Experts fear damaged food sources and habitat may threaten biodiversity
The Sundarbans, the world's largest mangrove forest of which more than half lies in Bangladesh, once again acted as a natural barrier protecting the country from the worst effects of Cyclone Yaas, as it has done countless times before.
Yet this protection comes at a cost, as the forest ecosystem must bear heavy damage each time to both its flora and fauna.
At least six deer, alive and dead, were recovered until Thursday as they came floating along the flood waters from the forest, a day after the cyclone made landfall. For two days, the entire mangrove remained inundated in saline water pushed in by tidal waves that reached over five-feet during the high tide.
Experts fear for the rich biodiversity of the forest as salt water may remain for quite some time before being absorbed into the soil, turning the land saline too.
“Through a long adaptive process wildlife has survived in Sundarbans but the biodiversity will be affected as their food and habitats have been destroyed,” said Dr Md Anwarul Islam, professor of the Zoology Department at Dhaka University.
“Remaining submerged in saline water can hinder reproduction as well as other diseases to the animals,” he said.
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The southwestern mangrove forest formed on the Bay of Bengal has been working as a buffer between the coastal population and many catastrophic cyclones that ravage the region every year.
Cyclones Aila, Bulbul, Sidr, Amphan and most recently Yaas all at first rampaged the Sundarbans and then weakened as they reached further into Bangladesh.
On Wednesday, water level in the inland rivers and canals in the swamp forest rose five feet over the normal level.
Later it lowered to two feet over normal on Thursday, the same day that some local journalists reported spotting two deer floating in neck high water near Sharankhola range Forest Department office during high tide.
Jahangir Jamaddar, from Chaltebunia village of Sharankhola upazila, told UNB he saw a wild boar drifting toward the forest during high tide.
Meanwhile, of the six rescued deer, four were found alive and later released into the forest, said Sundarbans east divisional forest officer Md Belayet Hossain.
“Climatic change has increased the number of storms of tidal waves of this stature,” said Dr Mahmud Hossain, researcher and vice-chancellor of Khulna University.
“It takes usually 25 years for a forest to get back to its previous state after a calamity but Sundarbans hardly gets the time as such cyclones have become more frequent in recent years,” he said.
Due to unusual high tide, 55 manmade ponds that provided fresh water to the forest staff and wild animals are now filled with saline water, said Md Amir Hossain Chowdhury, the chief forest conservator.
Many animals were seen taking shelter at the high banks of the ponds as water level rose, he said.
For future calamities like this, the Forest Department is planning to build high ramparts for the wild animals to shelter, said Amir Hossain.
Belayet Hossain said at least 11 jetties, six fresh water ponds, two forest offices, one staff barrack, 12 roads and one foot trail have been damaged due to the cyclonic storm and tidal wave.
However, the number of casualties caused by Yaas to the wildlife is yet to be ascertained, he said.