Urban Vegetation of the Transport Technosphere: A Case Study of the Stuttgart Hauptbahnhof Railway Station (Germany)

The reconstruction of the Stuttgart Hauptbahnhof railway junction, known as Stuttgart 21, is a very large and long-term infrastructure project. The gradual extension of the project implementation creates a specific time period during which atypical vegetation management in the trackbeds takes place. The vegetation of the trackbeds of the current station includes a total of 68 plant taxa, with Erigeron bonariensis L., Geum urbanum L. and Senecio inaequidens DC being significantly represented, for example. The limited level of disturbance within this “time window” creates favorable conditions in particular for the development of woody plants and lianas, such as Acer campestre L., Acer pseudoplatanus L., Ailanthus altissima (Mill.) Swingle, Clematis vitalba L., Ficus carica L., Hedera helix L. and Sambucus nigra L. The detected spectrum of plant taxa also indicates the formation of a diverse mosaic of microhabitats, which allows the coexistence of species with different ecological requirements. The assessed railway lines also provide space for the occurrence of non-native species, many of which are capable of effective wind dispersal and can subsequently colonize surrounding urban areas. Habitats with a time window of limited vegetation management may represent a poorly described factor influencing the spread of some taxa in the technosphere. The knowledge gained may contribute to a better understanding of the population dynamics of individual taxa and their potential for further spread.