An overview of the state of biodiversity in Spain: developing a National Red List programme

The Spain Species Specialist Group of the IUCN Species Survival Commission, established in 2024, comprises c. 150 specialists in 18 taxonomic working groups. Among its aims is the assessment of the status of Spanish species for the IUCN Red List of Threatened Species. We review the Master List of Wild Species in Spain (63,981 species) and analyse taxonomic bias and the low number of these species included in the IUCN Red List (2,687 species) and Spanish legislation (935 species in the List of Wild Species under the Special Protection Regime and the Spanish Catalogue of Threatened Species). Only 7.3% of species legally protected in Spain are also included in the IUCN Red List. We also document considerable variation in the availability of specialists and information between taxonomic groups. Terrestrial vertebrates and butterflies are the best-studied taxa, and other insects, spiders, molluscs, algae, mosses and liverworts are the least studied. To overcome these shortfalls, we propose a monitoring plan focused on a broad taxonomic sample of species representative of different habitat types and biogeographical zones. The aim is to develop a standardized National Red List using IUCN criteria, to assess the risk of extinction of species and monitor trends in the status of biodiversity in Spain. This could be achieved with support for training specialists in lesser-known taxonomic groups and the long-term commitment of the associations involved in this programme. This study could be a model for the establishment of programmes and national Red Lists for other National Species Specialist Groups.