"Close-up view", ecological value of the individual walls as habitats for various animals and plants
The colonisation of a wall consisting of newly broken, 'sterile' stones takes place from the neighbouring habitats. The radius of action of the animals, how fast they can move and what demands they make on the habitat are decisive here. This makes it clear how important it is for newly constructed walls to have a diverse environment and old walls that are already colonised. Therefore, renovations should be carried out in stages so that there are always old sections of wall in the vicinity and the recolonisation of the renovated sections of wall can take place without any problems. If intact sections of the old wall are left standing, mobile species find replacement habitat and recolonisation of the new wall can take place more quickly. Normally, the colonisation of dry stone walls by plants and animals proceeds without human intervention. Structural facilitation for safe migration of animals from the surrounding area can promote colonisation. It is also important that the passage through the crevice system of the wall to the soil is not interrupted. Furthermore, it may be possible to try to make the wall more attractive for animals and plants as a breeding and hibernation site by installing caves and passages. For example, the installation of nesting aids or caves in the dry stone wall can promote the settlement of cavity-nesting bird species. However, this should be approved by the competent cantonal authorities (Art. 19 NHG). Whether and how a settlement serves biodiversity must be clarified in each individual case.