Effects of climate change and seed dispersal on airborne ragweed pollen loads in Europe

Abstract

Common ragweed (Ambrosia artemisiifolia) is an invasive alien species in Europe producing pollen that causes severe allergic disease in susceptible individuals 1 . Ragweed plants could further invade European land with climate and land-use changes 2,3 . However, airborne pollen evolution depends not only on plant invasion, but also on pollen production, release and atmospheric dispersion changes. To predict the e ect of climate and land-use changes on airborne pollen concentrations, we used two comprehensive modelling frameworks accounting for all these factors under high-end and moderate climate and land-use change scenarios. We estimate that by 2050 airborne ragweed pollen concentrations will be about 4 times higher than they are now, with a range of uncertainty from 2 to 12 largely depending on the seed dispersal rate assumptions. About a third of the airborne pollen increase is due to on-going seed dispersal, irrespective of climate change. The remaining two-thirds are related to climate and land-use changes that will extend ragweed habitat suitability in northern and eastern Europe and increase pollen production in established ragweed areas owing to increasing CO 2 . Therefore, climate change and ragweed seed dispersal in current and future suitable areas will increase airborne pollen concentrations, which may consequently heighten the incidence and prevalence of ragweed allergy.Common ragweed is native in North America. Since the end of the nineteenth century it has invaded large regions in Europe 4,5 and also parts of Australia, South America and East Asia 6 . The sensitization of the human population to ragweed pollen is increasing in many countries 7 . In Europe, its established presence is at present largely limited to several areas in the [42 • N-47 • N] latitudinal band (Pannonian plain, northern Italy and southeastern France) and in areas with disturbed land, such as agricultural areas or along roads and railways. However, there is a high potential for further spread given that suitable, although not yet invaded, habitats are substantial 8,9 . Plant density may also further increase in established infested areas. Factors determining the rate of spread of ragweed plants within its current climatic niche include seed dispersal due to natural or anthropogenic processes (for example, spread through contaminated crop seeds), land-use change (which would provide changes in disturbed land areas) and the efficiency of ragweed eradication policies. Climate change may further impact the spread of ragweed by altering the climatic niche determined by physiological thresholds or affecting cropping patterns 5,10,11 . Ragweed airborne pollen concentrations depend not only on plant infestation, but also on phenology, pollen production, release, dispersion and atmospheric transport. Recent modelling efforts 12-15 have led to increasingly successful simulations of airborne pollen concentrations. Although previous work was mostly devoted to short-term forecasts to inform sensitized populations, the maturity of the mode...

The Contradiction Between Taxa of Conservation Significance and Invasive Species – A Case Study of Sustainable Development in Mala Planina

“…Six of these 24 invasive species (Acer negundo, Ailanthus altissima, Ambrosia artemisiifolia, Amorpha fruticosa, Bidens frondosus, Robinia pseudoacacia) are included in the "top 10" list of the most problematic invasive species in Bulgaria (Petrova et al, 2013). Hamaoui-Laguel et al (2015) recently revealed concerning information -by 2050 airborne ragweed pollen (Ambrosia artemisiifolia) concentrations will be about 4 times higher than they are now and Mala Planina isn't an isolated place in the environment. Another problem is that the list of invasive alien species targeted for action under the January 2015 EU legislation includes just 37 entries (http://ec.europa.eu/environment/nature/invasivealien/index_en.htm), while the 24 invasive plant species are described only in a small mountainous area in Bulgaria.…”

Ragweed pollen production and dispersion modelling within a regional climate system, calibration and application over Europe

“…The modelling framework presented here allows simultaneous estimation of ragweed pollen risk both for hindcast simulations (including sensitivity studies to different parameters) and for study of potential risk evolution changes under future climate scenarios as illustrated in Hamaoui-Laguel et al (2015). Still a long list of uncertainties hinders an accurate estimate of the airborne pollen patterns and risk within the presented framework.…”

“…This inventory is further calibrated against airborne pollen observations to reproduce the ragweed distribution with high accuracy, according to Prank et al (2013). Recently Hamaoui-Laguel et al (2015) used the observations collected in Bullock et al (2012), combined with simplified assumptions on plant density and a calibration using observations to obtain a ragweed density inventory map. This approach made use of the Organising Carbon and Hydrology in Dynamic Ecosystems (ORCHIDEE) and the Phenological Modeling Platform (PMP) for obtaining daily available pollens (potential emissions) in Europe.…”

“…In this context the present study introduces a modelling framework designed to simulate production and dispersion of ragweed pollen. Ultimately these models can be used for investigating the effects of changing climate and land use on ragweed (Hamaoui-Laguel et al, 2015) and for providing relevant data to health impact investigators.…”

“…Ragweed spatial distribution is obtained through a procedure discussed in Hamaoui-Laguel et al (2015). For country where observations are available and of sufficient quality, ragweed distribution is assumed to result from habitat suitability combined with infestation (not all suitable habitats are populated).…”