So-called countryside ‘silent areas’ where sound is kept at between 35 and 40 decibels to avoid stress in animals have been disappearing, a survey conducted by the Volkskrant has found.

In the last ten years half the country’s provinces have authorised road construction and industrial parks in designated silent areas while increased noise from planes also drove up the volume. Some 15,000 of the designated 650,000 hectares now no longer qualify as a silent area, the paper said.

The idea to establish areas where only the sounds from activities necessary to maintain it are allowed, such as agricultural activity or tree felling, arose at the end of the 1990s. The aim was to protect animals against stress caused by noise.

If there is too much ambient noise, animals cannot pick up the sounds which may represent a threat to them, auditory cognition expert Tjeerd Andringa told the paper. ‘If an animal feels unsafe it will become stressed. Silence is important and necessary, including for people. A long-term lack of silence can affect the immune system and lead to heart disease, for instance.’

The province which has sacrificed most of its silence is Flevoland where 80% of designated areas of silence no longer qualify. The only provinces found to have increased their stock of silence are Noord Brabant and Drenthe, albeit by only 7% and 4% respectively.