From all sites representing dry grasslands, raised bogs and fens, as well as flood plains of national importance, a subset of about 800 sites was selected. In these, extensive vegetation surveys are conducted on a regular six-years cycle. The gathered data is used to calculate various indicators which evaluate the state and the development of these sites with respect to changes in habitat quality.
The sub-sample of all sites of national importance was selected using a stratified random sampling design which weighted rare vegetation types higher than common ones to ensure a more even representation of vegetation types among biogeographical regions and along elevational gradients. The sample includes approximately 400 dry grassland sites, 260 raised bogs and fens, and 125 riparian areas and flood plains of national importance. In total, about 7000 permanently marked circular 10 m2 plots were established in the first sampling period from 2011 to 2017. In these plots, all vascular plants are sampled every six years. In riparian areas and flood plains, shrubs and trees are sampled in an additional 200 m2 plot centered on the core 10 m2 plot. In raised bogs and fens, soil-dwelling bryophytes (i.e. mosses, liverworts, hornworts) are sampled in addition to vascular plants.
Based on the data assessed, conclusions can be drawn both at the national-level and between biogeographic regions concerning ecological changes and their causes (e.g. eutrophication, intensification/extensification, succession). Moreover, as the methods used to assess the vegetation are comparable to those applied in other national monitoring programs (e.g. Biodiversity Monitoring Switzerland [BDM], and the monitoring Agricultural Species and Habitats [ALL-EMA] schemes), the three monitoring programs complement each other perfectly. Whilst BDM reflects a random sample of the "normal landscape" of Switzerland (including settlements) and ALL-EMA focusses upon a wide range of (mesic) agricultural areas representing different land-use intensities, WBS instead focusses on rare vegetation types in protected areas. WBS sites represent a range of habitats with diverse ecological conditions; sites include dry steppe habitat types in the inner-alpine dry valleys, ranging over dry to mesic vegetation types to wetlands, floodplain forests, raised bogs and fens. Thus, the whole ecological and land-use intensity gradient of various habitat types in Switzerland is covered, allowing synthesis analyses to answer more general questions of interest to the broader public.
The floristic data is transferred to the national data centers, i.e. Info Flora (National data and information center of the Swiss flora) and Swissbryophytes (National data center of Swiss bryophytes) and is used for other national projects, such as the revision of the national Red Lists of endangered species. Access to the data for the cantons is provided via the virtual data center (VDC). In addition, data are available for specific research projects on request.