Expert SystemDigital habitat maps depict the absolute area per km2 of various habitat types that are relevant for faunistic species. Maps are generated with a GIS-assisted overlay technique that merges various digital thematic map layers, i.e. landuse data, vegetation maps, biotope inventories, bioclimatological maps etc. The habitat types follow the habitat classification of the Swiss Center for faunistic mapping (CSCF). The habitat maps are the input to the expert model that describes habitat requirements of more than 3000 species (retrieved from the faunistic database of the Professorship for nature and landscape conservation at ETH). In contrast to approaches that relate presence/absence data to biophysical properties, we do not use survey data in a statistical or predictive model. We generate digital distribution maps by calculating the relative area of suitable habitats for each grid cell (1km2) as the average area of all habitat types that are potentially able to host the corresponding species. Probability of occurrence is assumed to be linearly related to the relative area of suitable habitat. Survey data are used to check the performance of the expert system. |
