Comments on "Coastal mangrove forests mitigated tsunami" by K. Kathiresan and N. Rajendran [Estuar. Coast. Shelf Sci. 65 (2005) 601-606]

Abstract

In a paper published recently in the journal Estuarine, Coastal and Shelf Science, Kathiresan and Rajendran (2005) present a "case study on the mitigating effect of mangroves on human lives against tsunami." They use simple linear regressions to identify factors responsible for differences in per-capita mortality between 18 coastal hamlets in Tamil Nadu, India in the wake of the Boxing Day Tsunami of 2004. They find that mortality is significantly associated with hamlet elevation, distance from sea and the area of coastal frontage given to vegetation. From these analyses, they primarily conclude that "human habitation should be encouraged...behind dense mangroves and or other coastal vegetation." This is a potentially important finding and, if true, could save many lives in future. However, we have found several fundamental errors in their statistical analysis that undermine their main conclusion. We discuss these issues below.