The pastoral Toda community in the upper Nilgiris is losing its Shola grasslands to invasive species
Invasive species such as acacia have taken over 66 per cent of the Shola grasslands (Photograph: Ishan Kukreti CSE) WHEN I was young, we had 120 buffaloes. Today, just 10 remain and getting fodder for them is an everyday challenge for us,” says 65-year-old Nila Vadi, as she waits for her husband at their house in Tamil Nadu’s Tarnardmund village in the upper Nilgiris. The house is built on a gentle slope of a hill, covered with light green grass and small forest patches. Together these two vegetations form the famous Shola ecosystem of the upper Nilgiris, one of the highest mountains in the Western Ghats, with peaks and plateaus ranging from 1,700 to 2,600 metres. Owing to the altitude, the Shola forest patches occur only in the folds of the mountains that receive the least fog or mist.
Standing outside Vadi’s house one can see that the mosaic of green is interrupted at places by rectangular farms of vegetables like carrot and cabbage. One such carrot farm is on Vadi’s land, but her family does not cultivate it. “Farming is expensive so my husband works as a labourer on his own farm which we have leased out.” Vadi belongs to the pastoral Toda community, a Particularly Vulnerable Tribal Group settled only in four Nilgiri blocks—Ooty, Kotagiri, Gudalur and Coonoor. Her family owns 5 hectares and farming each hectare requires an investment of Rs 4 lakh, which no household in the community can afford. So, they have leased out the land to rich farmers from Ooty who pay them Rs 1.4 lakh a hectare and employ them as labourers.
She blames invasive species such as acacia, lantana and scotch broom for pushing her community out of cattle rearing. “These species have almost replaced the grasslands in the Nilgiris, which sustained our cattle,” she says. The invasive species took over 340 sq km or 66 per cent of the original grassland ecosystem between 1973 and 2017, says a 2018 study by non-profit Ashoka Trust for Research in Ecology and the Environment (ATREE), published in the journal Biological Conservation. Hearing three petitions filed in 2014, 2016 and 2017 that demand steps to stop the invasive species, the Madras High Court had formed an expert committee. The interim report of the committee, released in September 2019, says invasive species will soon take over the entire Nilgiris vegetation.
The decay of the pristine Shola ecosystem started over half a century back when the government decided to introduce acacia plantations in the region for economic gains. “The forest bureaucracy, which usually views grasslands as waste, decided to introduce acacia in the region after India stopped importing tannin from Africa in the 1960s. Tannin, found in the bark, pods and leaves of acacia, is an organic substance used for preserving leather,” says Milind Buyan, co-author of the ATREE study. After their introduction, the invasive species proliferated due to changing weather pattern. “Over the years, the nights have become warmer and the amount of frost has reduced in the Nilgiris,” says R Sukumar, a scientist at the Indian Institute of Science, Bengaluru. This has allowed the acacia plantations to move beyond the Shola forests and enter the grasslands. Frost traditionally restricted the forests in the Nilgiris from expanding as it “freezes the groundwater and stops the sapling from sprouting in new areas”, says Sukumar.
THE SCALE OF proliferation can be gauged by considering the fact that the invasive species have also taken over the wetlands in the region. “We would earlier take our buffaloes to the Nanjanad region which had 20-30 wetlands that extended to several kilometres. Now they have been replaced by pine and acacia plantations,” says Thortey Gooden, who belongs to the Toda community. He adds that the rise of invasive species has also increased human-animal conflict in the region. “Traditionally, the grasslands allowed easy spotting of carnivores when they would move out of the forest to attack buffaloes. But now, they hide in the acacia forests, which surround most Toda settlements,” he says.
The reduction in wetlands also means that certain types of grasses are disappearing. “The awvul grass (Eriochrysis rangacharii), which is found only in the upper Nilgiris is becoming increasingly rare. The Todas use it for making temple roofs,” says Tarun Chhabra, author of The Toda Landscape. Not only has the number of wetlands gone down, the amount and time of rainfall in the area has also reduced, warns Jagdish Krishnaswamy of ATREE, who co-authoured the Intergovernmental Panel on Climate Change report on global warming. This has hit the flowering pattern in the region. “The main flowering season is between December and March. But blooming of white kurinji (Strobilanthes kunthiana) and jamun (Syzygium cumini) has reduced due to the changing rainfall. The bees depend on these trees for pollen,” says P Chandran, who belongs to the honey-gathering tribe of Kurumbhas in the Nilgiris. He adds that some 20 years ago, every cliff had 60-70 beehives, which has now reduced to just four or five.
The ecosystem degradation is forcing the tribal population to migrate to nearby Mettupalayam, Tiruppur and Coimbatore districts for work, says the Nilgiri District Human Development Report, 2017. The district population declined by 3.55 per cent between 2001 and 2011 Census reports to 73,500. Gooden says the tribal population will dwindle further if the invasive species are not checked. “Without us, the fragile Shola ecosystem will also get lost forever,” he says.
This was first published in Down To Earth's print edition (dated 16-30 November, 2019)
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