In practically all our cities, the impact of concrete on biodiversity is devastating: the Artificial soil coverage It reduces the natural areas available for flora and fauna, increases temperatures and irreparably compromises the ecological balance.
A context to say the least asphyxiating, where the green roofs can represent an effective solution At least to try to mitigate the effects of cementing and offer a precious habitat to biodiversity.
What are green roofs and how do they work?
The green roofs are nothing but vegetable roofs installed on buildings and homes that replace the waterproof surfaces with layers of earth, plants and sometimes real ecosystems. They can be extensive, with a thin layer of low maintenance vegetation, or intensive, real hanging gardens that also host trees and shrubs.
These green spaces not only improve the energy efficiency of buildings, reducing the need for conditioning and heating, but also act as shelters for pollinating insects, birds and small animals, restoring an ecological balance altered by urbanization.
In addition, green roofs help to retain rainwater, reducing the risk of flooding and lightening the pressure on city sewage networks.
The case of Basel, a successful model
A virtuous example of integration of green roofs in a strategy of protection of urban biodiversity is represented by the Swiss city of Basel. Since the 90s, the city has adopted ambitious policies to promote the installation of green roofs on public buildings and has become the first city in the world to make green spaces a legal requirement for new buildings.
As part of the Basel strategy for biodiversity, in fact, for 15 years The green spaces are mandatory in all new buildings and renovated with floors roofs. Since then, more than 1 million square meters of green roofs have been built, making it the leading city in the “reviving” of its urban spaces.
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What Basel distinguishes from other cities is the scientific and structured approach with which the green roofs have been designed. In collaboration with biologists and ecologists, The city has developed roofs designed specifically to encourage biodiversityincluding native plant species and materials that simulate the natural habitats of local insects and birds.
The results were surprising: research showed that the green roofs of Basel host over 175 species of plants and a significant variety of pollinating insects, including wild bees and butterflies, which otherwise would not find space in urban contexts. In addition, these ecosystems reduce the so -called “urban heat island effect”, lowering city temperatures and improving air quality.
Basel, therefore, also shows that green roofs are not only an aesthetic or energy choice, but one real conservation strategy of urban biodiversity. For other cities, replicating this model would mean improving climatic resilience, increasing urban green and offering new opportunities for the nature of harmoniously integrating into the city fabric.
Promoting the diffusion of green roofs means rethinking the way we design our cities, making them more sustainable, liveable and size of nature.
