Road 73 in Sweden: Followup studies of compensation measures

Project Road 73 had a high ambition to build a road that would be well adapted to the natural landscape. The aim of the project was also to reduce the shortcomings of adaptation on the existing road. A few years after construction several questions arose: How successful were the measures taken? Did they maintain and increase the biological biodiversity?

The road was one of the most dangerous roads in Sweden, called the "Road of death". The road went through areas rich in natural scenery, natural and cultural values, and also contained sensitive waterways. The road was a barrier for humans, wildlife and aquatic animal movement in the landscape. The challenge of building the new road was to have a holistic view of the landscape with nature, animals and humans in focus - a road in harmony with nature and animals.

In total 25 km four-lane highway, 5 interchanges and 33 bridges were built, as well as 35 km of local and private roads. The road was completed and opened in the summer of 2012. Examples of measures taken:

• Meadow vegetation establishment adapted to location and climate.

• Seeding and planting of host plants for insects and butterflies.

• Creation of new spawning area and migration routes for fish (Salmon trout).

• Compensation measures to protect and promote endangered insect species.


a) Seeding and planting of vegetation

In 2009 a stretch of the roadside of the highway in Överfors was planted with wild thyme (Thymus serphyllum) and was seeded with a mix of meadow plants. The presence of thyme and meadow vegetation was surveyed in 2015.

b) Bush removal to benefit insects

In 2012 measures to provide improved insect habitats were performed through bush removal and creation of sand blots in Älby. In 2015 an inventory was performed to follow-up the presence of insects. The inventory was focused on the group aculeate wasps, but other species were also sited.

c) Creation of new spawning area and migration routes for fish

In 2009 several migratory barriers in the stream Muskån were removed. The stream got a recreated course and a new spawning area was created. Population density of Salmon trout was followed by electrofishing between 2009 and 2012.


a) Seeding and planting of vegetation

• There was a high presence of wild thyme. Thyme was well established along with the sown meadow. In some parts Thyme dominated the field layer.

• The results showed that the area has a good ecological functionality with high nature conservation values for butterflies and hymenopterans.

b) Bush removal to benefit insects

• A total of 15 species of aculeate wasp were collected, two other species of aculeate wasps observed, one species of damselfly, 13 species of butterflies, 3 species of flies, and 5 species of beetles.

• Several species found are red-listed, and the area was assessed as valuable from a conservation perspective.

c) Creation of new spawning area and migration routes for fish

• The density of Salmon trout was high and did not vary over the years.

• Creation of spawning areas and the elimination of barriers had positive effects on the salmon trout population.

• The high densities of both juveniles and older fish suggest that the environment became very favorable.

mitigation, compensation, vegetation, waterways, insects