Spatial and temporal changes in mangrove cover across the protected and unprotected forests of India

Mangroves are vulnerable to natural environmental changes and anthropogenic disturbances; but, the status and change dynamics at a national level are poorly understood. Consequently, this research is aimed to assess the changes in major mangrove forests of India between the period of 1989 and 2013, covering an area of 62678 km2 from five coastal states. Landsat satellite data, post-classification approach, and ground truth verification were used for the mapping of the mangroves and assessing the changes in protected and unprotected forest regions. Our findings revealed that mangrove extent has increased from 3006 km2 to 3406 km2 within the period of study. Of the mangrove extent, 91% in 1989 and 80% in 2013 were located in the protected forest regions. The annual average rate of increase in mangrove area was 0.55%/yr. The mangroves gained and lost were 918 km2 and 517 km2 respectively, of which 53% of the growth and 81% of the loss occurred in protected regions. Natural factors were responsible for 97% of gain and 92% of the loss of mangrove area. The anthropogenic drivers were responsible for the 8% of mangrove conversion. The extent of mangroves grown was greater than that of deforestation in India, unlike many other shrimp growing countries. The results of the present study indicate the areas of intense change in mangrove forests and also provide important insight into the supportive efforts of mangrove conservation.