All dragonfly species native to Europe were included in the assessment. Five species with marginal occurrences in Europe were classed as Not Applicable, and were therefore not assessed (Anax junius, Pantala flavescens, Platycnemis subdilatata, Trithemis arteriosa, Trithemis kirbyi). The taxonomy largely follows the Global Species Database Odonata (Van Tol 2006) available at: www.odonata.info, albeit with minor deviations. Subspecies were not assessed, with the exception of those of Onychogomphus forcipatus and Cordulegaster helladica.
For each taxon the following data were entered into the Species Information Service (SIS) database:
Preliminary assessments of all European dragonfly species were conducted by Jean-Pierre Boudot and Vincent Kalkman, using existing literature, data sources and personal knowledge.
Eleven experts of European dragonflies were invited to attend a five-day regional review workshop, held in Faro (Portugal) in April 2008. The invited specialists (Rafał Bernard, Jean-Pierre Boudot, Klaus-Jürgen Conze, Geert De Knijf, Elena Dyatlova, Sónia Ferreira, Miloš Jović, Vincent Kalkman, Jürgen Ott, Elisa Riservato and Göran Sahlén) were selected so that knowledge of all parts of Europe was available during the workshop.
Preliminary species summary reports were distributed to all the participants before the review workshop, so that they could check the presented data and prepare any suggested alterations that they would like to discuss at the workshop. The preliminary assessments were reviewed during the workshop, and new information was added to the species summaries and maps. Red List Categories were then defined for each species at the European and EU 27 levels.
Following the review workshop, the data was edited, and unresolved questions were settled through communications with the workshop participants. Consistency in the use of the IUCN Criteria was checked by IUCN staff from the IUCN Red List Unit and the IUCN/SSC Dragonfly Specialist Group.
The resulting finalised IUCN Red List assessments are a product of scientific consensus concerning the status of the species backed by relevant literature and data sources.