Characteristics of Mangrove Plants
Stabilization of mud-flats is a preliminary process in the establishment of mangroves. Pioneer plant species like Porterasia coarctata and Cyprus spp. initiate this process. The roots of these plants help in binding the soil and also help the establishment of micro-organisms which further help in stabilizing the area. Stabilization starts from the land side and gradually shifts towards the sea. These pioneer plants are slowly replaced by other mangrove plants and then mangroves gradually spread towards the sea. Once mangroves grow, the submerged banks are fully stabilized; after this, mangroves slowly reach climax vegetation stage. Climax vegetation is represented by the complete circle of life where there are different species of plants, animals (both terrestrial and aquatic) and micro-organisms forming an ecosystem called the tropical salt marsh or the mangrove ecosystem. In case the sediments are not stabilized, submerged banks are washed out. Like in Gangetic delta, thousands of deltas are formed and washed out every year before they can be stabilized.
(a)Specialized Root System in Mangroves-
The major plant species forming the mangrove ecosystem have aerial roots, commonly prop roots or even stilt roots. Stilt roots serve to anchor the plants, but also are important in aeration, because the mangrove mud tends to be anaerobic. Rhizophora spp. (Red mangroves) have prop roots descending from the trunk and branches, providing a stable support system. Other species, including the white mangroves (A. marina) obtain stability with an extensive system of shallow, underground ”cable roots” that radiate out from the central trunk for a considerable distance in all directions: pneumatophores extend from these cable roots.