Towards the application of EU Habitats Directive to a non-EU country: the case of San Marino

• We focused on San Marino, a non-EU country enclaved in Italy. • We detected habitat types based on typical species and vegetation relevés. • The HD can promote the creation of an area-based conservation policy in San Marino. • We set a reference for non-EU microstates to adopt Habitats Directive criteria. In the European Union, biodiversity conservation is guided by the Birds Directive and the Habitats Directive, which provided the foundational policy for Natura 2000, the World’s largest coordinated network of protected areas. The Republic of San Marino, a European non-EU microstate enclaved within Italy, has ratified the UN Convention on Biological Diversity, but does not have a formalised area-based conservation strategy. In this study we test the adoption of the HD to the Republic of San Marino, by producing a formalised list of habitat types and a map of their distribution. We created a list of potential habitat types present in the country by extracting those located in a 10 km radius of the Italian land area surrounding San Marino. To verify their presence in the country, we actively surveyed vegetation plots in the period 2019–2022. We used non-metric multidimensional scaling to provide an ordination of the plots and analyse gradients in habitats at the country scale. We confirmed the presence of 9 habitat types and excluded 22 additional types. Despite the relatively small cover of confirmed habitat types (2.71 km 2 ; 4.4 % of the country territory), some of them are quite rare in the surrounding areas, highlighting the importance of local conservation measures and integration of the San Marino policy with Italian policies. The adoption of HD by non-EU states such as the Republic of San Marino could be a simple but valuable step to develop an area-based conservation strategy at the country level, aligned with the surrounding context.