The Transcaucasian Highlands

The Transcaucasian Highlands are among the most interesting areas in the World from a botanical point of view. The high diversity in flora and vegetation types has attracted the attention of botanists for more than 200 years. In this chapter we analyze this richness, show the diversity of ecosystems in this region, and the peculiarities of its flora with special attention to endemism in plant genera and species. A short section is devoted to the main threats to plant diversity in this area. The Transcaucasian Highlands are located on the border of the Euro-Siberian and the Irano-Turanian biogeographical regions and at the junction of the Caucasian and Irano-Anatolian biodiversity hotspots. More than 4000 vascular plant species occur in the Transcaucasian Highlands of which around 10% are endemic to this region. The lower mountain belt (375–1200 m a.s.l.) is covered by semi-deserts of gypsophilous or halophilous vegetation types. There are salt marsh areas as well as the Transcaucasian sand desert. The middle and upper mountain belts (1200–2200 m a.s.l.) are characterized by various kinds of steppe and forest vegetation, meadow-steppes, shrub steppes and thorn-cushion (tragacanth) vegetation. The altitudinal span of the forest belt varies from 500 to 2000 m a.s.l. depending on the region, and may approach 2400 m a.s.l. when open park-like tree stands are included. The subalpine and alpine belts (2000–4000 m a.s.l.) are covered by tall-grass vegetation, meadows and carpet vegetation.