suitable (Rich, 1996).
Pathway and vector description
Introduced as a contaminant in agricultural and bird seed. (Reynolds, 2002). The western and eastern European populations appear to be genetically distinct indicating separate introduction events, rather than a spread and suggests there are at least two source populations for introduction to Ireland (Gladieux et al., 2010).
Mechanism of impact
Generally found on waste ground though can be a weed of agricultural land (Reynolds, 2002).
Occasionally present, casual - Rare, localised with records from 1900 not representing a continuous presence (Reynolds,2002). Based on the climatic conditions in which it occurs in North America it cannot currently persist in the British Isles (Cunze et al., 2013), with populations generally only persisting for 2-3 years (Rich, 1996) but likely to become established in the future due to climate change (Cunze at al., 2013).
Native to the USA and Canada, introduced to Europe, Japan, Australia and Africa (Cunze et al., 2013).
Date of first record category
Records submitted to Data Centre in 2020
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How can you help
Report any sightings to the National Biodiversity Data Centre.
Delivering Alien Invasive Species In Europe (DAISIE) project listed this species as one of 100 Worst Invaders in Europe.
Reynolds, S.C.P. (2002) A catalogue of alien plants in Ireland. National Botanic Gardens. Glasnevin, Dublin. Stace, C. (1997). New Flora of the British Isles 2nd Edition. Cambridge University Press, Cambridge. Fumanal, B., Chauvel, B., & Bretagnolle, F. (2007). Estimation of pollen and seed production of common ragweed in France. Annals of Agricultural and Environmental Medicine, 14(2), 233. Cunze, S., Leiblein, M. C., & Tackenberg, O. (2013). Range expansion of Ambrosia artemisiifolia in Europe is promoted by climate change. ISRN Ecology, 2013. Gladieux, P., Giraud, T., Kiss, L., Genton, B. J., Jonot, O., & Shykoff, J. A. (2011). Distinct invasion sources of common ragweed (Ambrosia artemisiifolia) in Eastern and Western Europe. Biological invasions, 13(4), 933-944. Rich, T. C. G. (1994). Ragweeds (Ambrosia L.) in Britain. Grana, 33(1), 38-43. Kazinczi G., Béres I., Pathy Z. & Novák R. (2008). Common ragweed (Ambrosia artemisiifolia L.): A review with special regards to the results in Hungary: II. Importance and harmful effect, allergy, habitat, allelopathy and beneficial characteristics. Herbologia 9(1): 93-118.