Mangrove cover across Raigad, Ratnagiri and Sindhudurg districts witnessed a 30% net increase this year but a 4% decline was recorded in districts of Palghar and Thane in the Mumbai Metropolitan Region (MMR).

Raigad recorded a 33% rise in mangrove cover with highest increase across all districts at 35 sq. km. This takes its mangrove cover tally to 141.21 sq. km as compared to the India State of Forest Report (ISFR) 2017 prepared by the Forest Survey of India (FSI) that recorded 106 sq.km.

The increase was revealed in a 2018 assessment of mangrove cover across coastal districts of Maharashtra by the Central Institute of Brackishwater Aquaculture (CIBA) under the Indian Council of Agricultural Research (ICAR) submitted to the state mangrove cell last week.

While Ratnagiri recorded a 25% rise from 30 sq. km in 2017 to 37.58 sq. km in 2018, Sindhudurg recorded 13.71 sq. km this year against 12 sq. km last year, a 14% rise in mangrove cover. At Palghar and Thane, the area of mangrove forests fell from 90 sq. km to 86.23 sq. km. Mangrove cover in Mumbai city and suburban areas was not studied.

The mangrove cell said focus on livelihood activities helped boost mangrove cover across three districts and humanactivities led to decline in remaining districts. “There is better awareness about the legal protection given to mangroves. Efforts by the mangrove cell to spread this awareness led to coastal communities being sensitised and consciously safeguarding these trees. The enforcement machinery is also much stronger than five years ago, and sapling plantation drives have been regularly carried out,” said N Vasudevan, additional principal chief conservator of forest, state mangrove cell.

Environmentalists had mixed views about the report. “A 33% increase over a span of a year is impossible at Raigad district because maximum number of mangrove destruction cases have happened in Uran, Navi Mumbai, and surrounding mangrove forests. The mangrove cell needs to make the report public to validate the findings,” said Debi Goenka, executive trustee, Conservation Action Trust. Goenka was also the petitioner in the Bombay high court (HC) whose public interest litigation led a to landmark order in September this year to declare all mangrove areas as protected or reserved forest.

Others confirmed the findings based on plantation activity carried out by the state government and excess siltation along the Konkan coastline. “The mangrove cell has consciously carried out a lot of mangrove plantation activity, and the survival rate has been good. However, due to reclamation activity towards the north Konkan region including Mumbai, Thane, Palghar and parts of Raigad district, the mangrove seedlings are moving south along with the tide and being deposited in previously unknown areas and due to excess siltation, the trees are thriving,” said Stalin D, director, non-governmental organisation (NGO) Vanashakti and member of the state mangroves committee.

“Siltation does play a role but it has always been happening and is a regular process. But if that was the main reason then mangrove cover would not have stagnated between the years 2000 and 2005, and witnessed a rise thereafter,” said Vasudevan.

The total mangrove forest area including mangroves on private land increased from 222 sq. km in 2015 to 304 sq. km last year, according to ISFR 2017. Of this, 151 sq. km has been identified as reserved forest with final notification still pending. The mangrove cell estimates that following a landmark order by the HC from September this year, another 20 sq. km will be gain protection as reserved forests.

“The inquiry report from some of the coastal districts is yet to be submitted. However, after the HC order, mangrove areas under the jurisdiction of agencies such as the City and Industrial Development Corporation (Cidco), Jawaharlal Nehru Port Trust (JNPT), and the Mumbai Metropolitan Region Development Authority (MMRDA) are all to be declared as reserved forest. The final notification will be carried out notifying all these sites for enhanced protection,” said Virendra Tiwari, additional principal chief conservator of forests (Mantralaya), Maharashtra forest department.

Independent scientists said the methodology of such studies plays a pivotal role in identifying total mangrove cover. “Even though all research agencies use the same scale to generate maps, the resolution of satellite studies are different. In this case, CIBA used higher resolution satellite imagery that identifies more area of mangrove forests as compared to resolution used by FSI in their studies focused canopy distribution. There might be an increase due to natural or man-made factors but due to difference in data analysis, the results might differ,” said a senior scientist who has carried out mangrove research along the Konkan coast from the National Institute of Oceanography, Goa.

First Published: Nov 26, 2018 00:57 IST