A plant checklist for the Schlosspark Laxenburg: ecological jewels of a Habsburg legacy

The Schlosspark Laxenburg is located in the Vienna Basin south of Vienna. Extended over approximately 280 hectares in area, it is one of the largest parks of its kind in Central Europe. It was first mentioned in the 13th century as a hunting ground that formed part of the estate of a large house. Its present design as English landscape garden took shape in the 18th and continued into the 19th centuries under Joseph II and Francis II I. In addition to recreational areas, there are large near-natural areas, especially meadows and forests. Due to the occurrence of rare species (especially birds and beetles) and unique habitats, the Schlosspark Laxenburg was designated as part of the Natura 2000 site "Feuchte Ebene- Leithaauen" since 2009 and 2011 respectively. Until now, surprisingly little was known about the inventory of vascular plants in the park. Therefore, surveys were carried out between 2023–2025, in order to assess the floristic composition of the Schlosspark Laxenburg. A total of 484 taxa of wild or feral plants were recorded (478 species, four natural hybrids and two subspecies). Of these, 422 are considered native to Austria (including archaeophytes), 34 are established neophytes (only detected in Austria after 1492) and 28 are considered to be casuals (not permanently established). Forty species are listed as being under threat in Austria according to Red List categories "Endangered" and "Vulnerable". The discovery of the Habitats Directive species Klasea lycopifolia, which grows in three meadows in the Schlosspark Laxenburg, is an exceptional find. For this species, the province of Lower Austria holds the entire responsibility for its conservation in Austria, as the only other four known localities of this species in Austria are also found in this federal state. We consider a wet meadow in the northeast of the Schlosspark to be particularly valuable, as 13 Red List plant species were recorded here (including Allium angulosum, Lythrum virgatum, Teucrium scordium, Thalictrum flavum and Viola pumila). We discuss the importance of the Habsburg Empire in preserving species that are rare in Austria and highlight suggestions for Schlossparks in Austria to increase the knowledge of the plants present there, and their conservation.