Forming a natural barrier between the Mediterranean Basin and the dry plateaus of Western Asia, the mountains and basins that make up the Irano-Anatolian Hotspot contain many centers of local endemism. Nearly 400 plant species are found only along the Anatolian Diagonal, a floristic line that crosses Inner Anatolia; many of Turkey’s 1,200 endemic species occur only to the immediate east or west of it. The hotspot includes four endemic and threatened species of viper.

The topographically complex and extensive system of mountains and closed basins that make up the Irano-Anatolian Hotspot form a natural barrier between the ecosystems and indigenous cultures of the Mediterranean Basin and the dry plateaus of Western Asia. For many centuries, the Silk Road crossed east to west through this hotspot, connecting the two regions. The hotspot covers 899,773 km², including major parts of central and eastern Turkey, a small part of southern Georgia, the Nahçevan Province of Azerbaijan, much of Armenia, northeastern Iraq, northern and western Iran, and the Northern Kopet Dagh Range in Turkmenistan.

Elevations in the Irano-Anatolian Hotspot range from as low as 300 meters, in the foothills of the Kopet Dagh and western Zagros Mountains, to more than 5,000 meters, including the dormant volcanoes of Mt. Ararat in Turkey (5,165 meters) and Mt. Damavand in Iran (5,671 meters). The plateaus of Anatolia, Armenia, and western Iran range between 800 and 2,000 meters. Historically, the mountains have served as both a refuge and a corridor between the eastern Mediterranean and western Asia, resulting in many patches of local endemism throughout the region.

The climate is continental, with hot summers and very cold winters. Annual rainfall varies from 100 to over 1,000 millimeters, most of it falling in winter and spring. The principal habitat in the hotspot is mountainous forest steppe, supporting oak-dominant (Quercus spp.) deciduous forests in the west and south (Anatolia and Zagros mountains) and juniper (Juniperus spp.) forests in the east (southern slopes of the Elburz mountains and the Kopet Dagh). A wide zone of subalpine and alpine vegetation covers the mountain peaks above the timberline, and thorn-cushion formations are found in the subalpine zone. There are permanent glaciers in the alpine zone of Turkey’s Cilo and Hakkâri mountains.