Saving mangroves

Green Concern

Saving mangroves

The world’s only inland mangrove in the sacred grove of Kachchh, Gujarat, will degrade to extinction, unless the authorities concerned ensure the safety of the last eight trees in the area, writes Kalyan Ray.

They have stood tall for centuries, standing nature’s vagaries. But a sacred grove of mangroves in Gujarat now faces the threat of being wiped out from the face of the earth, unless immediate conservation measures are taken. Only the last eight trees remain.

The inland mangrove forest covering an area of less than a hectare near the Shravan Kavadia Temple in Bhuj (Kachchh district) is located on the fringe of the Banni grassland, in arid environment. As a nature’s wonder, its survival now is a matter of scientific study.

Even though the place is located more than 100 km away from the coast, the 0.7 hectares of mangrove population has survived. Such a mangrove system is not found anywhere else in the world. It has neither any connectivity with sea water, nor a supply of regular water for its trees.

What surveys say

The inland mangrove was identified as a temple forest, and nobody had caused any damage to the old trees there. When the first systematic count was undertaken two decades ago, there were 80 adult trees in a dense patch. Unfortunately, half of them were destroyed during the 1998 cyclone. The Forest Department reported the survival of 33 trees after the cyclone, which also included partially damaged ones. The Gujarat State Forest Department had partially fenced the area in 1998. In 2012, a group of scientists reported the existence of 18 trees in the inland mangrove area.

But earlier this year, when a team of researchers from the Gujarat Institute of Desert Ecology (GIDE), Bhuj, travelled to the Shravan Kavadia Temple, they spotted 16 trees, of which only eight were natural while the remaining ones were the coppiced branches of the original. The uprooted trees had strong trunks with a height of up to 18 metres and a diameter of up to 14 metres.

“The coppiced trees are not counted, as these are examples of vegetative propagation. There are only eight natural trees. We are not sure if the 2012 count of 16 trees suggest only the natural ones,” team leader Nimisha Tripathi from GIDE told Deccan Herald. “During our visits, we found several fallen logs of the old trees and few standing trees infested with wood-boring insects on the stems and branches with deteriorating tree growth. Further, absence of young saplings and seedlings at the site strongly indicated the complete elimination and extinction threat to this endemic inland mangrove species,” she recollected.

Sacred to a few 

The inland mangrove in Shravan Kavadia is one of the most sacred groves of Gujarat for the local inhabitants, and since long, fire, harvesting, logging or collection of firewood have been prohibited. They are considered religiously inauspicious by the locals for sustainable development of the area. The sacred grove of the mangrove species is located 80 km inland from the nearest coastal belt of the Gulf of Kachchh and 150 km from the Arabian Sea. The entire area is flat and without any gradient.

In natural state, the mangroves are dispersed for propagation (through seeds and propagules) by sea water. Hence the inland mangrove patches are of great geological interest. Over two millennia ago, the Rann of Kachchh was a shallow sea, which dried up with the uplifting of land due to tectonic shift. This led to the disconnection of mangroves from the sea and created a landlocked condition for them. The surviving mangrove patch in Shravan Kavadia belongs to one of the ancient biogenetic pools.

Kachchh represents one of the most fragile and peculiar desert arid ecosystems, where unique species of terrestrial and aquatic plants and animals exist. Kachchh is also a home to mangroves, which represent the phylogenetically unrelated groups of plant species that thrive along tropical and subtropical coastlines and adapt to saline environments in intertidal zones.

The world’s total mangrove area is approximately 18.15 million hectare, with estimates of Indian mangrove wetlands ranging from 6,81,000 - 5,00,000 hectares. The mangroves of Gujarat (22.55%) — most of them on coast — are the second largest after the Sunderbans (46.39%) in the mainland of India.

Among the inland mangrove communities, Avicennia marina represents the only sacred grove species. In general, it can be found in the intermediate tidal zone, but the sacred, land-locked grove of mangrove in Shravan Kavadia has no surface connection to the sea.Threats

The increasing rate of mortality of Avicennia marina, observed from 1998 to 2013, may be ascribed to a combination of 1998 cyclone that uprooted several trees and an erratic precipitation from 1932 to 2001 in Bhuj taluk. Decreased rainfall, increased temperature and evaporation had led to increased salinity, which in turn decreased seedling survival, growth and net primary productivity. Mangrove area is reduced because of the conversion of land into a hypersaline flat.

“The seedlings don’t need salinity. But decrease in precipitation results in increased salinity due to reduced water input to groundwater,” Nimisha explains. The survival risk of the sacred grove is further aggravated and triggered by the invading alien species, P Juliflora. Wood borers on these shrubs too pose a threat to the inland mangrove. Sensing the need to conserve the unique forest land, the National Board of Wildlife did not sanction construction of a road piercing the Kutch desert sanctuary. 

Taking cue from restoration programmes involving coastal mangrove forests, scientists felt that the survival of the world’s only inland mangrove deserved immediate attention. “We approached the Gujarat Biodiversity Board and the Ministry of Environment and Forest for support,” Nimisha adds.

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