1. MAPPING THE MULTISPECIES CITY
Our four selected species belong to the Forest Subnetwork. They are the Great Spotted Woodpecker, the Red Squirrel, the Blue Tit and the Hazel Dormouse. The food regime of these species is almost identical : berries, nuts, fruits, small insects, flowers… The predators of the four are mainly raptors, domestic cats and owls.
Within the guild, the activity period is mainly diurnal, except for the Hazel Dormouse being active during the night. The Red Squirrel and the dormouse both hibernate, mainly in cavities in the ground covered in leaves or in three holes. Sometimes these two species will nest in one of the Woodpecker previous carved hole.
The common main threat of the four species is habitat fragmentation, even increased for the Red Squirrel and the Hazel Dormouse as they need trees to move around, and preferably never go down to the ground.
As a site, we selected the Vallon, north of Lausanne. The Vallon is a valley that divides the Sauvabelin forest in two. We selected this site because it is a valley with a forest on each side : we wanted to work on creating a biological corridor using topography, and possibly, existing roofs.
2. ON SITE ANALYSIS
We were able, using a Grasshoper script and data from Open Street Map, to identify the threats and opportunities of our site. A common threat is the road presence, causing noise disturbance, especially problematic for hibernating species such as the Squirrel and the Dormouse. A big opportunity the site has to offer is the variety and quantity of trees.
We built an inventory of the tree species present on our site, along with the affinities they have with animal species. For example, dormouses will enjoy sour cherry trees that provides them with a fruit supply. Red squirrel will tend to enjoy conifers more, their main food supply being the various nuts these tree produce.
We developed a plant inventory as well, full of various berries and a shelter for our species.
The main vision of the project runs throughout the years : roofscapes will be modified to welcome plants growth. In the first years, the intervention will serve as animal stepstones. While the trees grow, the network will become more and more dense, creating a real corridor passing through the roofs and in the trees.
3. SYSTEMIC PLANNING
To create this ecological corridor, we worked with algorithms. Using the existing trees, we then added some where necessary, based on distance between the canopies. The parts where trees could not be planted will become our architectural intervention.
The rooftop plan was also parametric : considering the existed and projected trees, we offset them to place the first pots inside the structure. We then amplify and modify this first pot network to fit human functions, according to the building’s program.
4. BUILDING A CONTINUOUS CANOPY
The main two buildings we decided to apply these principles to are a theatre, with a curved plan and a high-pitched roof, and an adult rehabilitation centre, with a flat roof.
Using the herbarium, we were able to chose which trees fit best for ground imprint. Some plants of the herbarium are climbing purposefully, to help the animals' circulation.
In the theatre, the openings create a variety of open, closed and semi-opened spaces that are adapted to functions : theatre rehearsal room, ballet room, a café…
The hospital structure is made to stimulate strolling around the plants pots, as nature presence is proven to be beneficial to recovering patients.
Architecturally, the flat roof is enhanced by a new wooden structure, with depth where the pots are, helping them to climb on the structure.
On the high-pitched roof, the existing carpentry is modified and adapted to the intervention, while keeping the original aesthetics.