Long-term vegetation changes in species-rich Nardus grasslands of Central Germany indicate eutrophication, recovery from acidification and management change as main drivers

• Published in: bioRxiv
• Main Authors: Peppler-Lisbach, Cord, Stanik, Nils, Natali Könitz, Rosenthal, Gert
• Format: Paper
• Language: English
• Published: Cold Spring Harbor Cold Spring Harbor Laboratory Press 18.12.2019
• Subjects: Acidification; Biogeography; Data processing; Environmental changes; Environmental factors; Eutrophication; Grasslands; Management; Nardus; Nitrogen; pH effects; Pollutants; Soil pH; Species composition; Species richness; Sulfur; Trends; Vegetation; Vegetation changes; Central Europe; Germany
• DOI: 10.1101/543512

Questions: Which trends and patterns of community change occurred in Nardus grasslands over the past decades in parts of the Continental biogeographic region in Germany? Are patterns and trends similar at local and regional scale? Do impacts of environmental changes on Nardus grasslands in Central Europe correspond to those identified in the European Atlantic biogeographic region? Location: East Hesse Highlands, Germany Methods: In 2012-2015, we resurveyed vegetation relevees on quasi-permanent plots initially surveyed between 1971 and 1987 and re-measured soil parameters. We tested for differences in species frequency and cover, mean Ellenberg indicator values, species richness and soil variables. Nitrogen and sulphur deposition data were analysed to evaluate effects of atmospheric pollutants. We used regression analyses and redundancy analyses to identify environmental drivers responsible for changes in species composition. Results: A regional scale, we found significant increases in soil pH, Ellenberg R and N values, plant nutrient indicators, forbs, species of agricultural and fallow grasslands. C:N ratio, Nardus grassland specialists, low-nutrient indicators and graminoids declined. Changes in species composition are related to changes in pH and management. There was a strong decrease in sulphur and a moderate increase in nitrogen deposition, whose local scale pattern did not correlate with changes in soil parameters. However, there was a statistical effect of local NHy changes on species composition. Conclusion: The findings indicate significant overall eutrophication, a trend towards less acidic conditions, insufficient management and abandonment, which are widely consistent across study areas and correspond to recent reports of vegetation changes and recovery from acidification in the Atlantic biogeographic region. We assume reduction in sulphur deposition during recent decades to be a major driver of these changes combined with increased nitrogen deposition and reduced management intensity. This suggests a large-scale validity of processes triggering changes in Nardus grasslands of Western and Central Europe.