The importance for biodiversity and conservation in the SACC/SPA Illas Cíes (ES0000001) is endorsed by the identification of a large set of habitats and species of community interest in the Master Plan of the Natura 2000 Network of Galicia (Ramil-Rego et al. 2012), approved by Decree 37/2014, which is the basic planning and network management instrument for Natura 2000 Spaces in Galicia. The Plan establishes a set of objectives and management measures for the natural spaces that are included in its scope of application, in order to ensure a favorable state of conservation of the types of natural habitats and of the species of community interest of the CD 92/43/EEC and CD 2009/147/EC. According to the diagnostic information of the Master Plan of the Natura 2000 Network of Galicia, the ZEC/ZEPA Illas Cíes (ES0000001) houses 23 different types of habitats of community interest in its territory (Annex I of CD 92/43/EEC) , of which 4 are considered priority (1150*, 2130*, 2150* and 6220*). In other words, within this space, which represents 0.28% of the Natura 2000 Network of Galicia, there is representation of 32% of the total habitat types of community interest identified for Galicia and 22% of the priority types in the Autonomous Community (Ramil-Rego et al. 2008a, b). This large list of habitat types, with special attention to the variety of coastal habitats present, contribute to improving the connectivity of natural and semi-natural habitats, functioning as essential link points for the migration and genetic exchange of wild species.
The insular and coastal nature of this territory means that the largest group of habitats is that related to Coastal habitats and halophytic vegetation, with 10 different types identified (of the 13 identified in Galicia, that is, 77%), and the group of Maritime and Continental Dunes that has 7 types of habitat that represent all (100%) of the dune habitats identified in Galicia. Therefore, the habitats belonging to the dune systems of the islands stand out, which are in contact with other types of coastal habitats, which represent a set of fragile ecosystems in the face of the threats identified in this project (see form B2d), which indicates the importance and interest that in the SAC/SPA Illas Cíes (ES0000001) represents the contact and continuity of these types of habitat from the point of view of the conservation of biodiversity and natural heritage.
However, consulting the environmental mapping of the Natura 2000 Network Master Plan, made publicly available by DXPN, makes it possible to verify that the types of habitat that occupy a larger area, apart from the types related to coastal waters (1110 , 1140, 1160, 1170), are the community interest rate 4030 with 190.17 ha (19% of the SAC/SPA), the 1230 rate with 115.20 ha (12% of the SAC/SPA), type 8230 with 105.52 ha (11% of the SAC/SPA), priority type 2150* with 92.36 ha (9% of the SAC/SPA), and type 2130* with 16.64 ha (2% of the SAC/SPA). In other words, the habitat types with the greatest surface representation of the SAC/SPA Illas Cíes (ES0000001) make up an extensive continuous complex of high conservation value and community interest, being in contact with the transition formed by types 2130* and 4030, addressed by LIFE INSULAR in this document. The dune ecosystems of the type 2130* contact, following a horizontal axis, with the cliffs of the type 1230, while vertically catenally they contact the coastal thickets of the type 4030 and the dune thickets of the 2150*, which in turn are also found in contact with type 1230. These 3 types of habitat (1230, 2150*, 4030), in turn, include important representations of siliceous rocks of type 8230.
For all of the above, the representation of coastal and insular habitats of the SAC/SPA Illas Cíes (ES0000001), together with those of other Atlantic archipelagos in the Natura 2000 Network of Galicia (Ons, Sálvora), also included in LIFE INSULAR, are among the best in the entire NW Iberian.
In terms of flora and fauna, the SAC/SPA Illas Cíes (ES0000001) has a high number of species of interest for conservation, with a total of more than 90 species with some category of European, state or regional protection, in its majority corresponding to birds, being a place that houses various colonies of migratory birds. A total of 13 taxa are included in Annex II of CD 92/43/EEC, where it is worth noting the presence of the priority species Caretta caretta, the herpetofauna species Discoglossus galganoi and Chalcides bedriagai, or aquatic mammals such as Tursiops truncatus and Phocoena phocoena.
The diversity of invertebrates in this archipelago is notable, especially terrestrial but also aquatic taxa, which find The diversity of invertebrates in this archipelago is notable, especially terrestrial but also aquatic taxa, which find in this space an ideal habitat for their populations, since it is possible to identify a total of 8 species of this group, which represents 67 % of invertebrate taxa of interest for the conservation of Natura 2000 spaces in the coastal area of Galicia. It is possible to cite examples included in Annexes II and/or IV of CD 92/43/EEC such as Cerambyx cerdo, Euphydryas aurinia, Geomalacus maculosus or Lucanus cervus.
However, at a faunal level, the importance of the Cíes Archipelago lies mainly in the presence of important migratory bird colonies, such as the wintering population of the Yellow-legged Gull (Larus cachinnans), which accounts for 95% of the total population counted in winter in the Spanish state, being considered one of the largest European colonies of this species. Also highlighting the populations of European shag (Phalacrocorax aristotelis) and common turnstone (Arenaria interpres). Also considered of great importance in the Cantabrian-Atlantic Spanish context are the populations of the European storm-petrel (Hydrobates pelagicus) and the black-backed gull (Larus fuscus), as well as the common guillemot (Uria aalge).