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Video: Common Ragweed – Seeds, Pollen and Allergy

The French Observatory of ragweeds has produced a 14-minutes-video on the issue of Ambrosia artemisiifolia for the general public, filmed during the summer of 2014  in France. Although made in France, this is a great movie showing many aspects of the ragweed problem, from biology to policy, including impressive images of endless ragweed fields!

We highly recommend it to everyone interested in ragweed.

The films are now on Youtube in French  and with English subtitles

Inducing competition: intensive grassland seeding to control Ambrosia artemisiifolia

Citation: Gentili, R., Gilardelli, F., Ciappetta, S., Ghiani A. and Citterio, S. (2015) Inducing competition: intensive grassland seeding to control Ambrosia artemisiifolia L. Weed Research DOI: 10.1111/wre.12143

Wiley Online Library

Abstract: The invasion of Ambrosia artemisiifolia across European countries has been favoured by its ecological amplitude and by its ability to colonise and dominate disturbed/ruderal areas that have lost competition from native species. We supposed that a strong competition for habitat resources may inhibit A. artemisiifolia growth, generating a negative feedback to its establishment. Based on this hypothesis, in this study, we undertook a 1-year field experiment to assess the effect of mixtures of grassland species on A. artemisiifolia growth and fitness in bare soils. We applied three different treatments within an abandoned quarry area invaded by A. artemisiifolia: (i) spontaneous succession, (ii) hayseed and (iii) a commercial seed mixture. Within plots, we recorded vegetation parameters, A. artemisiifolia abundance and traits. Results obtained after one growing season showed that the commercial seed resulted in the strongest reduction of A. artemisiifolia growth rate in terms of plant height, lateral spread and leaf size. This was ascribed to higher density of plants that play a key role in reducing biomass and fitness of A. artemisiifolia. However, hayseed should be preferred, as it preserves local biodiversity. Seeding mixtures of grassland species can successfully suppress A. artemisiifolia in the first year of establishment on a vegetation-free soil derived from quarry activities. This study indicated that inducing dominance of different native species in a newly developing plant community should enhance competition for resources, reducing the success of early coloniser non-native species.

Space matters when defining effective management for invasive plants

Citation: Meier, E. S., Dullinger, S., Zimmermann, N. E., Baumgartner, D. Gattringer, A. and Hülber, K. (2014) Space matters when defining effective management for invasive plants. Diversity and Distributions, 20(9); 1029–1043

Wiey Online Library

Abstract: Aim – Invasive alien species are a threat to biodiversity and can harm resident plants, animals, humans and infrastructure. To reduce deleterious effects, effective management planning for invasive plants is required. Currently, the effectiveness of management is primarily optimized locally through eradication of individual populations. By contrast, spatial prioritization of control activities at the landscape level has received less attention, despite its potential to improve management planning in complex landscapes, especially under budget constraints. Location – North-eastern Switzerland, Europe. Methods – We used a dynamic simulation model to evaluate the effectiveness of spatially designed management planning for controlling the expansion of three invasive alien plants (IAPs; Heracleum mantegazzianum, Impatiens glandulifera and Reynoutria japonica) across a heterogeneous landscape in North-eastern Switzerland. The model predicted the spread of IAPs from their current distribution under constraints of 361 control options differing in local intensity, frequency, duration, area and spatial prioritization of eradication measures. Results – Our results demonstrate that IAP-control actions under a restricted budget are more effective if control actions are spatially prioritized. Most effective spatial treatments generally prioritized small populations in the case of the annual species and large populations in the case of the perennial species. Further, applying intensive control at early stages generally increased effectiveness of control. Main conclusions – For IAP-management planning, our findings suggest that control should be applied early when IAPs start spreading, to maximize success or minimize costs. Further, spatial prioritization schemes are particularly useful under limited financial means for IAP-management. Finally, our modelling approach may serve as a proof of concept to evaluate the effectiveness of control actions of various IAPs in complex landscapes.