Green facades support biodiversity in urban environment : A case study from Poland

Green walls, along with green roofs, parks, and vertical gardens, belong to the green infrastructure of cities, which will encompass the majority of humanity in the coming decades. Green infrastructure benefits both urban residents and nature in the urban landscape, although there is no scientific consensus on the extent to which green walls, especially green facades, impact biodiversity in cities. This study examined the influence of green facades on the richness of mammals, birds, and invertebrates, considering the species and age of the plants comprising the green facade in a medium-sized city located in southwestern Poland. It was found that the implementation of green facades significantly enhances species’ biodiversity compared to non-vegetated walls. Four synanthropic bird species were nesting on green facades: Eurasian collared dove (Streptopelia decaocto), blackbird (Turdus merula), house sparrow (Passer domesticus) and woodpigeon (Columba palumbus). For the beech marten (Martes foina), the green facades are a hunting ground for birds and their eggs. This simple and effective method of creating green walls provides benefits to local wildlife by creating habitats, shelter, and foraging opportunities for selected species. However, it is difficult to determine whether green facades contribute to the formation of ecological corridors in urban environments. The study also examined the social aspect related to the establishment and maintenance of green facades on the surveyed buildings.