Shrinking terrain and shifting habitats: How the Bandipur fires may be impacting tigers

South India’s tiger population is thought to be the “world’s single largest,” but man-made fires are becoming more and more of a threat to their terrain.
Shrinking terrain and shifting habitats: How the Bandipur fires may be impacting tigers
Shrinking terrain and shifting habitats: How the Bandipur fires may be impacting tigers
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After fires roared through around 15,000 acres of Bandipur Tiger Reserve this past February, the woodland savanna it left behind looked in many ways like a photo negative. Black bark replaced the lighter tones of unburnt wood, white ash splattered across dark earth, and an eerie emptiness took up the space meant for an array of plants and animals, including that most famous and elusive creature that gives the reserve its allure.

South India’s connected woodland savannas of Bandipur, the Wayanad Wildlife Sanctuary, and the national parks of Nagarahole and Mudumalai were estimated to be home to more than 570 tigers as of 2014, the last time tiger census data was published (though new data is expected to be released this month). That population is thought to be the “world’s single largest,” according to the report. The Western Ghats as a whole was estimated to have 685-861 tigers, a number that has gone up in part because researchers and their cameras have gotten better at spotting tigers outside protected areas, but also because these mosaics of grass and trees are largely unbroken by man-made intrusions such as cities, roads and train tracks, giving tigers the ample space they need to roam, hunt and mate. Fires, however, are a different type of man-made issue that are becoming a larger threat to their terrain.

TNM spoke to numerous experts on fires in south India and all agreed that the vast majority of them are caused by people. Farmers burn off stalks in their fields and the blaze gets out of hand, villagers inside protected areas set fire to brush as revenge for what they see as forest department encroachment on their homes, and tourists toss smoking cigarettes out car windows onto twigs dry as kindling. This isn’t new, but there is evidence that these blazes now more often turn into the kind of fire storms that decimate trees and make headlines.

“The fire has become more and more destructive,” said BK Singh, the former principal chief conservator of forests for Karnataka. “You can’t get control over it for sometimes even five-six days.”

The fires in Bandipur Tiger Reserve in February 2019. (PTI)

These firestorms have begun to come every two or three years, enough time for regions of brush to thicken and turn small fires into something much more dangerous.

Oceanographers say monsoon rain is likely to become more erratic, and south India — like the rest of the planet — is warming up, meaning its woodland savannas are likely to spend even more time dry and starved for water, ready to burn. What this means for tigers, though, is far from clear.

Adapting to fires

When a fire rips through a huge chunk of trees and grass, scientists say animals are often able to get out of its way well before their lives are at risk. After a blaze has burned itself out, forest department officials don’t find much in the way of blackened bones.

Tigers follow the animals they prey on, and they too will clear out of the fire’s path.

“Things like tigers are quite tolerant of disturbance,” said Abi Vanak, an animal ecologist at the Ashoka Trust for Research in Ecology and the Environment. Like nearly all animals and plants that make their home in South India’s woodland savannas, fire has long been a part of their lives.

That symbiosis is evident in the way the region’s trees have evolved -- thicker bark than their evergreen counterparts, and saplings that quickly burst back to their pre-fire height so long as their roots survive. Studies show that fire is even a necessary part of the ecosystem’s survival -- its flames make sure trees don’t crowd out the grass and that canopies don’t thicken enough to blot out the savanna’s much-needed sun.

Come back to Bandipur a year after a fire, said T Balachandra, director of the reserve, and it will be easy to see how much the landscape has recovered.

In the middle of April, about a month-and-a-half after Bandipur’s major fires had burned out, three elephants were already absent-mindedly grazing not far from where the blaze had been until they ran off at the rattling of a forest officer’s jeep. Elephants aren't tigers, but they too need a lot of space to roam, and yet research conducted by Vanak and others in South Africa -- another region prone to fires -- shows that elephants aren't too bothered by periodic burning.

“[Fire] is a natural, ecological process, and it should be seen as one,” he said.

The aftermath of a fire in Bandipur Tiger Reserve, on April 12. (Photo: Colin Daileda)

Shifting habitats and shrinking terrains

Surviving in a warmer climate also shouldn’t be too much of an issue for tigers, said Latika Nath, a tiger conservation expert. They can do just fine in tropical forests or woodland savannas, and can make their home in places where the temperature dips below freezing or climbs beyond the scorching heat of a Delhi summer.

“The existence of habitat is more important than the change in temperature, for a tiger,” she said.

Temperature changes might not put much strain on a tiger’s body, but those changes may start to warp their habitats in ways that could press them to leave or change how they survive in the habitat they’re accustomed to.

Tigers have already been found in the Himalayas, not exactly a place they’re known to frequent.

But in hotter climates, Nath explained that tigers will probably need to find new sources of water. As lakes and ponds dry up, they might be forced to become more social, sharing one pond among three of them when they each used to have their own.

Changing rainfall patterns may also shrink the amount of water that falls over these woodland savannas. The increasingly erratic monsoon could also dump half a season’s worth of water onto the grass-tree mosaics in a day and then leave them to dry, rather than spacing out rainfall so tigers have a few watering holes from which they can consistently drink.

Lack of water, hotter temperatures, and a drying climate could combine to shrink the amount of ideal terrain for tigers, and those conditions are ripe to help a small fire grow into something much more wild.

“The habitat will definitely reduce,” said Dipanjan Naha, a tiger habitat expert at the Wildlife Institute of India. If available space shrinks, he said it would put more pressure on the remaining “patches” of ground still partially covered with trees.

The effects of climate change — be they more intense fires or something else — have yet to splinter the south’s woodland savannas, but the constant construction of roads and ever-expanding cities has. More roads and buildings in formerly tree-covered ground means more human activity, which means greater potential for damage from any number of things a person can do, such as drop a warm match or fail to put out a crop fire.

“Fragmented forests are subject to a lot of anthropogenic pressure,” Singh said. That pressure could result in fire that flushes tigers from their turf and creates “the potential to have more human-tiger conflict.”

Anyone who reads the words “human-tiger conflict” probably thinks of a person who found himself on the sharp end of gnashing teeth, but tigers can wind up the victim when they wander into electric fences put up by villagers keen to guard their crops. The big cats may also have to figure out how to traipse into another tiger’s region without starting a fight.

“We don’t know how they get accepted in a different area,” said Sanjay Gubbi, a conservation biologist at the Nature Conservation Foundation who has worked to limit habitat fragmentation. “Do they get killed?”

A driver guides a government jeep along a dirt road through Bandipur Tiger Reserve, on April 11. (Photo: Colin Daileda)

Altering woodland diversity in flora and fauna

A list of Bandipur fires from 2012-2017 put together by the Karnataka Forest Department shows that not many large blazes burned the same spots during those years. The woodland savannas will regenerate as long as that continues, but if fires wipe out the same patch of land -- even every few years -- it could warp it in ways that would be hard to reverse.

Regions swamped by flames again and again can lose many of their saplings despite their ability to rejuvenate, so that all the trees in a chunk of terrain are above a certain height and age, like a nation without children to carry on when the adults are gone.

Continuous fire can also deplete soil such that the only plants that can thrive are hearty invasive species. Lantana — once a decorative plant introduced to India during colonial times — has become an invasive weed that dominates much of the ground in the woodland savannas of reserves such as Bandipur. It’s thick enough to keep tigers from ranging through wide swaths of land, and when the weather dries, it allows to climb to the tops of trees.

“I’ve seen adult trees killed by those kinds of fires, and I think if you’re going to be seeing more and more of these — whether it’s because of increased frequency of droughts or whatever — I think these forests might change,” said Ankila Hiremath, a plant ecologist at the Ashoka Trust for Research in Ecology and the Environment. She stopped well short of predicting doom for the landscape, but Hiremath did say there’s a chance that fires could alter the diversity of woodland savannas over time.

“You might have a weeding out of trees that cannot handle these canopy fires,” she said.

Colin Daileda is a freelance journalist in Bengaluru who has written about climate change for Thomson Reuters, and on other subjects for The Atlantic, Roads and Kingdoms, Mashable, and others. 
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