Shoreline protection value and social dimensions of mangrove ecosystems in coastal villages affected by the' 2004 tsunami in Sri Lanka

Abstract

Sri Lanka is an island bordered by 1,562 km of coastline. The country encompasses a high diversity ofcoastal vegetation, specifically mangroves. These ecosystems have provided a wide array of goodsand services, ranging from fishery, forest products and tourism to shoreline protection. The protectivefunction of mangroves at the event of natural disasters, however, is hardly recognized. The need toassess the economic value of this function became more eminent to assist decision-makers and fundingagencies in integrating environmental rehabilitation in the tsunami reconstruction process.

The districts of Ham ban tot a and Tangalle are two of the largest coastal districts in southern Sri Lankathat experienced severe damage caused by the Indian Ocean tsunami. The disaster demonstrated thenatural protection afforded by coastal ecosystems. This study estimates the value of mangroveecosystems as shoreline buffer atthe event of extreme disasters. The availability of household damage cost information allowed the use of a comparative damage cost assessment approach to estimate thevalue of ecosystem conservation and wise management in mitigating natural disasters such as tsunamis.The methodology assessed the socioeconomic impacts of the tsunami disaster on 151 coastal householdsat two sites--Kapuhenwala and Waduruppa. The first site is characterized with well managed andfunctioning coastal ecosystems; and the latter exhibits a disturbed and degraded ecosystem.The assessment estimated a higher incidence of damage costs in areas with degraded mangrovevegetation. Results indicate that costs of damages to livelihood and property in Waduruppa (US$1,377,975) arc approximately ten times the costs of damages in Kapuhenwala (US$ 173,555). Thedamage costs avoided appraisal suggests that threatened mangroves reduce the protection affordedto inland properties, community infrastructures and livelihood by US$ 2,1 09/household. The estimateshows that areas with intact mangrove ecosystem generate greater economic benefits. The findingsalso indicate the economic rationale of including mangrove rehabilitation efforts in the post-tsunamireconstruction and rebuilding programs.