Four years of early warning and rapid eradication of common ragweed using citizen science: where are we now?

Four years of early warning and rapid eradication of common ragweed using citizen science: where are we now?Common ragweed (Ambrosia artemisiifolia L.) stands as one of the most economically burdensome invasive alien plants in Europe, owing to its allergenic pollen and agricultural impact as a weed.In Southern Belgium, where the species is in its nascent stages of invasion, the Walloon Ragweed Observatory was established in 2020 to tackle its proliferation.Utilizing citizen science as the cornerstone, surveillance efforts span Southern Belgium, facilitated through smartphone applications such as Observations.beor iNaturalist.org,as well as direct engagement with the Walloon Ragweed Observatory.A multifaceted approach, comprising training sessions, active social media engagement, specialized journal publications, video dissemination, and public media coverage, gradually mobilized stakeholders to report common ragweed sightings.From 25 known populations in 2020, reports have surged to 110, with an annual increase of approximately 30 new populations.