Indigenous Plant Species from the Drylands of Iran, Distribution and Potential for Habitat Maintenance and Repair - Combating Desertification in Asia, Africa and the Middle East - page 345

Caspian sea

Hircanian

Iran-o-Touranian

Zagross

Khalidj-o-Ommanian

Persian Gulf

Fig. 17.3 Distribution of four ecological zones of Iran

2.1 Hircanian (Caspian) Zone

The region, extends throughout the south coast of Caspian Sea and northern part of
the country which is bordered by the largest lake in the world. Mountains dominate
the landscape of this ecoregion. Hircanian (Caspian) Zone could be divided into
three subdivisions on the basis of geographical situations(. ) These subdivisions are
(1) Alborz Range forest steppe, (2) Caspian Hircanian Mixed Forest and (3) Caspian
lowland desert.

Alborz range forest steppe: The highest peak in the Alborz Range is Mount
Damavand, a dormant volcano 5,766 m tall. Below Mount Damavand's crater are
two small glaciers, as well as fumaroles, hot springs, and mineral deposits. Only
between 280 and 500 mm of precipitation falls annually on this high elevations
of Alborz mountain. The dominant trees ( Juniperus sabina ,and J . communis )are
resistant to summer drought and heat and can tolerate winter cold equally well.
However, the trees grow so slowly that it is difficult to reestablish these forests
once they are cut. Shrubs include pistachio, Berberis integessima , Acer spp., and
Amigdalus spp., with Onobrychis cornuta , Astragalus gossipinus , Agropyron spp.,
Bromus Tomentellus forming the ground cover.
A network of large reservoirs supplies water to Iran's capital, Teheran, but
harnessing the water has severely disrupted aquatic ecosystems. Overgrazing at