Patterns, distribution, ecological features, and conservation issues of endemic plants in Armenia

This study aims to analyse plant endemism in Armenia. The richness of the republic’s flora was assessed in terms of the representation of endemic taxa. The distribution of endemic plant species was identified and analysed both within the republic and across altitudinal belts and major ecosystems. The greatest number of endemic taxa belongs to the families Rosaceae, Asteraceae, Fabaceae, and Poaceae, with the richest genera being Pyrus , Astra­galus , and Psephellus . Most endemic species are confined to the arid regions of the republic, particularly the middle mountain belt and grassy ecosystems. Several “centres of endemism” were identified, where populations of multiple endemic species coexist in a small area. The relevant government organisations must prioritise these centres when creating new protected natural areas. We identified 139 endemic taxa (species and/or subspecies) of vascular plants belonging to 27 families and 69 genera in modern Armenia. For Armenia, we calculated Bykov’s index (le = Ef/En, where Ef represents the real percentage of endemic taxa, and En denotes the expected or normal percentage of endemic taxa in the basic graph) to be 3.7, which is 3.7 times higher than the norm. This index surpasses that of renowned countries such as South Africa (3.6), Greece (2.1), Turkey, Cyprus (~2), and the Caucasus as a whole (1.3). This finding suggests that Armenia is one of the most significant territories in terms of plant diversity within the global biodiversity hotspot of the Caucasus. The greatest number of endemics belongs to the Rosaceae family, particularly due to a high diversity within the genus Pyrus (10 species), followed by the Asteraceae, Fabaceae, and Poaceae families. The Caryophyllaceae (10 species) and Scrophulariaceae (eight species) families follow. At the genus level, Pyrus has 10 local endemic species, while the largest genus in Armenia, Astragalus , has seven endemic species, as does Psephellus , followed by Centaurea (six species). The highest number of endemic vascular plant taxa is found in the Yerevan and Darelegis floristic regions, with fewer in the Aparan, Shirak, and Meghri regions. The majority of these taxa thrive in the arid regions of the Armeno-Iranian province of the Ancient Mediterranean subkingdom. Most of these species should be classified as neoendemics, formed in arid conditions. In contrast, the majority of endemics associated with the “Caucasian root,” which flourish in the more humid conditions of the remaining floristic regions of Armenia, are likely paleoendemics, preserved from glacial and postglacial periods. The overwhelming majority of endemic vascular plant taxa in Armenia are confined to herbaceous habitats—84 species. Significantly fewer are found in petrophyte habitats and those with no or poorly developed vegetation—29 species, in forest and shrub habitats—25 species each, and in aquatic habitats, where only seven taxa are present. No endemic species or subspecies have been recorded in marsh habitats. This distribution can be attributed to the fact that herbaceous habitats occupy nearly two-thirds of Armenia’s territory. Furthermore, most endemics are associated with arid ecosystems, which are predominantly represented by habitats of this category.