The site comprises the Kalibar Mountains, to the south of the Aras river in northern Azarbayjan c.90 km north-east of Tabriz. It extends from the semi-arid steppic foothills at c.1,500 m in the south, over the mountain tops at c.2,500 m, and down into the valley of the Aras river (in the Caspian drainage basin) at c.700 m in the north. The relatively dry, southern slopes are covered with steppic vegetation. The northern slopes are deeply dissected into parallel ridges and steep-sided valleys. Moisture-laden winds from the Caspian support deciduous forest up to c.2,000 m, and lush alpine meadows above the tree-line. There are numerous perennial springs and streams draining north into the Aras river. This rather isolated patch of deciduous forest forms an outlier of the extensive forests of the Caucasus to the north. Summers are generally warm and pleasant, but winters are extremely cold with heavy snow. There are many small villages, but access has remained difficult because of the absence of all-weather roads. The wide range of habitats in the Protected Area includes Artemisia steppe and wheat cultivation on southern slopes, alpine tundra on the rocky summits, alpine meadows above the tree-line, and deciduous forest and scrub dominated by Quercus and Rosa on the northern slopes. Large areas of forest have been cleared for the cultivation of cereals and vegetables and for orchards and pastureland, and much of the remaining forest has been degraded by grazing and cutting of fuelwood. Land ownership is public.
See box for key species. This is Iran's only locality for Tetrao mlokosiewiczi, which is restricted to the upper deciduous forest and alpine meadow zones in the south-central part of the reserve at 1,800–2,100 m. This population was discovered in 1971, and was estimated to number 200-300 birds, but there has since been some decline due to forest clearance in the early 1970s. By 1977, the grouse were confined to two areas (Dogorun valley and an area north of Kharil), and the population was thought to be only c.110 birds. The reserve supports a diverse forest and montane avifauna, including a number of species with very restricted breeding ranges in Iran, such as Turdus philomelos, T. merula, Locustella naevia, Acrocephalus palustris, Sylvia curruca, Saxicola rubetra, Parus caeruleus, Pyrrhula pyrrhula, Serinus pusillus and Emberiza hortulana. Phylloscopus trochiloides nitidus is particularly common in the forest. Aquila chrysaetos is resident. At least 104 species have been recorded in the reserve.
Non-bird biodiversity: Mammals: unusually high densities of Ursus arctos (rare) and Canis lupus (V), as well as populations of Lynx lynx (rare), Ovis ammon (rare) and Capra hircus (rare).
BirdLife International (2019) Important Bird Areas factsheet: Arasbaran Protected Area. Downloaded from http://www.birdlife.org on 17/02/2019.