Once an ecological hotspot, Nilgiris face higher temperatures and changed rainfall pattern

Vasanthan Panchavarnam came to Coonoor 30 years back on a transfer from Chennai as a physician. The hilly district stole his heart and he decided to make it his permanent home. When some friends who he hung out with became interested in exploratory walks, “We picked up the binoculars and started going around. The change we have observed is tremendous,” he told IndiaSpend.

Nilgiris is situated in the northwestern part of Tamil Nadu and the Western Ghats between 900 metres-2,636 metres above mean sea level. More than half (56%) of its total area is under natural vegetation.

Thirty years back, when Panchavarnam relocated, it was a quiet town with a flourishing local ecology. The rolling grasslands, dense woods and cool climate captured the hearts of nature lovers. But once it started attracting tourists and businesses, leading to landscape alteration and subsequent warming, the town started to lose its biodiverse verdancy, native flora, and wildlife.

Temperature, rainfall

Temperature fluctuations in the Nilgiris have been observed for the last two centuries and several references to it are found in books and hunters’ journals, Panchavarnam tells us.

The Neilgherries, a popular travelogue published in 1857 detailing the travels of medical superintendent Robert Baikie in the district, says that between 1831 and 1833, the mean temperature was 16.8 degree Centigrade (now Celsius). Between 1901-’06, it was 13.8 degree Centigrade and in 2016, the mean was 24.1 degree Centigrade.

The British had begun exploiting the land over two centuries ago. “The three major towns in the geographical domain from Kodanaadu to Naduvattam namely Coonoor, Kotagiri and Ooty were exploited with buildings and plantations,” says Philip K Mulley, a septuagenarian resident, pastor at the local church, and long-time chronicler of the Nilgiris.

Over the last five decades, the rainfall pattern has been changing in Nilgiris; there have been short, intense spells with drop in average rainfall in particular years, says S Vishwanath, a water expert and educator based in Bengaluru.

As per the department of Horticulture and Plantation in Nilgiris, the average rainfall for the district is 1,522.7 mm per annum.

“The aquifers are not recharged and so the springs do not flow,” Vishwanath told IndiaSpend. “If the springs do not flow, reservoirs do not fill up. Then, there is shortage of water both for nature and living beings. The springs affect the wetlands and bogs which in turn impacts the grasslands also. Moreover, with the recharge zones being altered, there is a chance of forest fires since the soil moisture is deficient. Temperature also increases because there is not enough humidity.”

In 1850, the British planted Tasmanian Blue Gum (Eucalyptus globulus) and Black Wattle (Acacia Mearnsii) for the purpose of getting firewood. The weed species Lantana Camara also came into the hills at the time, as part of ornamental plantation. These invasive species spread across the pristine habitat of the Nilgiris, altering its properties and making it vulnerable, says Panchavarnam.

“It started spoiling the grazing grounds and teak plantations in Teppakkadu. Sandalwood also encountered a rare disease because of Lantana. Wherever forest cover is disturbed, there is Lantana in Nilgiris. From a diverse ecosystem, it has created an alternate one, with structural, nutritional and species simplification. The loss of diversity is further adding a block to mitigating the impact of climate change,” he explains.

Loss of native species

“Shola” is a name used across South India to refer to swathes of montane grasslands and shrublands–biomes, as per World Wildlife Fund classification. Shola habitats in the marshlands of Nilgiris comprise stunted evergreen trees and undulating meadows. These have moisture retention properties and act as carbon sinks.

When it rains, the Shola grasslands absorb the water, preventing surface run-off. With its deep roots that go seven feet under, it retains the water underground. The Shola ecosystem supports the growth of native species that are endemic to the region.

“These habitats are now filled with Eucalyptus, Acacia and tea, as also Lantana, none of which have soil-binding root systems,” says Panchavarnam. “The result is that the run-off is heavier, and the resulting soil erosion degrades the marshlands. With the dams taking over whatever is left of the marshlands, the drastic landscape alteration and the increase in temperature have led to the loss of certain native bird species. Thousands of migrant bird species have stopped coming to the region. Woodcock or game bird that are marshlands-dependent are rare now. Egyptian vultures are extinct from the upper reaches, as is the Malabar civet. Recently, some lost species are re-colonising because of forest loss,"

Woodcutters, foragers, animal-grazers, and hunters add to the damage. The population of the Nilgiris is more than 700,000 and the area is experiencing rapid commercialisation. “Most of the wetlands are replaced by buildings within the urban limits of Kotagiri and Coonoor,” Mulley laments.

Climate change impact

“Climate-change impact is felt both in loss of livelihoods and man-animal conflict. Last year, both monsoons failed and the district received heavy rainfall up to 50 cm overnight. This resulted in landslides; all the vegetables ready for harvest were washed away in the heavy downpour,” says Azad Kamil, Founder, Ongil Nature Trust, a non-profit in Coonoor that works to spread awareness about nature conservation.

Except the native tribes such as Kurumbars, Irulars, Todas, Paniyars and Kattunayakars, many locals have left their properties behind and migrated to the plains in search of reliable occupations. Meanwhile in localities like Rambla that are dominant with tea estates, many gated communities have mushroomed. This area was habituated by species such as Sambar deer, rabbits, Leopard and leopard cats.

“Because of afforestation and encroachment, these do not have enough habitat to thrive. In fact, large carnivores are lesser in number now and so the population of herbivores such as bison and bears have become more and they are entering the towns and turning into a menace,” explains Panchavarnam.

“Usually cobras are not found in winters. But two Cobras were rescued last week in Kethi. Two years back, we rescued a 13-foot King Cobra in Kattery, located 3 km from Coonoor. Peacocks, abundant originally in Mudhumalai, are sighted in Coonoor. The most important is mosquitoes in the hills during winter,” adds Kamil.

Undoing damage

The climate change being experienced in the Nilgiris is anthropogenic. Lantana, that is present everywhere except the upper reaches, cannot be removed totally, says Panchavarnam, because if even a small root is left, it grows and spreads rapidly. Also, because of the inedible nature of its leaves, herbivores cannot consume it. But the berries are edible and so the seeds get dispersed.

In order to conserve the remaining ecosystem and prevent soil erosion and water shortages, says Vishwanath, “A focus on spring protection and rejuvenation and identifying and conserving natural recharge zones is essential.”

In 2014, the Tamil Nadu Forest Department conducted a campaign to remove many exotic species in the Nilgiris biosphere reserve, such as Acacia mearnsii, and the native sholas planted in the region have started to reoccupy the canopy gaps, said Rekha R Warrier, a scientist at the Institute of Forest Genetics and Tree Breeding, Coimbatore.

Being unique, the sholas require a long-term perspective and a socioecological landscape management process implemented in a participatory manner with Indigenous Peoples' communities interested in protecting their traditional values.

The findings of a case study that she conducted and reported as part of a working paper on forest and Landscape Restoration supported by the Food and Agriculture Organization of the United Nations in three selected shola pockets in Nilgiris suggest that these open patches should be fenced, and that native species should be reintroduced.

“Species able to establish in open landscapes, such as Syzygium cumini, can be beneficial in restoration initiatives. Of course, projected changes in rainfall patterns and temperature could endanger intolerant endemic species, due to their narrow genetic base and restoration of species with small population sizes is a challenge, and introduction from adjacent forest patches would be necessary to increase their genetic diversity,” she told IndiaSpend.

Public-led conservation efforts, in coordination with the district collector’s office, are aimed at replanting Shola grass and remapping water resources to prevent further degradation.

The administrators need to bring strict rules and follow them diligently, feel residents. “The Nilgiris biosphere zone should be considered in isolation – the general conservation rules made for the state of Tamil Nadu can’t be applicable here,” Mulley voices the collective view.

“Developing a carrying capacity and environmental management plan and most importantly, relooking at the Gadgil Committee report on the Western Ghats and implementing its recommendations,” concludes Vishwanath.

This article first appeared on IndiaSpend, a data-driven and public-interest journalism non-profit.