All amphibian species native to Europe or naturalised in Europe before 1500 A.D. were included in the assessment. Species introduced to Europe by man after 1500 A.D. were considered by the assessment, but were classed as Not Applicable. Similarly, species that are of marginal occurrence in Europe were classed as Not Applicable. The European Species Assessment uses Amphibian Species of the World (Frost 2008) as its default taxonomy for amphibians. Distinct subpopulations and subspecies of amphibians within Europe were not individually assessed as part of this project.
For every amphibian species native to Europe or naturalised before 1500 A.D, the following data were compiled.
These data were based on initial information gathered as part of the IUCN Global Amphibian Assessment (IUCN, CI and NatureServe). Much of this earlier material originated during an earlier review of the conservation status of reptiles and amphibians in the Mediterranean basin (Cox et al. 2006). All species had their global status assessed according to the 2001 IUCN Red List Categories and Criteria: Version 3.1 (http://www.iucnredlist.org/info/categories_criteria2001). Preliminary species summary reports, distribution maps and global assessments were distributed to all the participants before the workshop to allow them to review the data presented and prepare any changes to the data.
Expert herpetologists for Europe were invited to attend a five-day regional review workshop, held in conjunction with an IUCN review of reptile and amphibian species of the Wider Caucasus, at the Grida City Hotel in Antalya, Turkey in September 2008.
Focused working groups were organised to efficiently review identified geographical sets of species. New information was added to the species summaries and maps, and corrections to existing data were made. Preliminary Red List Assessments for each species were then made at the global, European and EU 27 levels.
Facilitating staff from the IUCN Red List Unit and the IUCN/SSC-CI/CABS Biodiversity Assessment Unit evaluated the assessments to check they complied with the guidelines for application of the IUCN Red List Categories and Criteria and included the most up-to-date, comprehensive information.
Following the review workshop, the data were edited, and outstanding questions were resolved through communications with the workshop participants. The post-workshop draft assessments were also made available on an FTP site to allow the participating scientists to make any final edits and corrections.
The resulting finalised IUCN Red List assessments are a product of scientific consensus concerning species status and are backed by relevant literature and data sources.