Conference proceedings article
Long-term vegetation changes in Nardus grasslands in the UNESCO biosphere reserve Rhön



Publication Details
Authors:
Stanik, N.; Rosenthal, G.
Editor:
University of Marburg,
Publisher:
Universität Marburg, Fachbereich 17 - Biologie
Place:
Marburg
Publication year:
2016
Pages range:
TBD
Book title:
46th Annual Meeting of the Ecological Society of Germany, Austria and Switzerland (GfÖ),
Languages:
English

Abstract

Semi-natural Nardus grasslands (Violion caninae) are currently highly endangered by eutrophication, land-use intensification and abandonment in many mountain areas. Species-rich forms of these grassland communities are a target habitat of the EU Habitats Directive and therefore claim particular attention by nature conservation on national and EU level. We analysed the development of Nardus grassland sites in the biosphere reserve Rhön (both Hessian and Bavarian part) that were first documented in 1971 resp. 1986/87 by vegetation relevés and that were re-assessed in 2014/15. Our results show that only one third of the Nardus grasslands had maintained their former status. Other sites, however either developed into more productive mountain hay meadows (Trisetion) due to eutrophication and intensification, or into tall forb (Poa chaixii-Deschampsia cespitosa-community) and pioneer forest communities due to abandonment. Some sites were even afforested with spruce. Unexpected results are that even on sites that could still classified as Nardus grasslands, showed gradual and directed changes, i.e. the decline of nitrogen-sensitive species and the increase of nitrogen demanding species. Especially, the bryophytes diversity decreased and only some nitrophilous moss species became dominant. Soil analyses supported these findings by improved nutrient supply (esp. N), narrowed C/N coefficients and of the mineralisation of the organic matter. Our results suggest that the floristic changes have expired during the last decades, and are likely to continue, although the N deposition rates in the Rhön are lower than the maximum tolerated critical loads for this ecosystem type. Furthermore, the results show that the highly subsidised management of the Nardus grasslands in the Rhön (due to specific agro-environmental schemes) did not lead to the desired goal under the current environmental and socio-economic conditions and may not in the future. We conclude the need for an adapted landscape and conservation management in the UNESCO biosphere reserve Rhön that aims to counteract the processes of vegetation change driven by eutrophication and land-use change processes.



Authors/Editors

Last updated on 2018-31-10 at 14:42