Assam: Overcrowded, shrunken habitats leave tigers weak in their strongholds
An adult male tiger that had been trapped in the fringes of the Orang National Park and Tiger Reserve on November 28 was brought to the Assam State Zoo for treatment.
“The tiger has severe injury marks that might have been from infighting,” says a frontline staff member of the park.
Straying incidents are common during winter months but over the years straying and infighting that leads to tiger deaths have become common throughout the year as seen in tiger reserves like Orang and Kaziranga in Assam, Northeast India. Earlier, on 4th November, an adult tiger was found dead in Orang. The Divisional Forest Officer Pradipta Baruah confirmed the tiger died in infighting.
Three tiger deaths were reported from the famous Kaziranga National Park and Tiger Reserve between June and July this year. While Kaziranga National Park (KNP) authorities confirmed infighting as the cause of death for two tigers, in another incident an adult tiger was found dead with a bullet wound in the fringes of the park. Official sources said that the tiger was hit by “accidental” firing on June 17 when irate villagers pressed forest guards to fire and chase away the predator attacking their livestock.
Park authorities have faced increased challenges from such straying incidents that pose serious threat to both humans and animals.
“Straying incidence throughout the year, unnatural death of juvenile, sub-adult or individual which are over mature, infighting between breeding males and even other age groups due to scarcity of food are some primary signs of habitat shrinkage,” says Bhupen Talukdar, an ex-official of Assam forest department.
When the natural habitat of animals is destroyed, it leads to decline in their primary food supply and breeding grounds and their numbers get drastically reduced.
Floods and erosion:
Over the years threats to Assam’s tiger reserves like Kaziranga and Orang have increased manifold. While poaching remains a pressing concern, there have been issues from shrinking of habitat, encroachment in wildlife corridors, siltation of water bodies and on top of that--recurring floods and erosion. Erosion has led to shrinkage of habitat and brought people face to face with wildlife.
Local people have encountered wild boars, elephants and tigers from the Kaziranga National Park in their homes during high flood. Last year. Prabin Saikia’s family at Baghmari under the Bagori Range had found a tigress lay snug inside the warmth of their home!
The family stayed out of the house while a team from the Centre for Wildlife Rehabilitation and Conservation (CWRC) shifted the sub-adult tigress to the Centre using tranquilizers, to be finally released in the wild two days later. The CWRC team transported another tiger days before from a goat shed at Kandulimari village in the Agaratoli Range of the Park.
Rare and endangered wildlife straying out of the protected areas to escape surging waters and taking refuge in tea plantations and human habitations have become quite normal.
River bank erosion cause shrinkage to protected areas:
More than floods, erosion by the Brahmaputra and its tributaries has become a much bigger problem for Assam— its land, people and its famed biodiversity. Shallow riverbeds with reduced water carrying capacity, change in rainfall patterns and regular seismic activity have contributed to river bank erosion.
In 2012, a study of riverbank erosion by the Brahmaputra undertaken by Prof Jogendra Nath Sarma and Prof hukla Acharjee of Dibrugarh University, showed that Kaziranga National Park had lost 8,120 hectares between 1912 and 2008.
Erosion, which is quite irregular in pattern, is the major threat to the National Park. A significant amount of the Park’s core area has been lost, including some anti-poaching camps and thickly forested area. It was found that a location under attack of severe bank erosion during one flood season may or may not experience a similar attack during next season rendering the protection work futile.
The North Eastern Space Applications Centre (NESAC), Shillong in its analysis of land cover dynamics in Kaziranga National Park using geospatial technology also found flood, erosion and habitat loss to be the main threats plaguing Kaziranga.
A study published by NESAC in February 2021, showed that flooding and erosion had led to a “huge landmass loss” along the northern and eastern parts of Kaziranga.“Erosion is the main cause for the loss in KNP area and the Eastern range of the Park is the most affected one,” said Haobam Suchitra Devi, Senior Scientist, NESAC.
“Since the 1950s we have shifted our homes at least six times,” said Dhakum Doley, whose family is one of several hundred who lost their homes and land to erosion and were forced to live in an embankment in Dhansirimukh.
The area - where the Dhansiri River meets the Brahmaputra near the Eastern Range of Kaziranga National Park--is mostly inhabited by the indigenous Mishing tribe. “Every year, the river has been eroding huge areas,” says Dhakum.
Decreased habitable land in the Brahmaputra valley:
Comparative bank line studies on the Brahmaputra indicate erosion to be much higher than land formation indicating a trend of more riverine areas and decreased habitable land in the Brahmaputra valley.
In 2018, Assam government data showed a total of 427,000 hectares of land been lost due to erosion since 1950— or 7.4% of the state’s total area. An average of 8,000 hectares of land is lost to erosion each year, rendering hundreds of thousands of people homeless.
The Union Ministry for Water Resources data revealed that erosion has rendered some 86,536 people landless in Assam from 2014 to 2019. However, Assam Revenue Department found these figures tentative as the exact number of people keeps changing with new areas getting eroded every year.
Resettlement of all erosion-hit families remained a complicated exercise as people who have lost their land and livelihood want to be resettled in areas closer to their original homes rather than in a new area. Thousands of such families have been living on embankments in temporary shelters waiting for the government to rehabilitate them, while non-availability of revenue land in the preferred areas force others to settle in the fringes of forests or sometimes inside protected areas.
Habitat shrinkage and loss of connectivity affecting tiger populations:
India is home to around 70% of the world wild tiger population and nearly 93% of the total tigers in India are concentrated in the 12 states of Arunachal Pradesh, Assam, West Bengal, Bihar, Orissa, Uttar Pradesh, Madhya Pradesh, Rajasthan, Maharashtra, Andhra Pradesh, Tamil Nadu and Karnataka. Tiger Reserves in Assam –Kaziranga, Manas, Orang and Nameri - together hosts some 200 tigers.
The Nameri-Pakke-Manas are connected landscapes with issues of loss and shrinkage of habitats. Encroachment has also crippled the Manas National Park - a World Heritage Site with a population of some 48 tigers. Villages have grown to over 50 inside the protected area in the last two decades with drastic reduction in forested area under Chirang, Kolmou and the Kuklung Range.
Kaziranga - a source population area for Royal Bengal Tigers with an excellent prey base -- has the highest tiger density among protected areas in the world. This high density of tigers in KNP has also been a cause of concern. “In general, a male tiger in Kaziranga lives short. They are vulnerable to injuries and get killed during infighting even due to small injuries.
Adult tigers photo trapped in 2009 were not seen in 2014 photo traps. Life is harsh for tigers in this high density-tiger habitat. The KNP area has grown over time from 430 sq km to about 800 km. However, exact tiger habitat has not grown and therefore density of population is saturated,” says Firoze Ahmed, Biologist and Head of Tiger Research & Conservation Division, Aaranyak.
“Population increase beyond its carrying capacity also degrades the habitat and degraded habitat reduces the population,” said Bhupen Talukdar.
Although the mega carnivore Panthera tigris is known for its resilience in human-dominated landscapes, overcrowding and inbreeding can lead to undesirable genetic variants that leave the feline vulnerable to diseases.
Tiger population in India has more than doubled between 2006 and 2018 to reach an estimated 2,967 according to the National Tiger Conservation Authority. But this alone is not enough to ensure the species’ survival. While the recent estimates of wild tiger populations showed a positive trend in more than 100 years, in realty the tiger is not out of danger.
Restoring dispersal corridors top priority for survival of KNP tigers:
Ever-increasing human interference has disrupted the ability of tigers to move. Habitation, industries and infrastructure development led to the loss of natural corridors and connectivity with adjoining forests.
“Restoration of natural connectivity and corridor dispersal routes to link tiger habitats--Orang, Nameri, Loakhuwa and Burachapori has become top priority to conserve breeding populations and reduce competition for survival of the species,” said P Sivakumar, the director of Kaziranga National Park.
The Orang National Park - a satellite area of Kaziranga National Park--is the smallest national park in Assam with a size of just about 79 square kilometers core area and houses a current population of 34 tigers. They are at risk of being disconnected from tigers in other habitat patches, as almost all corridor value in the North, West and East side being lost to encroachment.
When it comes to tiger conservation, apart from the threats of habitat destruction and poaching, conflict between tiger and people had posed a bigger challenge.
A few years back, “Julie”, an adult tigress, was brought from Orang to the State Zoo to treat an infection in the eyes. It was later found that “Julie” could not prey due to poor eyesight and used to frequent human habitation in the fringe of the Park for easy prey. Initially, the zoo veterinarians were not sure what caused the infection that gradually led to loss of eyesight in the tigress. They suspected the infection was from poisoning. There had been instances of tiger deaths caused by poisoning in the fringe of Orang.
“With habitation all around like a hard boundary, and frequent human-wildlife conflicts, the only corridor now left is the Brahmaputra River that forms part of the buffer area,” says Sandeep Bendi, who had been Divisional Forest Officer of Orang.
Proposal to bring Brahmaputra chars under Protected Area:
While erosion by the Brahmaputra has led to shrinkage of important wildlife areas, the river also creates new areas by depositing sand bars or chars. This is how the flood plain ecosystem works.
“The Brahmaputra is a braided river which runs by dividing its flow in a number of sub-channels. Although both of its banks are nearly linear, the channels carrying water are sinuous - similar to the meandering rivers. They show curvatures and get divided into two or more channels creating bars (chars) in-between. The bars are the deposits of sediments of the river. One of the factors for development of these features is bank erosion,“ said Prof Jogendra Nath Sarma, Rtd. Head of Department of Geology, Dibrugarh University.
The sand bars aid migration of tigers and other mega species. The Brahmaputra river system is vital for tiger movement. Sand bars also serve as a good habitat of different species. More the diversity of biotic and abiotic factors in an ecosystem more is its strength and stability.
“These are areas where animals would try to move in but if that particular area is not a protected area it is difficult to ensure their safety because these chars are also used by the landless people, whose settlements are barriers to the tigers,” says Bendi.
The contiguity of important migrating routes for wildlife thus gets blocked by human settlement. This calls for a legal boundary of flood plain ecosystem large enough to take up a lot of riverine areas within it. Authorities of Orang National Park have already submitted a formal proposal for expansion of the Park area with additions of the Brahmaputra riverine area on its southern side to connect Orang with the Kaziranga landscape – seen as the only corridor of value.