About

The change in grassland use has led to a major change in the vegetation structure in recent years. In some stands, this has led to a dominance of undesirable species. One of these problem species is water ragwort (Senecio aquaticus). While the species used to be widespread in the wet grasslands of Central Europe, but usually only reached low cover values, strong local increases and the formation of dominant stands have been observed in Austria, southern Bavaria, Upper Swabia and Switzerland in recent years. This is critical both for agricultural use and for the environment, as ragwort contains toxic pyrrolizidine alkaloids in all parts of the plant, which can lead to severe liver damage. Previous studies (e.g. Suter & Lüscher 2008, 2012; Gehring & Thyssen 2016) have shown that cutting and the use of herbicides are the most effective methods of control. The findings on measures to regulate water ragwort on extensively used areas relevant to nature conservation, where the aforementioned approaches are often not economically viable or are not permitted due to environmental regulations, have so far only been examined to a limited extent (Bassler et al. 2016).The aim of this project is therefore to develop management concepts in which a reduction in water ragwort populations is achieved primarily through competition with the plant population and an adapted cutting regime.

One of the approaches to reduction pursued in this project is based on so-called darkening, in which infrequent or late mowing creates a high and competitive plant population that leads to the suppression of the light-requiring water ragwort. The basis for this is the promotion of shading and the optimization of the cutting regime to reduce the biomass and seed production of water ragwort. This approach is being pursued at six sites with comparatively low productivity in the Bavarian and Württemberg Allgäu. At seven other, somewhat more productive trial sites, a second approach is being pursued in which, in addition to thinning, a cutting regime is also being tested that is intended to minimize the reproduction of water ragwort by cutting at flowering. Recommendations for environmentally friendly control measures are to be derived from the trials. Another important aim of the investigations is to ensure that the recommended methods have as little negative impact as possible on the biodiversity of the wet grassland. The investigations will be accompanied by exact tests on light requirements, competitive ability and cutting tolerance under controlled greenhouse conditions.

Partner

Allgäu Mire Alliance

Ravensburg Landscape Conservation Association (LEV)

Baden-Württemberg Agricultural Center (LAZBW)

City of Kempten

International Publications

Krieger MT, Teixeira LH, Grant K, Kollmann J, Albrecht H (2023) Reconciling the control of the native invasive Jacobaea aquatica and ecosystem multifunctionality in wet grasslands. – Basic and Applied Ecology 68, 13–22. https://doi.org/10.1016/j.baae.2023.02.001

Krieger MT, Ditton J, Albrecht H, Baaij BM, Kollmann J, Teixeira LH (2022) Controlling the abundance of a native invasive plant does not affect species richness or functional diversity of wet grasslands. – Applied Vegetation Science 25, e12676. https://doi.org/10.1111/avsc.12676

Krieger MT, Ditton J, Albrecht H, Linderl L, Kollmann J, Teixeira LH (2022) Effects of shading and site conditions on vegetative and generative growth of a native grassland invader. – Ecological Engineering 178, 106592. https://doi.org/10.1016/j.ecoleng.2022.106592

German Publications

Gehring K, Kuhn G, Albrecht H, Ditton J (2022) Wasser-Greiskraut richtig managen. topagrar.

Albrecht H, Ditton J, Kuhn G, Kollmann J, Krieger MT, Mayer F, Teixeira LH, Gehring K (2022) Management von Wasser-Greiskraut (Jacobaea aquatica) in Wirtschaftsgrünland des ökologischen Landbaus. – Julius-Kühn-Archiv, 468, 117–121. https://doi.org/10.5073/20220117-134458

Kuhn G, Mayer F, Wagner T, Krieger MT, Laumer M, Ditton J, Albrecht H, Kollmann J, Gehring K (2022) Zusammenhang zwischen dem Auftreten von Wasser-Greiskraut (Jacobaea aquatica) und landschaftlichen sowie landwirtschaftlichen Faktoren in Bayern. – Julius-Kühn-Archiv 468, 122–127. https://doi.org/10.5073/20220117-134915

Albrecht H, Kollmann J, Kuhn G, Ditton J, Teixeira L, Linderl L, Laumer M, Mayer F, Wagner T, Gottschalk C, Gehring K (2021) Effektives Management von Wasser-Kreuzkraut in bayerischem Grünland. – Schriftenreihe der Bayerischen Landesanstalt für Landwirtschaft.

Krieger, MT, Kollmann J, Albrecht H (2020) Regulierung von Wasser-Greiskraut in naturschutzfachlich wertvollem Grünland. –LUBW Naturschutz-Info 1-2, 73–75.

Krieger MT, Albrecht H (2019) „Ausdunkelung“ – eine Möglichkeit, das Wasserkreuzkraut (Senecio aquaticus) zu reduzieren? – ANLiegen Natur 41/1, 172–174.