Portugal has also failed to adopt "the necessary conservation measures that meet the ecological requirements of the natural habitat types listed in Annex I to the Habitats Directive and of the species listed in Annex II to that Directive present in those sites of Community importance".

The European Commission brought an action on 26 April 2018 for failure of Portugal to designate seven sites of Community importance (SCIs) for the Atlantic biogeographical region, recognised by Brussels in December 2004, and 54 others for the Mediterranean biogeographical region, recognised in 2006, as Special Areas of Conservation (SACs) as soon as possible and within six years.

The CJEU also said that the conservation measures adopted by Portugal, in particular the Natura 2000 Sectoral Plan, as well as others referred to by the Portuguese authorities, do not meet the specific ecological requirements of the natural habitat types and species listed in the Annexes to the Habitats Directive and cannot therefore be considered as 'necessary conservation measures'.

According to the Commission, the deadlines for designation expired on 7 December 2010 and 19 July 2012 respectively, and Portugal has not yet designated the sites of Community importance as Special Areas of Conservation.

The Habitats Directive imposes an obligation on Member States to contribute to the establishment of the Natura 2000 network according to the representation, on their respective territories, of those types of natural 'habitats' and species 'habitats' and to designate sites such as SACs for that purpose.

The procedure for designating sites as SACs takes place in four stages. Once a site of Community importance has been recognised by the Commission, the country will designate it as an SAC as soon as possible and no later than six years after the Commission's decision in question.