Social-Ecological Signatures in Plant Species Composition Across Swiss Cities and Urban Green Space Types

Urban green spaces (UGS) are increasingly recognized as important reservoirs of plant diversity, yet the mechanisms shaping plant communities across different UGS types are still not fully understood—particularly how cultural contexts influence ecological patterns in cities. This study investigates how five common UGS types—private gardens, allotments, parks, ruderal areas, and real estate developments—contribute to urban plant diversity across three Swiss cities (Geneva, Zurich, and Lugano), each embedded in a distinct cultural region representing the French-, German-, and Italian-speaking parts of the country. By applying community ecology concepts, including alpha, beta, and gamma diversity, we quantified species richness, compositional variation, and overall diversity to better understand how UGS types and cultural environments jointly shape urban plant communities.

Our findings reveal substantial differences between the plant communities of the three cities. More than half of all recorded species were unique to a single city, while fewer than a quarter were shared across all three. These patterns indicate that cultural region, and potentially culturally influenced gardening practices, leave a strong imprint on urban plant assemblages. Differences were also evident among UGS types: ruderal areas and allotments supported particularly distinct communities, whereas private gardens, parks, and real estate areas displayed more similar species compositions. Moreover, species origin (native vs. non-native) significantly influenced both species richness and community dissimilarity, suggesting that the introduction and persistence of plants in cities depend not only on habitat type but also on the management decisions and gardening activities embedded within each cultural setting.

Together, these results highlight the importance of integrating cultural factors with ecological and planning considerations when examining and managing urban biodiversity. Understanding how UGS types and cultural contexts interact to structure plant communities can provide valuable insights for urban planners, landscape architects, and biodiversity managers. This research underscores the need for tailored, culturally informed approaches to designing and maintaining urban green spaces, ultimately supporting more diverse, resilient, and culturally reflective urban ecosystems.