Rothamsted Research scientists in collaboration with a EU consortium developed a model to predict the shift in distribution of ragweed in Northern latitudes in response to climate change.Common ragweed (Ambrosia artemisiifolia) is a native plant of North America that is spreading rapidly through Europe primarily through contaminated crop seed. The current identified centres of distribution are in Hungary and the Rhône valley in France. Ragweed (not to be confused with ragwort (Senecio jacobaea)) is a serious weed of some crops and also has highly allergenic pollen with late flowering that extends the hayfever season. Rothamsted Research scientists, who receive strategic funding from the BBSRC, have been part of a large interdisciplinary Fp7 European project, ATOPICA, focusing on the spread and impacts of ragweed pollen. The scientists developed a computer model to predict the shift in distribution of ragweed into more Northern latitudes in response to climate change. The results are published in the online Journal, PlosONE.Dr Jonathan Storkey, Rothamsted Research lead scientist for this study said: “The spread of ragweed is an ongoing invasion event and our results suggest that the species is yet to fill the available climatic niche space under current conditions. For example the climate in the south of the UK is predicted to be suitable for ragweed populations to persist. However, the spread and establishment of the species in new areas relies on appropriate land use, specifically the cultivation of crops such as maize and sunflower, therefore, opportunities for it to spread into new areas may currently be limited by management factors as opposed to climatic tolerances”.“Anticipating future spread in response to changes in climate or land use will, therefore, be important for mitigating potential impacts on human health and crop production”, Jonathan Storkey added.When future climate scenarios were used, the southern European limit of ragweed was predicted to remain relatively constant as it is limited by water availability. However, the increased temperatures projected for northern European regions, including countries such as the UK and Denmark, resulted in an increase in the available niche space and productivity of the species in more Northern latitudes.Dr Semenov, Rothamsted Research said: “Whether or not ragweed will have serious impacts in the future in the UK will be determined by cropping patterns and the level of control; however, on the basis of our results ongoing surveillance and research on existing ragweed patches in the UK is recommended”.