Biotopes of national importance
Many previously widespread habitats are now severely reduced in area. To conserve the diversity of habitats and the rare and threatened species found in them, alluvial zones, mires, amphibian spawning sites and dry meadows and pastures are protected by national biotope inventories.
Habitats are populated by special species, which are adapted to the conditions that prevail there. If the quality of such sites changes, the risk arises that these specialised species will be lost. The widespread “generalist” species remain and new species migrate to the site. The original habitat and the associated specific species disappear and the ecosystem’s functions are lost.
poor
negative
The nutrient value did not change between the first (2012–17) and second (2018–23) surveys of raised bogs and fens. It decreased significantly in dry meadows and pastures. The improved values in dry meadows and pastures indicate successes in nature conservation (e.g. more nutrient buffer zones, conservation-compliant farming). Air pollution control measures may benefit the typical vegetation found in dry meadows and pastures. This type of vegetation is adapted to low-nutrient conditions.
Moisture values were found to be decreasing in both raised bogs and fenland and dry meadows and pastures. Moorland thus continues to dry out, a trend already observed in a predecessor project monitoring the success of moorland protection (’Erfolgskontrolle Moorschutz’, 1998–2006). Decreasing moisture levels in dry meadows and pastures can be seen as a positive development.
The amount of light decreased significantly in the raised bogs and dry meadows and pastures, and also tended to decrease in fenland (marginal significance). A decrease in the amount of light indicates shadier conditions. This might result from an increase in woody cover – which, in dry meadows and pastures and in fenland, could be caused by under-utilisation or because these areas are no longer cultivated. In raised bogs, which are not cultivated, the decrease in moisture may encourage woody cover growth and thus lead to shadier conditions.
Although there are positive developments in dry meadows and pastures, the ecological quality of raised bogs and fenland has continued to deteriorate. As the aim is not to allow any loss of quality and to improve the quality of endangered habitats, the status and trend are assessed as negative.
Since 2012, changes in biotopes of national importance have been recorded in a programme to monitor the effectiveness of habitat conservation in Switzerland run jointly by the Federal Office for the Environment (FOEN) and the Swiss Federal Institute for Forest, Snow and Landscape Research (WSL). On the basis of field surveys and analyses of aerial photographs, it can assessed whether biotopes are developing in accordance with the conservation objectives.
In order to detect changes in vegetation in raised bogs and fenland, in dry meadows and pastures and in water meadows of national importance, weighted random samples were taken from the relevant inventories ensuring that the (biogeographical) regions of Switzerland, the vegetation types, the different sizes of the geographical features and the various altitudes were adequately represented.
The first survey was completed in 2017, the second in 2023. Vegetation surveys were carried out in 441 dry meadows and pastures on a total of 2,149 10m2 permanent observation plots. 665 permanent observation plots were analysed in 86 fenland sites; 428 permanent observation plots were analysed in 59 raised bog sites. As the permanent observation plots are paired, i.e. data was collected on each plot for both the first and second survey, the statistical power of the tests is high. This also means that gradual changes can be detected at an early stage.
The presence of plant species and their degree of cover in the observation plots were determined in the field. For each species there are ecological indicator values showing how strongly the species reacts to certain environmental conditions. The mean values of the ecological indicator values are used to derive the nutrient, moisture and light conditions at the respective sites and to identify any statistically significant differences between the first and second surveys.
The assessment is derived from the significant changes in the avereage values (nutrient value, moisture value, light value) of all biotope types in accordance with the results of biotope protection monitoring. See Summary of the results of biotope protection monitoring (in German or French) : Resultate der Wirkungskontrolle Biotopschutz - Kurzfassung (PDF, 3 MB, 30.06.2025).
Further information
