On the Prospects of In Situ Conservation of Medicinal- and Aromatic-Plant Genetic Resources at Ancient-Hillfort Sites: A Case Study from Lithuania

Twenty-three ancient-hillfort sites were investigated to evaluate the potential for the in situ conservation of medicinal- and aromatic-plant populations. An evaluation of the site’s suitability was carried out by employing three major groups of criteria: species-specific, site-specific, and threat assessment. The species-specific criteria included the total species number, target species number, the cover-abundance of the target species estimated by mean Braun–Blanquet score, and, as an additional criterion, the number and cover-abundance of crop wild relatives. The site-specific criteria included site evaluation with respect to climatic region, the area size of a site, the habitat type, and the site’s protection status. The threat assessment was focused on anthropogenic activities, such as recreational, agricultural, and others. The total number of vascular plant species inventoried was 264, including 82 species of medicinal and aromatic plants (MAP). There was a strong and highly significant correlation between the total and the MAP species numbers (r(s) = 0.77, p < 0.001), and the two most species-rich sites, Žuklijai and Pamiškė, contained the highest total and MAP species numbers. The investigated hillfort sites covered the populations of 49 species, or about 33% of the priority species list, with 5 or more populations. The most frequent species, Hypericum perforatum, occurred at 21 sites. The twenty-three hillfort sites represent three of the four climatic regions and six of the ten climatic subregions of Lithuania. Although these hillfort sites are quite small (1.24 ± 0.75 ha on average, without buffer zone), they are scattered across the country and are state-protected as archaeological objects, which makes them suitable for the in situ conservation of MAP genetic resources. In addition, seven hillfort sites (30.4% of the investigated ones) belong to the European network of special areas of conservation of habitats (Natura 2000), thus increasing their international importance. The threat assessment showed that anthropogenic activities (recreational, agricultural, etc.) are among the major factors affecting target-species populations.