Open Access

Claire Wolff, Kristin Gilhaus, Norbert Hölzel, Simone Schneider

• In Europe, semi-natural nutrient-poor ecosystems such as sand grasslands and heathlands have shown extreme declines in surface area and species richness within the last century. The remaining sites are hence of high conservation value. This study analysed the vascular plant species inventory of established and recently restored heathlands and sand grasslands in the southwest of Luxembourg. Analyses to explain differences in vegetation composition between “old” (remnant sites or sites restored a long time ago) and “new” (recently restored) sites in relation to environmental variables were carried out with DCAs and ANOVA/Mann-Whitney-U tests, respectively. The vegetation of old heathlands had few character species of typical heathland communities (Calluno-Ulicetea, Nardetalia), whereas new heathland sites were preponderantly marked by taxa of meso- or eutrophic grasslands and ruderal communities. New heathland sites mainly differed from old sites by higher soil phosphorus contents. Sand grassland vegetation was species-rich and composed by species of the Sedo-Scleranthetea and Festuco-Brometea. With increasing age of the sites, vegetation composition shifted to grass dominance with species of the Molinio-Arrhenateretea. New sand grasslands differed from old sand grasslands by higher soil pH, higher soil potassium content and lower graminoid cover. The differences between new and old sites of both habitat types could mainly be explained by successional processes or were a result of topsoil removal. In some cases, former anthropogenic impact at or in close proximity of restored sites resulted in unsuitable conditions, such as alkaline soil on former landfill sites or highly eutrophic soil due to intensive agriculture. Future management options for the study sites are discussed.
• Nährstoffarme Ökosysteme wie Heiden und Sandmagerrasen sind in den letzten Jahrzehnten in Europa stark zurückgegangen und noch vorhandene Flächen sind vor allem durch Versauerung und Stickstoffeinträge gefährdet (z. B. BAKKER & BERENDSE 1999, HÄRDTLE et al. 2009). In Luxemburg ist der Großteil der Heiden und Sandmagerrasen in einem schlechten ökologischen Zustand (SCHNEIDER & NAUMANN 2013, MINISTÈRE DU DÉVELOPPEMENT DURABLE ET DES INFRASTRUCTURES 2014a). Aufgrund dessen und wegen des starken Rückgangs werden hier seit einigen Jahren gezielt Renaturierungsmaßnahmen durchgeführt. Allerdings fehlt bisher eine Evaluierung dieser Maßnahmen und des Managements, weshalb in dieser Studie die Vegetation bestehender Flächen erfasst wurde.