Effect of noise measures for birds

Background

The impacts of traffic noise on birdlife are well proven. Dose-effect relationships and critical levels are described in scientific literature. The impacts, however, differ between species, ecosystems and type of noise, and may not always be significant.

On the basis of previous TRIEKOL research, the Swedish Transport Administration (STA) developed a method that points out road stretches where the traffic noise exceeds critical levels and impacts species of conservation concern. In addition they pointed out habitats where noise prevention should be prioritized. 

While a number of measures to reduce noise for people are used (e.g. screens, berms, adapted paving, traffic calming), their performance for birds have not been tested. Mitigating traffic noise in important bird areas is expected to add significantly to the cost of road/railway construction and maintenance.

To enable cost-effectiveness analyses of noise reduction in important bird areas, the reduction effect of different measures need to better known, and combined with available cost estimates for the different types of measures.

Acoustic ecology is an emerging field, with important potential ramifications for the planning and management of roads and railways. 

Activities

Available data from the previous BACI studies on birds along the Botniabanan railway was compiled, (re-)analyzed and published in a scientific manuscript, to produce a final insight in the main results regarding the railway´s impact on birds.

An important aim of this subproject was also to study the effects of noise mitigation (noise screens) along existing road stretches near important bird habitats. Noise screens were to be erected on a number of road bridges in connection with road upgrading projects, and bird abundance censused before and after the mitigation. However, due to practical limitations no study objects could be achieved during the program period, and this part of the subproject had to terminate without results.