AT a time when Chennai is flooding which indicates the importance of mangrove covers, Maharashtra has reported the highest rise in mangrove cover across the country in the past two years, according to data from Forest Survey of India (FSI). Mumbai has seen a five square kilometer rise in its mangrove cover from 43 to 48 and Thane has noted a six sq km rise.
Mangroves can make an impact in deterring cyclones, tsunamis and strong winds. However, it does not have a direct impact on diluting the effect of floods. According to FSI data, the mangrove cover in the state had remained constant at 186 sq km since 2005 till 2013. Then a sudden jump to 222 sq km was registered this year. “It is because of the constant efforts to preserve the mangroves in the state,” said Kalyan Kumar, Secretary of Indian Forest Survey Association, Maharashtra.
He added that the process of mapping mangrove cover involved periodic analysis of vegetation through satellite imagery and then comparing it with previous vegetation.
Environmentalists, however, blamed inaccurate results of satellite mapping for the constant figure all these years.
While there has been an overall rise in the state, the island city has a poor open mangrove cover at two sq km. The suburbs fare better with 48 sq km mangrove cover. The highest increase in the state has been noted in Raigarh district. A 24 per cent rise in mangrove cover was recorded in Raigarh compared to a 12 per cent rise in Mumbai.
According to environmentalist Debi Goenka, mangroves act as a physical shield during natural disasters. “They have high water absorbing capacity,” he said. He, however, claimed that land lost due to the state government’s nod to Navi Mumbai airport would cost at least 400 acre of mangrove cover. “There might be an increase in cover in certain areas, but there are other areas where mangroves are slowly depleting. The Navi Mumbai airport will be developed in a low lying area where 250-acre forest will be wiped off,” he added.
Environmentalist Rishi Agarwal also said that the methodology of the survey needed to be first discussed to understand its accuracy. “We receive complaints of mangrove destruction every day. Dahisar West, Malad, Mira Bhayander and Vassai-Virar stretch face constant threat of mangrove destruction. If the report claims a rise, it should be visible on the ground,” he said. He added that he had noted a rise in magrove cover in Thane creek due to constant siltation.
The total mangrove cover in India is 4,740 sq km. After Maharashtra, Odisha has reported the highest rise in mangrove cover by 18 sq km. In Mumbai, while there are no dense mangroves, open mangroves constitute 26 sq km of total area.