Vegetation characteristics of four ecological zones of Iran

Environmental (topography, climate) features have an important influence on plant diversity and richness of Iran. On the basis of environmental factors, four ecological zones with specific plant richness from lowest area to highest area (Hyrcanian, Khalij-o-Omani, Zagross and Iran-o-Touranian zones) were established respectively. Topography is from –28m which is close to Caspian Sea to 5678m which is located on the Alborz Mountain. Two mountains (Alborz and Zagross) prevent moist air moving to the centre of Iran. Northern Iran is rich in biodiversity with 8000 plant species representative of many different life forms (Herb, Grass, Shrub and tree) in the Hyrcanian zone that is located north of. 35oN latitude. In contrast, the lowest plant diversity is in the southern part of Iran (Khalij-o-Omanian zone), which is a flat area. The vast central plateau (Iran-o-Touranian) is divided into two divisions with mountain part and an area of high plains. The western part of Iran (Zagross zone) is affected by Mediterranean and Black sea moisture which brings snow in the winter. The dominant species are low growing plant species with forbs, grass, shrub and tree life forms. Topography and climate factors interact to plant influence distribution and richness of Iran and they play an important role in creating microniches that foster great ecological biodiversity of this country.