Dry grassland sites are species-rich habitats characterised by their use for agricultural purposes. The distinctive characteristics of these habitats vary enormously, depending on the natural region to which the site belongs, and the cultural history of the site. About 40 % of plant species growing on dry sites, and in some cases over 50 % of the animal species are however included in the red lists, and are endangered or threatened with extinction. This is a result of the continuous decline in the area of dry grassland. It is estimated that about 90 % of dry grassland in Switzerland has disappeared over the past 60 years.
Therefore, based on the Federal Law on the Protection of Nature and Landscape, the most valuable areas are being mapped and evaluated, as part of a project called "Dry Grassland in Switzerland" (DGS), so that with a federal inventory these sites can be given the increased protection provided for by law.
A specific, target-oriented survey method has been developed to meet the needs of the project as closely as possible. The central part is the differentiated mapping of the vegetation, using aerial photographs, and a modular vegetation key. Since 1995, the method has been applied in different parts of Switzerland, and in different natural regions, and it has been progressively added to, and improved. In parallel with this, a procedure for the evaluation and classification of dry grassland has been developed, based on the model of utility analysis. This approach enables ideas on evaluation to be implemented in a way that is transparent and comprehensible, using criteria that vary in quality and accuracy. The present report describes both these methods in their developed form. In addition, the procedure chosen for singularities in the DGS project is presented, as well as some initial results.