After analysing more than 750 Landsat satellite images, researchers came to the conclusion that the actual reason behind the depletion of mangrove forests is agricultural expansion, and not shrimp farming in the region.
The study involved quantifying the rates and causes of change from 1975 to 2005 and identifying the deforestation 'hot spots'.
The researchers found that the major factors responsible for mangrove deforestation in the study area included agriculture encroachment (81 percent), aquaculture (12 percent), and urban development (two percent).
Time-series analysis of historical data from the Landsat archive also suggested that the tsunami-impacted region lost 12 percent of the mangrove forests in the last three decades, much lower than the estimated mangrove loss in Asia, which ranged from 25 to 50 percent.
According to the researchers, mangrove loss varied from country to country and was also time specific.
The study found that the annual rate of deforestation was highest in Burma (- 1 percent) and lowest in Sri Lanka (0.1 percent) from 1975 to 2005.
In contrast, mangrove forests in India and Bangladesh remained unchanged or gained a small percentage during the period, the study revealed.
The researchers said the data and information generated from this study could be used to identify potential rehabilitation sites, set conservation priorities, and quantify the role of mangrove forests in saving lives and property from natural disasters such as the December 26, 2004 tsunami.
The study appears in the Journal of Biogeography.