Kerala Mangroves' Pastures of Estuaries - Their Present Status and Challenges

Mangroves form most valuable biomass and act as a living buffer/ bioshield/ biowall preventing coastal erosion and damage to infrastructure and loss of life by reducing the destructive force of nature. Mangroves are the most carbon rich forest in the tropics and soils are high in carbon. In the tropics, along the coastline mangroves live where many people want to live and hence the amount of land they grow on has declined by 30 to 50 % over the past 50 years. In most forests, sediment and litter decay rather quickly, but in mangrove forest there is not enough oxygen to break down the litter so the breakdown of material is much slower and this means more CO2 storage. Daniel Donato (US Agriculture Department) reported that tropical mangroves are better at storing CO2 from atmosphere two to four times more than tropical rain forest store and its storage is mostly on that thick organic muck layer in the soil. In India, mangroves account for about 5 percent of the world's mangrove vegetation and are spread over an area of about 4, 500 km2 along the coastal States. Mangroves are highly localized in Kerala, but the species diversity and their associates are comparatively rich. Mangroves are confined to estuaries, lagoons, backwaters and creeks. In Kerala mangroves are distributed in all districts except Idukki, Pathanamthitta, Palakkad and Wayanad and the maximum extent is reported from Kannur district (1100 ha. ), Ernakulam (600 ha. ) and Kasaragod (315 ha. ) and the minimum extend was represented by three districts, Malappuram (26 ha. ), Thiruvanthapuram (28 ha. ) and Thrissur (30 ha. ) (Vidyasagaran and Madhusoodaran, 2014). During the survey, a total of 24 pure mangroves were recorded belonging to 15 genera and 9 families. Rhizophoraceae represented by 8 species, Acanthaceae 4 species, 1 species each representing Myrsinaceae (Primulaceae), Malvaceae, Combretaceae and Pteridaceae, two species from Euphorbiacea, three each from families Lythraceae and Arecaceae. Present survey revealed that Lumnitzera racemosa, Nypa fruticans, Phoenix sylvestris, Phoenix humilis var. pedunculata and Ceriops tagal are the most threatened species in the west coast of India, similarly Bruguiera sexangula is also confined in few places wherein their populations is facing further decline. Unmindful of the vital role they have in maintaining aquatic as well as avian fauna, mangroves are being destroyed at an alarming rate in India. For instance, mangrove forests that once adorned Kerala's entire coastal area are now reduced to just 17 sq km, of which only 2 sq km comes under the government. The Kerala Forest Ministry identifies human encroachment as the major reason for depletion of mangrove. The popular misconception that plant species in mangrove forests are of no use has added to its slow death. Mangroves of Kerala are considered as the relics of the past. Land reclamation, industrialization and invasion made extensive clearing and degradation of many areas. Hence there is an urgent need to protect the remaining mangrove areas and a massive afforestation campaign is to be initiated with the full hearted support of the local governess.