One of the most ambitious objectives of Directive 92/43/EEC is the creation of a coherent ecological network, the Natura 2000 Network, made up of places declared in accordance with Directive 79/409/EEC, as Special Protection Areas for Birds SPA, as well as those designated for the conservation of habitats in Annex I and wild flora and fauna species in Annex II of Directive 92/43/EEC itself, designated in its phase initially as Places of Sites of Community Importance SCI, and in its final phase as Special Conservation Area SAC.

The designation of a territory as SPA is carried out after evaluating the importance of the place for the conservation of bird habitats (article 4 of Directive 79/409/EEC), included in Annex I of the Birds Directive, and It consists of only one stage. This implies that the places designated as SPA are directly integrated into the Natura 2000 network.

Regarding the designation of the SCI and SPA, article 4 of Directive 92/43/EEC lays out a protocol that includes three stages.

The first stage consisted of drawing up a list of places in order to be designated as Sites of Community Importance (SCI), carried out in accordance with the technical requirements established in Annex III of CD 92/43/EEC, and from of the scientific-technical information available in each territory. For each of the Biogeographic Regions, a set of specific areas are proposed, designated as pSCI (pSCI = proposed Site of Community Importance) that encompass types of natural habitats listed in Annex I of CD 92/43/EEC, and types of habitats of autochthonous species of flora and fauna, listed in Annex II of the aforementioned regulations.

This initial proposal for Sites of Community Importance (SCIs) was submitted for evaluation by the technical teams of the Directorate General for the Environment of the European Commission, requesting additional information on the proposed spaces, as well as formulating the need to increase the existing ones or create new spaces, with in order to guarantee compliance with the objectives established by CD 92/43/EEC.

In the second stage, the European Union approves the different lists of Sites of Community Importance in common agreement with the Member States. This phase began in 2002, with the listing of the Macaronesian Biogeographic Region, and continued with that of the Atlantic Biogeographic Region in 2004 (Commission Decision of 12/7/2004. OJEU, 12/29/2004) and finally the Mediterranean Biogeographical Region in 2006 (Commission Decision of 07/19/2006. OJEU 9/21/2006).

According to data provided by the General Directorate for the Environment of the European Commission at the end of 2021, the Natura 2000 Network is made up of more than 27,000 places, occupying more than 1 million km2 that represent 18% of the earth's surface and 4% of the marine area of ​​the European Union (EUR27). Including 3,372 SPAs, with an area of ​​823,362 km2, being represented in 894 marine SPAs, which represent an area of ​​298,324 km2. As for the SCIs/SACs, their number amounts to 23,659, covering an area of ​​940,510 km2, with marine environments represented in 2,027 SCIs, covering an area of ​​350,570 km2.

The third stage, established in article 4.2 of DC 92/43/CEE, consists of the designation of Sites of Community Importance (SCIs) as Special Areas of Conservation (SACs). Article 1, letter l, of the Directive defines a SAC as a Site of Community Importance (SCI) designated by the Member States through a regulatory, administrative and/or contractual act, in which the necessary conservation measures are applied for its maintenance. the re-establishment, in a favorable state of conservation, of the natural habitats and/or of wool populations of wool species for which the site has been designated”.

Article 4.4 of the Habitat Directive provides that, once a Site of Community Importance has been chosen in accordance with the procedure regulated in section 2 of this same provision, the Member State in question will designate said site as a SAC as much as possible. quickly as possible and within a maximum period of six years, setting priorities according to the importance of the sites, for the maintenance or restoration, in a favourable state of conservation, of a type of natural habitat listed in Annex I or of a species of those of Annex II and for the coherence of Natura 2000, as well as depending on the threats of deterioration and destruction that weigh on them.