Category Archives: Task force Population Dynamics

Modelling the impact of ragweed management meeting

grouppictureA trio representing SMARTER WG1, 2, and the TF Population Dynamics met 1-3 August in Nijmegen, Nefigure effect of mowingtherlands, enforced by a fourth participant through skype.

They worked on the integration of experimental data on roadside mowing regimes into demographic models of ragweed across Europe to project long-term effects of such management.

Preliminary results will be presented at the final SMARTER meeting in Luxembourg.

A small excursion to a nearby park with one of the few Dutch ragweed populations revealed that there were only 10 plants left. They will likely be pulled out by some biologists working nextdoor soon…

Call for students: field work on biocontrol and population dynamics of ragweed

The Müller-Schärer Group of the University of Fribourg, Switzerland invites students to apply for a research period to participate in field research on biological control of ragweed by the accidentally introduced ragweed leaf beetle Ophraella communa, and on the population dynamics of ragweed. This includes experiments in Switzerland, Italy and France, with different collaborators from the SMARTER Task Forces Ophraella and Population Dynamics.

Applications can be submitted until 15 January 2016.

click here to enlarge flyercall Ambrosia-Ophraella 2016


WG1 meeting initiates coupled plant-insect population models (Sheffield, March 2015)

One of the aims of WG1 and the Task Force Ophraella is to assess the potential impact of candidate biocontrol agents of Ambrosia. We will do this by coupling demographic models of the biocontrol agents (insects) with those of the plant, developed by the Task Force Population Dynamics. Such a model would be of a high practical value to predict the interactions between both species and their spread over Europe.

To design the experiments needed to parameterise the models, several SMARTER members and modelling expert Yvonne Buckley met in March 2015 in Sheffield, UK, where they also presented the project in the symposium ‘Demography beyond the Population’, organized by the British Ecological Society (download the poster presentation  here).

We specifically discussed the case of the ragweed leaf beetle Ophraella communa, and its impact on Ambrosia artemisiifolia. We designed experiments that will be carried out in Northern Italy, starting in May 2015, and agreed on a STSM of Benno Augustinus (CABI, Switzerland) to Eelke Jongejans (Nijmegen, Netherlands) in April 2015.


2015/03/30 – Task Force Population Dynamics ready for a new field season after Workshop II

On 30 March 2015, the second meeting of the Task Force Population Dynamics was kindly hosted by the BOKU University (Vienna, Austria). The Task force has grown to 26 teams monitoring the demography of ragweed populations according to our standardized protocols from France to Armenia, in all important habitats of Ambrosia. Over 20 team captains were represented at the meeting, and had the premiere to wear the freshly produced SMARTER shirts.

CompleteGroupPictureAll presented their sites, and their experiences with monitoring in 2014. Three researchers presented a first analysis of the joint demographic data set from all these populations: Suzanne Lommen on the plant performance, Melinda Leitsch-Vitalos on the soil seed bank, and Caspar Hallmann on a demographical model using such data. The Task Force then agreed on some modifications of the protocol, and finally created a roadmap on how to include new participants and regions that are still missing to cover the entire European continent.

PhotoCollagePresentationsConclusion: we are ready to attack a new field season!



2014-05 Task Force Population Dynamics kicks off with workshop ragweed demography

Twenty participants, from France to Armenia, gathered Friday 23 May 2014 in Montpellier for the first meeting of the Task Force Population Dynamics. In a half-day workshop, organised by the coordinator Suzanne Lommen (CH), and the local organiser Bruno Chauvel (FR), everyone was trained to conduct the protocol, especially developed to study the demography of common ragweed.

Finding the Ambrosia plants

Finding the Ambrosia plants

The participants received the protocol, standardized record forms and help tools. After a presentation, they went outside to practice all aspects of the protocol on an artificially created population in the garden – from setting up the study plots, tagging individual plants, to measuring the viability of seeds extracted from soil samples. In the final discussion, the methods to take measures were optimized and fine-tuned. Now everyone is prepared to monitor their local ragweed populations. An online forum was initiated to share experiences during the field season.

Delimiting plots and measuring plants

Delimiting plots and measuring plants

Sampling soil, extracting and identifying Ambrosia seeds, and analysing their viability

Sampling soil, extracting and identifying Ambrosia seeds, and analysing their viability