In front of us in the first photo is not a car tunnel, as it might seem at first glance. This is how the ecoduct looks like over the A7 autobahn near Baden-Württemberg Heidenheim. In total, there are already more than 80 special green bridges for wild animals (Grünbrücke, Wildbrücke) in Germany. The number of such elevated crossings, according to the plans of the government, will increase.
View of the motorway road near Heidenheim from the green bridge
Ecoduct near Heidenheim – how animals see this bridge
What are they needed for?
Green bridges are needed so that, for example, deer, wild boars, foxes, snakes and even moths (!) Can freely and safely for themselves and traffic participants, if we are talking about large animals, migrate or move between neighboring habitats there, where they were separated by highways or railways.
Green bridge over the A11 autobahn in Brandenburg
wild traffic
Usually, automatic cameras, including infrared cameras, are installed on green bridges to monitor wild traffic – to observe how quickly different animals begin to use the crossings and keep statistics. For example, this wolf was caught in a camera trap on the bridge over the A11 motorway in Brandenburg. In different places – the numbers are different, but we are usually talking about several thousand medium and large animals per year.
Hesse forester David Nöllenheidt
How to keep track of snakes?
By the way, this is what the camera trap looks like, the operation of which was explained to journalists by the forester from Hesse, David Nöllenheidt. To observe small animals, for example, invertebrates or snakes, on which sensors do not work, there are methods. For example, for ordinary snakes, boards are specially placed on bridges – so that they can hide under them, and then they regularly look under these boards.
Ecoduct near Friedrichshafen
Green Bridge over the so-called Baltic Autobahn (A20) in Mecklenburg
On the fresh snow
In winter, as seen in this photo of the bridge on the A20 autobahn near Bobice, it is also possible to study the footprints that wild travelers leave in the snow. This 320-kilometer highway was laid after the reunification of Germany. During construction, eight green bridges were immediately erected here.
Green bridge over federal highway B31 near Überlingen
Types of green bridges
The green bridge must be at least 50 meters wide. For pedestrians, cyclists and cars, they are usually closed. However, this bridge near Überlingen, as we see, is combined. A country road passes along it, but all the necessary conditions have been created for the animals – bushes and trees have been planted to protect the crossing from headlights and noise. Sometimes high walls are also installed along the edges. It should be noted that tunnels are also equipped in some places, but large animals usually do not use them – they are afraid to enter. To increase the chance of success, scientists recommend in such cases to build tunnels at least four meters high with a maximum length of 40 meters, using light-colored wall paint.
Red deer on a green bridge near Hünfeld
Benefits for nature and traffic safety
Such bridges not only return freedom of movement to animals, but also reduce the risk of accidents. Every year, about 200 thousand roe deer, 16 thousand wild boars and 3 thousand deer die on German roads. About 275 thousand insured events every year. The restoration of migration routes also contributes to the prevention of incest by allowing animals to find partners in neighboring territories.
Ecoduct on the Autobahn A17 near Dresden near Saxon Switzerland
Issue price
When laying new routes, such green bridges for animals are now usually planned in advance, then the construction is cheaper. Construction on existing tracks costs between 2.5 and 5 million euros. Environmental organizations welcome these projects, but at the same time they demand to build fewer roads that violate the unity of the habitat.
Autobahn A12 near Brandenburg Jakobsdorf
Green bridges in Europe
The first ecoducts appeared in the middle of the last century in France. Many of the Germans’ neighbors – the Netherlands, Switzerland, Austria and Luxembourg – started building green bridges much earlier, so Germany is now catching up, so to speak – especially since it has one of the densest road transport networks in the world.