Located on the southern slopes of central Alborz mountains adjacent to Tehran. This 26907 ha area has been protected since 1982. The altitude range of 1700-3900 m and mean annual precipitation and temperature of 700mm and 5 C, respectively have resulted in warm Mediterranean and temperate sub-humid climates. The exceptionally high animal and plant biodiversity of the area is a characteristic feature of the region. 577 plant and 162 animal species have been identified in varjin. Some of the main plant species are juniper,willow, ash tree, almond, oxytropis, thyme, rhubarb, mullein, borage, prickly thrift and different species of gramineae. The main animal species of the region include alborz red sheep, wild goat, leopard, wild boar, hyena, chukar partridge, Caspian snowcock, tawny eagle, transcaucasian meadow viper, Latifi’s viper, brook trout and lenkoran. The region plays an important role as a corridor for the animals-especially wild sheep wild sheep-between central Alborz and Lar national park. Interesting habitat characteristics and high biodiversity of the region have provided researches with a natural laboratory. Numerous springs, diverse vegetation cover, novel landscapes and adjacency with Tehran, have resulted in the attraction of tourists far more that what t he area can sustain. This has resulted in high pollution of the Jajrud river, considerable land use conversion and uncontrolled construction and population growth in the rigion.