Magdalena Szymura¹, Sebastian Świerszcz², Tomasz H. Szymura³ and Dawid Jarczak¹

¹Institute of Agroecology and Plant Production, Wrocław University of Environmental and Life Sciences, Wrocław, Poland
²Botanical Garden-Centre for Biological Diversity Conservation, Polish Academy of Sciences, Warsaw, Poland
³Department of Ecology, Biogeochemistry and Environmental Protection, University of Wrocław, Wrocław, Poland

e-mail: magdalena.szymura@upwr.edu.pl

The semi-natural grasslands are species-rich and form habitats for numerous rare and endangered species. The grasslands also provide a wide range of ecosystem services: provisioning, regulating (e.g. climate regulation, erosion prevention and regulation of water flows), habitat, cultural and amenity. In Europe, in the last hundred years, more than 90% of semi-natural grasslands were destroyed due to production intensification or abandonment. To prevent this deterioration, semi-natural grasslands are recently protected in the pan-European Nature 2000 network. Despite the current protection, the effect of agriculture abandoning is still visible in Europe.

The spread of exotic species is a crucial element of environmental global changes. Invasion by alien plant species alters biodiversity, landscape structure, ecosystem functions and services, local economy, as well as human health and well-being. One of the most common invasive plants in abandoned lands and grasslands in Europe are species from Solidago genus of the North American origin, especially S. gigantea Aiton and S. canadensis L. s.l. Consequently, it is necessary to restore areas occupied by the goldenrods. The long-term successful elimination of the invasive species needs two stages: removing of invasive plant species and the subsequent habitat restoration (Reid et al. 2009).

We show the result of a long-term field experiment where species-rich grasslands were restored on post-agricultural lands overgrown by dense stands of Solidago spp. We examined different methods of Solidago spp. eradication and grassland species seed supply. We would like to answer the question: which method of eradication is the best, in the long run? As the treatments were applied: sod-cutting (depth ~1 cm); rototilling; and herbicide application (glyphosate, 5 L ha-1). Afterwards, two methods of seed application were used: (i) spreading fresh hay, obtained from a high-biodiversity meadow, and (ii) sowing the commercial seed mixture. These treatments and seed application were used once, in the first year of the experiment. All plots were mowed twice per year during the course of the experiment. Our targets in the experiment were: the highest possible reduction of Solidago biomass/cover and simultaneously increase of graminoids and grassland herbs cover/biomass. After five years we substantially reduced the cover of Solidago (average form 95% to 25%). We found significant differences between the effects of seed addition and lack of differences between applied methods of eradication. The lowest biomass of goldenrods, as well as the highest biodiversity, was observed in plots where fresh hay, as a method of seed application was used. At the end of the experiment we observed that the cover of alien species was at the level which had no visible impact on bees and butterflies abundance and species richness (Moroń et al. 2019). The results reveal that five years after eradication the establishment of semi-natural grassland, with a reasonable low cover of Solidago, on formerly strongly invaded sites is possible.

Moroń D., Skórka P., Lenda M., Kajzer-Bonk J., Mielczarek Ł., Rożej-Pabijan E. & Wantuch M. (2019) Linear and non-linear effects of goldenrod invasions on native pollinator and plant populations. Biol. Invas. 21: 947–960.
Reid A. M., Morin L., Downey P. O., French K. & Virtue J. G. (2009) Does invasive plant management aid the restoration of natural ecosystems? Biol. Conserv. 142: 2342–2349.