Das Projekt "Ein einheitliches Datenmodell fuer Biologische Sammlungen (CDEFD)" wird vom Umweltbundesamt gefördert und von Universität Berlin, Zentraleinrichtung Botanischer Garten und Botanisches Museum Berlin-Dahlem durchgeführt. Researchers in chemistry, molecular biology, ecology and many other branches of science use materials obtained from organisms as the base of their studies and subsequently store their research results in databases. Their source material often consists of samples taken from natural history collections, or it is vouchered in such collections to ensure proper identification of the organisms. This material includes plant, animal, or paleontological specimens in natural history collections, culture collections of microbial strains, botanic- or zoological garden collections, natural product collections, etc. In almost all of these fields, Europe owns the most extensive collections of such specimens worldwide. Electronic inventories facilitate access to these resources. To achieve interoperability of present and future databases, common data models and standards are needed. At the outset of the project, the objective of CDEFD (original project title: A Common Datastructure for European Floristic Databases) was to develop project-independent structures to be used in the design of floristic databases and databases including floristic data. In the course of the project, this was extended to include biological collections in general, because it was realized that all objects or samples obtained from organisms share the same core data structure. By means of a CASE (Computer Aided Software Engineering) program the results were recorded in a constantly updated information model, which consists mainly of diagrams depicting the complex data structures. Accompanying text and tables further define the contents and meaning of structural elements. The CDEFD datamodel for biological collections together with the related (OPI Global Plant Checklist Taxonomic Information Model) provide a complete framework for biological collection and oberservation data. CDEFD analysed collection management, taxonomic and other identifications. Although a tentative detailed datastructure for geographic and ecological data relating to collection sites has been included in the model, the group came to the conclusion that commercially available geographic information systems (GIS) should be used whenever a detailed cover of such information is requested. GIS systems can be linked to relational databases, so that integration with the model for collection data can be achieved. Links with information outside the realm of collection data were evaluated in detail by looking at the structure of chemical data (secondary metabolites), karyological data, and ecophysiological data. This information was modelled from two points of view: The data about organisms produced by research studies, and the data which is used during the study itself. The latter discussion leads to the development of a generalized model for experimental studies. The model supplies guidelines for the definition of data fields and thus facilitates the discussion on data standards.