Open Access

Wolfgang Willner, Norbert Sauberer, Markus Staudinger, Viktoria Grass, Reinhard Kraus, Dietmar Moser, Harald Rötzer, Thomas Wrbka

• As second part of a series focusing on the Pannonian grasslands of Austria, we present a detailed classification of the grasslands of the Vienna Woods (Wienerwald). This region, although geographically belonging to the Alps, has strong floristic affinities to the Pannonian Basin. The eastern slopes of the Vienna Woods are a hotspot of xero-thermophytic vegetation and exhibit the highest vascular plant species richness in Austria at a scale of 3' x 5'. We used the TWINSPAN classification of a large data set reported in the first part of this series as starting point. Relevés that were considered as misclassified at the level of alliances were manually re-arranged. From this table, an excerpt containing only the relevés of the Vienna Woods was used for the present study (1055 plots). We re-classified the relevés preliminary labelled as Arrhenatherion with another TWINSPAN run. Clusters for which no ecological difference could be detected were merged. The final delimitation of associations and subassociations was achieved by adjusting their diagnostic species so as to get units that were most informative in terms of environmental conditions. All re-arrangements were based on the summarised cover of diagnostic species within individual relevés. As a result, the grasslands of the Vienna Woods are classified within 22 associations (plus two subassociations) belonging to ten alliances and four classes. Within the Seslerio-Festucion pallentis, a new association Scorzonero austriacae-Caricetum humilis is described. The semi-dry grasslands of the study area previously classified as Onobrychido-Brometum are de-scribed as new association Filipendulo vulgaris-Brometum erecti and assigned to the Cirsio-Brachypodion. The Anthoxantho-Agrostietum tenuis is reported for Austria for the first time, and its syntaxonomy is discussed within a broader geographical context.
• Nachdem im ersten Teil dieser Serie ein allgemeiner Überblick über die pannonischen Rasengesellschaften Österreichs gegeben wurde (Willner et al. 2013), legen wir hier nun eine detaillierte Klassifikation für das Gebiet des Wienerwalds vor. Obwohl geographisch zu den Alpen gehörig, weist der Wienerwald enge floristische Beziehungen zum Pannonischen Becken auf. Die Wiesen und Trockenrasen dieser Region zählen zu den best erhaltenen in Österreich und dank der in den letzten zwanzig Jahren durchgeführten zahlreichen Freilanderhebungen auch zu den best dokumentierten. Allerdings lag bislang keine befriedigende Klassifikation dieser Pflanzengesellschaften vor. Die 2005 erfolgte Einrichtung des Biosphärenparks Wienerwald, und nachfolgende Pläne für eine flächendeckende Kartierung des Gebiets machten die Erarbeitung einer solchen Gliederung dringend notwendig. Dies gab – neben Unklarheiten in der Zuweisung der pannonischen Rasengesellschaften zu Natura 2000-Lebensraumtypen – den Anstoß zu der vorliegenden Untersuchung.