May 06, 2010 (LBO) – Sri Lanka’s coastal lagoons could be threatened by rapid sedimentation as a side-effect of fresh mangroves planted by humans for protection against a possible future tsunami, a researcher has warned. “However this activity ranked highest among investments made both by government and non-governmental organizations,” Samarakoon told a forum organized by the International Conservation Union (IUCN), an environmental charity, in Colombo.
“The adverse impact on sedimentation is now becoming visible.”
He says in Indonesia, Malaysia and Bangladesh, mangroves that grew along the coast facing the sea especially in shorefront deltas had absorbed the energy of tsunami waves and protected settlements in their shadow.
“Mangroves of this type do not exist in Sri Lanka along the tsunami affected coastline,” Samarakoon said.
“Therefore by ‘false analogy’, justification was provided for planting mangroves inside barrier-built estuaries.”
Because mangroves grow inside such estuaries they are also believed to help fish stocks but he says the role of other factors including sea grass and unpolluted water may have been ignored and a causal relationship may have been assumed without sufficient stud