Nilgiris threatened by climate change

Amongst the most fragile ecosystems in the world, the Nilgiris in Tamil Nadu is bearing the brunt of climate change evident in the increasingly erratic rainfall and higher temperatures.

By Sibi Arasu

The Awvul grass (Eriochrysis rangacharii) is found only in wetlands located in the upper reaches of the Nilgiris district in Tamil Nadu. It is considered sacred by the Todas, a pastoral tribe indigenous to this region.

“We use Awvul to thatch our temples. It is the tradition for Todas to collect them from the swamps and wetlands,” Northay Kuttan, president of the Nilgiris Primitive Tribal People’s Federation, told indiaclimatedialogue.net. “In the last few years though, because of erratic rainfall, many swamps have dried up and it’s becoming ever rarer to find Awvul.”

The reduction of grasslands has adversely affected the Toda buffalo as well. The Toda buffalo is a genetically isolated population found only in the Nilgiris. It is sacrosanct to the Toda people. “When I was a child, this whole region was filled with grasslands and there was enough pasture for our buffaloes,” Kuttan said. “It is only in the last few decades that exotic plant species such as the eucalyptus and acacia have taken over.”

For tea, paper and fire

The Nilgiris district, part of the 5,520 sq. km Nilgiris Biosphere Reserve, is a UNESCO World Heritage Site and a biodiversity hotspot. The district has an average elevation of 1,800 metres above sea level and is defined by its evergreen shola forests and montane grasslands. The region was mostly untouched till two centuries ago, but has witnessed large-scale destruction ever since.

The first step in the region’s decline was the culling of grasslands to set up tea plantations during the colonial period, which occupy great swathes of the mountains now. This was followed by planting of exotic species such as the eucalyptus and the wattle, which served as raw material for firewood and paper for a newly independent India.

Montane Shola forests in Sakleshpur-Mudigere. Photo by L. Shyamal / Wikimedia Commons CC BY-SA 3.0

Finally, in the last decade or so, there is a slew of construction of hotels, weekend retreats and bungalows by people from nearby urban regions such as Chennai and Bangalore, choosing to either frequently visit the mountains or to migrate and settle down here.

Despite efforts by conservationists, the forest department and government authorities to preserve what is left of this ecosystem, human pressure is consistently causing decline. Climate change in the form of unpredictable rainfall is also taking a heavy toll on the region’s indigenous population — be it people, plants or animals.

Long-term patterns disrupted

“There has been a decline in the amount of rainfall received in many parts of the Western Ghats since the 1950s. At the same time, the proportion of rain falling in the form of more intense rain has increased,” Jagdish Krishnaswamy, senior fellow at the Ashoka Trust for Research in Ecology and the Environment (ATREE), told indiaclimatedialogue.net.

Krishnaswamy, an eco-hydrologist by training, has been observing developments in the Nilgiris region since 2012. “The challenging part is none of the climate models have been able to capture the decline in the Indian monsoons. Also, in the Nilgiris specifically, there have been shifts in how the southwest monsoons and northeast monsoons behave,” he said. “Therefore the decline we see in the southwest is not necessarily reflected in the northeast.”

A pair of elusive Nilgiri Martens (Martes gwatkinsii), resting on a fallen log in their natural habitat at Pampadum Shola National Park, Kerala. Read more about the behaviour of the vulnerable Nilgiri Martens here. Photo and caption by Navaneeth Kishor / Wikimedia Commons CC BY 4.0

Since 2012, according to the annual report of the India Meteorological Department (IMD), the annual rainfall recorded in the Nilgiris has varied from 1,446 mm in 2012, 1,534 mm in 2013, 1,957 mm in 2014, 1,720 mm in 2015 and 889 mm in 2016. This is against an expected annual rainfall of 1,920 mm. Also, rather than the rain being spread out over nine months of the year, they are intense at certain times and non-existent at others with no discernible pattern.

“While last year there was good rainfall, the year before the drought was so bad that even some evergreen sholas began drying up,” Godwin Vasanth Bosco, a restoration ecologist based in Ooty, the capital of the Nilgiris district, told indiaclimatedialogue.net. “Even after the rains of the last few months, the land was so dry that all the moisture was soaked up within a few weeks and parts of the lower altitude Mudumalai reserve appear dry again.”

Bosco was trained at the Gurukula Botanical Sanctuary in Wayanad in the neighbouring state of Kerala and is working for nearly a decade to preserve and promulgate endemic plants of the Nilgiris’ sholas and grasslands. “There is also a gradual rise in temperatures over the last decade and it could be that the high altitude plants are not able to adapt to this. Population of endemic plants like the Anaphalis nilgiriana, Helicrisum wightiana and the grass Andropogon polyptychs have been affected. The grasses here are not able to produce seeds and therefore are not reproducing at all,” he said. “This makes restoration work difficult. I recently had to use vegetative propagation to reproduce some rare endemic grasses in my nursery because they were not reproducing naturally at all.” Bosco has documented his decade long work in the Nilgiris in his soon to be published book titled Metaphor Island.

Endangered fauna

The endemic fauna are facing the consequences of erratic weather as well. In a paper titled Climate Change and its Impact on Tropical Montane Ecosystems in Southern India, published in the Journal of Biogeography way back in 1995, R. Sukumar of the Centre for Ecological Sciences at the Indian Institute of Science, and colleagues wrote, “Species that have a temperate affinity could be the first to respond to a warmer climate. One vertebrate species that would be almost certainly affected in the absence of active management is the Nilgiri tahr, a mammal endemic to the montane grasslands of the Western Ghats. A further reduction in the area under natural grassland would increase its risk of extinction. In the Nilgiri hills, the population of the Tahr has reduced from about 400 in 1975 to not more than 100 in 1991.”

Twenty years later, in the book Tropical Conservation: Perspectives on Local and Global Priorities (2016), Sukumar and colleagues draw attention to another adverse consequence of climate change in the Nilgiris — the spread of invasive plants which are able to better adapt to the changing weather.

“The potential impact of climate change on non-forest ecosystems such as the grassland is poorly studied. Montane grasslands (with C4 grasses) at altitudes greater than 1,800 metres above sea level in the Western Ghats are at risk of being overrun by invasive plants (C3 plants),” he writes in the book. “As a consequence of warming, reduction in incidence of frost and competitive advantage of C3 over C4 plants under increasing atmospheric CO2 levels, there are already indications that Australian wattles (Acacia dealbata and A. mearnsii) planted on a large- scale in the montane grasslands and the ornamental scotch broom (Cytisus scoparius) have spread in recent times.”

C3 plants are the most common and the most efficient at photosynthesis in cool, wet climates. C4 plants are most efficient at photosynthesis in hot, sunny climates.

Trying to adapt

“The drought was so severe in 2016-17 that even underground aquifers began drying up. For the first time, because of lack of drinking water, the then collector had to order digging of bore wells for water supply,” Innocent Divya, Nilgiris District Collector, told indiaclimatedialogue.net. “I see this as a critical sign of change in the ecosystem. We have to wake up and act immediately.”

The Collector – the top bureaucrat in a district – has now issued a total ban on digging of bore wells in the region. “We are remapping the water resources in the entire district and are in the process of drawing up a plan to protect them under various central and state government schemes,” she said. “We are also aiming at rejuvenating water systems such as the Segur river, which can prove as a vital lifeline for elephants and other wildlife in our district.”

The lack of predictability in rainfall has also interfered with traditional agricultural practices of the indigenous people of the Nilgiris. It has affected honey production, a major cottage industry in the region.

“I have been told that the flowering patterns of many plants and trees in the region have changed and this is having an effect on how bees forage and therefore having an adverse effect on honey production,” Anita Verghese of the Keystone Foundation told indiaclimatedialogue.net. Verghese and the Keystone Foundation have been working with the indigenous people of the region, including the Kurumbar and Irular tribes, for over two decades.

“What I see is that people who live in close connection with nature, agriculturists, fisher folks, hunter-gatherers, they are all saying they can’t predict the weather any more. There is something changing here and it is quite apparent that this is anthropogenic climate change,” she said. “While we have to mitigate this, I believe we have to allow those with knowledge about the forests to respond to this environmental change. They have to adapt and change certain practices. The government and other benefactors can assist in providing protective measures during this period of change. After all, they have lived here for millennia, and urban society has been around here for only a few hundred years.”

(Sibi Arasu is an independent environmental journalist based in Chennai. You can read his other stories here. | Feature Image by NA Nazeer / Wikimedia Commons CC BY-SA 2.5 IN )

(This article was originally published on indiaclimatedialogue.net – a dedicated outlet for impartial and objective news and views on all aspects of climate change, how it affects India, and what can be done about it. You can read the original article here.)

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