The range of UIA database entries on threatened biological species as world problems has been considerably extended to explore possibilities of providing entry points to WCMC data. This involved the generation of over 13,000 new problem entries of the form "Threatened species of [taxon]". Entries have been hierarchically arranged according to the taxonomy of species. The entries opened at species level were for those species on the Red List of Animals (12,062 entries) and Red List of European Plants (1,057 of 40,000 on the List). Sources of data and taxonomy were the Red Lists (WCMC files), the Zoological Record (Biosis website) and Five Kingdoms (ETI, World Biodiversity Database CD-ROM).
Using a variety of sources available on the Internet, an experimental hierarchical framework, similar to that described above for species, was created for 303 threatened habitats/ecosystems and biomes. This was to explore the feasibility of interlinking individual species and protected areas through data on habitats. The habitat types were arranged in interlacing hierarchies corresponding to the classification parameters of the information source. For example, Holdridge’s set of the world's major ecosystems is classified by climate (temperature and rainfall). Other sources that were used classify habitat principally by vegetation structure or geographic factors. Sources used included the UNESCO terrestrial cover classification, the US Forest Service vegetation classification system and other north American sources, the Ramsar Convention wetland classification system and the UNEP/GRID world vegetation map. Not processed, due to their inaccessibility in English language format, were the CORINE habitat types for Europe (now accessible from the CD-ROM Natural Resources since obtained from the European Environment Agency (EEA).