in Sri Lanka - Ministry of Environment

Present Status of Mangroves in Sri LankaL.P.Jayatissa, University of Ruhuna, MataraMangroves are woody shrubs and trees that are salt and flood tolerant and hence dominateintertidal areas of lagoons, estuaries and sheltered bays along tropical and subtropicalcoastlines (Ball, 2002; Tomlinson, 1986; Tuffers et al., 2001). In the past, mangrove ecosystemswere considered as a marshy wastelands; then in the 1970s, as a valuable eco-system; andpresently, as precious but threatened eco-systems (Cormier Salem 1994).Being an island in the Indian ocean with more than hundred rivers starting from central highlandsand radiating towards the sea, Sri Lanka possess a large number of lagoons and estuariesalong its coastline of 1760km. As the coastline runs through different climatic zones anddifferent geomorphological settings, the diversity of mangrove habitats is remarkably higherand hence the species diversity in mangroves is also comparatively higher. The total numberof true mangrove species reported from Sri Lanka is almost one third of the global diversity oftrue mangroves in the world (Jayatissa et al., 2002). However, as the total annual range of tidalvariations is less than 1m, the mangrove coverage of the country is small. The present extentof mangroves in Sri Lanka has variously been estimated at over 4,000 ha (Arulchelvam 1968)to over 10,000 ha (Jayawardene 1968). Largest mangrove areas of the country are reportedfrom, north, north western and east coasts.Depending on the geomorphological setting of the habitat and the composition of commonspecies, De Silva, (1985) has recognized five kinds of mangroves in Sri Lanka: as riverinemangroves, fringing mangroves, basin mangroves, scrub mangroves, and over-washmangroves. However, the first two are the most common in Sri Lanka. Mangrove species arecommonly classified into two broad categories as follows;1. True mangroves (species restricted to mangrove habitats)2. Mangrove associates (not confined to the intertidal areas and occur in terrestrial vegetationalso)The list of true mangroves recorded from Sri Lanka is given in the Table with the abundance scale.(However the demarcation of mangroves and mangrove associates may be on tenterhooksbecause according to the literature these two categories vary and there are very suspiciouspoints and confusion. For this report, the categorization of species into true mangroves andmangrove associates are adopted from Tomlinson, 1986, except the genus Acrostichum). It isdifficult to give a clear limit for the list of mangrove associates as the composition of mangroveassociates could vary depending on the edaphic and climatic factors of the habitat. However,Acanthus ilicifolius, Acrostichum aureum, Clerodendron inerme, Hibiscus tiliaceus, Premnaintegrifolia, and Thespesia populnea are given as the most common mangrove associatesin Sri Lanka (Jayatissa et al., 2002). In mangrove forests, they may occur as a transitionalvegetation between true mangroves and the terrestrial vegetation. There is no any endemicspecies among true mangrove species or mangrove associates in Sri Lanka.197