Sunderbans lost 2% mangrove cover in two years, reports central survey
The Sunderbans, the world’s largest mangrove delta and home to the Royal Bengal Tiger, has lost nearly two percent mangrove cover in the last two years, according to the state of forest report 2019.
Released on Monday in Delhi, the Forest Survey of India (FSI) report, said the mangrove cover in the Sunderbans has shrunk by more than two square kilometres – from 2214 sq km to 2112.11 sq km - between 2017 and 2019.
Experts pointed out that the Sunderbans have been shrinking over the past few years and warned of its disastrous effect for both Kolkata and the livelihood of local villagers if the trend continued.
“The Sunderbans’ thick mangrove growth acts as a bio-shield and saves Kolkata from the direct onslaught of cyclones that originate over the Bay of Bengal. The mangrove also acts as a spawning ground for fishes and other aquatic animals such as crabs and prawns on which local people depend for their livelihood,” said Tuhin Ghosh, director of the School of Oceanographic Studies at Jadavpur University.
The FSI report, however, has said that it is the “very dense mangrove cover,” which comprise pristine and thick mangrove, that has suffered maximum loss. The delta has lost nearly three square kilometres of this very dense mangrove cover, from 999 sq km in 2017 it is come down to 996 sq km in 2019.
The open mangrove cover, which comprises mostly new plantation, has increased by around one square kilometre, while the moderately dense mangrove cover has remained unchanged during these two years.
“Usually the State of Forest Report is prepared by collecting satellite data and followed by ground-level verification. But in the Sunderbans, ground verification in every part is not possible. This could create an error margin of nearly 5%. Erosion could be one of the major reasons behind this loss. But unless we compare the maps of the last few years it would be difficult to say exactly where the mangrove has shrunk and why,” said Ravi Kant Sinha, chief wildlife warden of West Bengal.
The Sunderbans spreads over 10,000 sq km across India and Bangladesh, of which 40% lies in India, and is home to many rare and globally threatened wildlife species such as the Royal Bengal Tiger and the estuarine crocodile. In India it is confined to the southern tip of West Bengal and spreads over two districts – South 24 Parganas and North 24 Parganas.
Pointing to previous reports of FSI, experts said that the Sunderbans had been shrinking because of human onslaught, widening of rivers and rising water level in the Bay of Bengal.
The very dense mangrove cover, which actually acts as the barrier against cyclones storms, has come down from 1038 sq km in 2011 to 999 sq km in 2017. The moderately dense forest cover has also shrunk from 881 sqkm to 692 sqkm. It is only the open mangrove that has increased.
“Human onslaught is rampant. Mangroves are being cleared for timber, infrastructure development, construction of hotels and resorts, farming and aquaculture. The mangrove cover has been going down over the past few years. It is only recently that the National Green Tribunal and local courts have intervened because of which such activities have come down,” said Pranabesh Sanyal, former chief wildlife warden and former chief environment officer of West Bengal.