Mangrove forests are unique wetland ecosystems that are established directly in theintertidal zone. Mangrove forests of southern Iran mainly consist of Avicennia marina, aspecies that was named after the great Iranian scientist, Avicennia (or Abu-Ali Sina). The Harra forestconstitutes the most western limits of the mangrove forests of south-east Asia. Harra Protected Areais located in the Khuran Straits, between Qeshm Island and mainland (Khamir Port), consisting ofmangrove forests that have grown more or less densely in the wet and muddy areas of this intertidalwetland. Daily tidal change is the main determining factor in forming the Harra ecosystem. Althoughthe Harra forest is quite homogenous in its composition, with low diversity of plant species, it ishome to a very diverse fauna. This Protected Area is also on the list of Internationally ImportantWetlands (Ramsar Convention).
The Harra forest is a mangrove forest that is only found in coastal areas in tropical regions. Athigh tide, the tree coverage may only be seen above the water level (salt water), while the rest ofthe tree parts are underneath the water. Only at low tide, one can see the trunk and aerial roots ofmangroves. Mangrove forests can easily grow in salt water. Mangroves may have been floweringplants that were pushed to their limits due to lack of capacity in competing with other terrestrialplants. They have then adapted to the difficult conditions of the intertidal zone, which has formedthis unique ecosystem.
High and low-tide have been critical in shaping the mangrove forests and its related biodiversity.Mangrove forests host a variety of water birds,which, at low tide feed on the muddy intertidalzone. In fact, each bird species is well adaptedto feed on very specific organisms that live atcertain depths in salt water or the mud.
In general mangroves can’t use sea water,because the salt that enters the plant throughthe sea water, after evaporation of water fromthe surface of the leaf , will form a salt solutionin the leafs. To address this issue, the rootsof mangroves act as a goal-oriented filter, andallow distilled water to pass through them,preventing the salt to enter. Only minimallevels of salt that are necessary for normal cellfunctions may enter the plant and get stockedin the leaf cells. Leafs with too much salt fall,and in this way, the salt is eliminated. Anothermechanism to eliminate the salt is the glandsthat are located underneath the leafs.