To protect precious habitats and the biodiversity, Switzerland designated about 7000 sites of national importance. These sites are legally protected and include mires (fens and raised bogs), dry grasslands, and flood plain habitats as well as amphibian breeding sites. In 2011, the Federal Office for the Environment (FOEN) and the WSL Swiss Federal Research Institute launched the joint project "Monitoring the effectiveness of habitat conservation in Switzerland WBS" to observe developments and changes in these sites.
Die Wirkungskontrolle Biotopschutz Schweiz (WBS) ist ein seit 2011 laufendes Programm des BAFU und der WSL. Sie untersucht mittels Luftbildinterpretation sowie floristischen und faunistischen Felderhebungen Veränderungen in den Biotopen von nationaler Bedeutung, den wichtigsten Knoten der Ökologischen Infrastruktur: Trockenwiesen und -weiden, Hoch- und Flachmoore, Auen (inklusive alpine Schwemmebenen und Gletschervorfelder) und Amphibienlaichgebiete.
The sites of national importance are a crucial element of the network of protected sites in Switzerland. The WBS is using remote sensing approaches as well as extensive floristic and faunistic field surveys to calculate various indicators in order to evaluate whether these sites are developing in line with their conservation targets and assess whether the area and quality of habitats is being maintained. These indicators permit the identification of negative changes at both national and regional level, such that appropriate measures can be initiated. The WBS is operated as a long-term program. The first survey period was finished in 2017, the second period started in 2018 and will be terminated in 2023.
First analyses show that raised bogs and fens have become drier over the past two decades. Furthermore, fens, raised bogs, and dry grasslands are experiencing shrub encroachment and increased colonization of nutrient-loving species. In addition, the national amphibian breeding sites have lost an average of one amphibian species per site. However, there were also positive developments; for example, in the raised bogs of the Swiss lowlands, woody cover decreased and the losses of common amphibian species have been compensated by the observation of new species in amphibian breeding sites. Moreover, populations of rare amphibian species have also stabilized in some cases.
These positive findings demonstrate that conservation measures are effective and should therefore be continued or even enhanced.