AgriWeedClim
Oct 16
PresentationEmerging Agricultural Weeds under climate and land-use changes in Central Europe: identifying high-risk species, modelling their distributions, assessing impacts and management need.
On October 16, 2024, the final meeting of the AgriWeedClim project took place at AGES in Vienna. Researchers from the University of Vienna, Masaryk University in Brno, and the Austrian Agency for Health and Food Safety (AGES) came together to present and discuss results from three years of collaboration.
The day began with an overview of the project by Franz Essl, followed by Michael Glaser, who summarized the major changes in Central European weed flora over the past decades. Swen Follak (AGES) then introduced new and emerging weeds in Austria, highlighting practical challenges for agriculture.
After the coffee break, Georg Martin Hörmann presented risk maps for current and future weed spread, showing how climate scenarios may influence their distributions. Swen Follak (AGES) followed with a presentation of a new management tool, designed to help practitioners respond to these challenges. The morning concluded with a discussion on current problems in weed control.
In the afternoon, I presented my research on the increase of neophytes at regional and local scales in Central European arable fields, based on 21,747 vegetation plots from the AgriWeedClim database. This work focused on long-term changes between 1930 and 2019 and addressed two scales:
Regional level: We analyzed how the proportion of plots containing at least one neophyte changed over time. The results showed a doubling of neophyte presence across Central Europe. This increase was mainly driven by a few widespread species, especially Veronica persica, which contributed the most to the observed trend. While species richness promoted neophyte occurrence, latitude had a negative effect, indicating slower spread in northern regions, whereas longitude showed a positive effect, pointing to stronger expansion in the east.
Local level: At the within-plot scale, both the proportion and relative cover of neophytes doubled over time. In contrast, archaeophytes remained largely stable in both occurrence and abundance. The local spread was not only determined by common species but also by less frequent, yet locally dominant neophytes such as Galinsoga quadriradiata and Amaranthus retroflexus. Climatic and geographic factors also played a role: warmer temperatures increased the likelihood of neophyte presence, whereas both latitude and longitude had negative effects on their local abundance.
Together, these results underline a clear and consistent trend: Neophytes have become increasingly dominant in Central European arable fields over the last century, while archaeophytes have shown little change. Importantly, the dynamics differ between scales. Regional spread is driven mainly by widespread species, whereas local dominance can also emerge from less common but aggressive weeds.
This research became the basis of my first publication and now forms the first chapter of my PhD thesis, providing a detailed picture of how alien species are reshaping agricultural weed communities.
The session continued with Swen Follak and Elisabeth Reiter (AGES), who reported on results from the StopDatura project. Their focus was the rapid spread and risks posed by Datura stramonium (Jimsonweed), a toxic invasive species threatening harvests in Austria. The meeting closed with a final discussion, where participants reflected on the implications of the project findings for weed management, policy, and future research directions.