KAZIRANGA, Jan 21 - Even as Kaziranga National Park grapples with a problem of plenty with herbivore populations, including that of the rhino – its flagship species – increasing every year, serious space constraint looms large over the celebrated rhino-land as unabated erosion by the Brahmaputra continues to erode its landmass.
Erosion has been particularly severe at the Agoratoli Range, the easternmost part of the park. Worryingly, a good portion of the rhino habitat in the area has been lost in the Brahmaputra that runs parallel to the park along its entire northern boundary.
This has effectively led to a decline in the rhino numbers at Agoratoli. Conservationists feel that if left unaddressed, the issue can turn grave, given that a substantial portion of the eroded forestland used to be prime rhino habitat.
“Erosion along the eastern and northern part of Agoratoli has been a real problem. Unabated erosion over the years has eroded some 35 sq km of prime rhino habitat there. This has led to a reduction in rhino numbers at Agoratoli and also a spurt in the incidence of rhinos straying out in search of food and space,” Park Director Akashdeep Baruah told The Assam Tribune.
Baruah said that plans were afoot to put in place an effective anti-erosion mechanism along the affected areas. “We are trying to bring in the best of practices, including those from outside,” he said.
As Kaziranga’s ecosystem is intertwined with the annual floods that replenish its wetlands and floodplain habitat, the anti-erosion measures will have to ensure that floodwater is not prevented from entering the park.
“Raised embankment cannot be an answer to the problem because preventing floodwater from entering Kaziranga’s habitat will spell doom for its ecology. The floods that inundate the park every year are a boon that sustains its floodplain habitat,” Baruah said.
According to a 2014 study by researchers from Delhi University’s Department of Geography, the area available for each rhino in Kaziranga had decreased since 1990, while the number of rhinos had gone up. The study said the area available for each rhino during 1990 was approximately 0.31 sq km, which decreased to 0.16 sq km during 2009.
A conservationist well-versed with Kaziranga’s landscape said that checking erosion through un-raised barriers like stone spars could be tried if the erosion worsens further. “It is wise not to tinker with natural systems but if the erosion gets worse, some preventive steps would be necessary,” he said.
Some conservationists believe that the problem of erosion in Kaziranga is not acute, more so in view of the fact that the loss of land from erosion is compensated by accretion due to sediment deposition on another side through a natural process.
According to a study, the period from 1912 to 2008 saw the loss of a total land area of 150.04 sq km due to erosion by the Brahmaputra. At the same time, a total landmass of 61.86 sq km got added, resulting in overall loss of 88.18 sq km land.
“Erosion had not reached alarming levels in Kaziranga but of late it is turning severe at Agoratoli. Some landmass has been lost to erosion but new areas, too, have come up. At the moment, erosion along the northern boundary of the park from Agoratoli to Arimura is a matter of concern,” he said.
The study was divided into periods – 1912-1916 to 1972, 1972 to 1998, and 1998 to 2008. The total area eroded during 1912-1916 to 1972 was 84.87 sq km as compared to accretion of 24.49 sq km due to sediment deposition. The total area eroded during 1972-1998 was 44.769 sq km as against the addition of 29.47 sq km, and the total area eroded during 1998-2008 was 20.41 sq km as compared to accretion of 7.89 sq km.
The rates of erosion during 1912-1916 to 1970, 1970 to 1998, and 1998 to 2008 were 1.46 sq km, 1.59 sq and 1.021 sq km per year, respectively.
As the core area of the park is having a high density of rhino, elephant, wild buffalo, swamp deer and tiger, any reduction in prime forestland inside Kaziranga should be treated as a worrying development.