Mangroves in Lagoon Ecosystems - A Neglected Habitat in Sri Lanka

Abstract

Mangroves are limited to the coastal ecosystem and are associated with lagoons and estuaries due to high salinity, low oxygen levels, high light intensity, strong winds and periodic inundation by tidal water. Many lagoons, out of 82 lagoons in Sri Lanka, mangroves play an important role on microscopic and mesoscopic fauna and also for coastal inhabitants in the country. The micro relief of the mangrove habitats produces food and shelter, and provides nursery grounds for the birds, fish, reptiles and other crustaceans. Further, they help to preserve the balance of nature. Different research groups viz., individual scientists and institutional researches provide different figures on the extension of mangrove vegetation in Sri Lanka. However, there is no conformity on total figure. In this study, we try to calculate the exact extent of mangrove vegetation in 82 lagoons with their availability and identified threats. Mangroves in the lagoons of Sri Lanka have been damaged by anthropogenic activities and have also been degraded by (a) changes in freshwater run-off, salinity regime and tidal flow patterns; (b) excessive siltation and discharge of toxic substances; and (c) flowing of polluted water into lagoons, lakes, estuaries and tidal creeks. The depletion and degradation of mangroves have directly and indirectly influence the livelihood of the people, economy of the country and survival of the wildlife. Therefore, an increased public awareness is of utmost importance to promote management and conservation of mangrove habitats for posterity in Sri Lanka.