Peril In The Hills: Extreme Weather A Danger For Nilgiri Ecosystem

Godwin Vasanth Bosco reports on extreme precipitation that has fallen on the Nilgiri plateau of southern India the last few years. These extreme and unprecedented rain events have led to massive landslides and other ecological damage. Little has been done to address the crisis.
Featured image: A massive landslide in one of the largest sholas in the Avalanche region of the Nilgiris, with hundreds of native trees and the stream ecology washed away.

Crumbling Ancient Mountain Ecology

Written and photographed by Godwin Vasanth Bosco / Down to Earth

Thousands of trees lay dead and strewn around the western parts of the Nilgiri Plateau in southern India.

Deep gashes scar ancient mountains slopes, standing a stark contrast to the lush green vegetation that they otherwise support. As conservationists, activists, and concerned people in various parts of India are fighting to protect forests and wilderness areas from being deforested, mined, and diverted to `developmental’ projects, there is another level of destruction that is happening to our last remaining wild spaces. Climate change is causing the widespread collapse of ecosystems.

Carbon dioxide levels in the atmosphere have just hit record-breaking levels of 417 ppm in May 2020. It has never been so high in the last 3 million years. Along with global warming caused sea-level rise and the melting of polar ice caps and glaciers, the steep increase in greenhouse gas concentrations has led to a surge in the frequency of extreme climate events. A region of the earth where climate change caused weather extremities are exceedingly apparent are the coastal plains and the Western Ghats regions of southern India. In the last four years, this region has been affected by eight tropical cyclones and consecutive extreme rainfall events during the southwest monsoon periods of the last two years.

These bouts of intense storms have been interspersed with periods of severe droughts, heatwaves, deficient, and failed monsoons.

On August 8, 2019, the Avalanche and Emerald valley regions, which are part of the Kundha watershed, received an unprecedented amount of over 900 mm [2.9 feet] of rainfall in 24 hours.

It broke the record for the highest rainfall ever recorded in Tamil Nadu, by nearly twice the amount. Over four days, this region experienced close to 2500 mm [8.2 feet] of rainfall. To put this in perspective, the nearest city (100 km east) in the plains of Tamil Nadu, Coimbatore, receives around 600 mm of rain annually. The Kundha watershed bore a deluge that was four times the annual rainfall amount, over just four days.

The upper watershed of the Kundha River is a complex of several peaks above 2400 meters and broad deep valleys. The Kundha River, which is a primary tributary to the Bhavani that feeds into the Cauvery, is fed by numerous streams and rivulets at the headwater sections.

With the barraging downpour, nearly every stream and rivulet burst its course. Vast tracts of precious soil and shola ecology slipped away on either side of the watercourses. Gone are the rich black soil layers topped with spongy humus that line the streams; washed away are dark moss and wild balsam covered rocks that shaped the flow of every stream; lost are the thousands of shola trees, dwarf bamboo and forest kurinji that guarded the streams, saplings, ferns and orchids of the forest floor. In place of these are deep cuts of gauged out the earth, revealing the red underlying lateritic soil layers, and lightly shaded freshly exposed rocks.

Numerous large landslides have occurred on intact grassland slopes too.
Uprooted and washed away trees, and dead Rhododendron arboreum ssp nilagiricum trees in a broad valley near the Avalanche region.
Native shola trees and stream ecology completely washed away on either side of tributaries of the Kundha River

Shola-grassland mosaic in danger

The cloud forest ecology, known as sholas, is specialized in growing along the folds and valleys of these mountains. They are old-growth vegetation and harbour several endemic and rare species of flora and fauna. These naturally confined forests are already some of the most endangered forest types, because of habitat loss and destruction.

The recent episode of extreme precipitation caused landslides, have dealt a telling blow on these last remaining forest tracts. What is even more shocking is that montane grassland stretches have also experienced large landslides.

The montane grasslands occur over larger portions of the mountains here, covering all the other areas that sholas do not grow in. Together, the shola-grassland mosaic is the most adept at absorbing high rainfall amounts and releasing it slowly throughout the year, giving rise to perennial streams. Over a year they can experience an upwards of 2500 to 5500 mm of rainfall, which is intricately sequestered by complex hydrological anatomy that carefully lets down most of this water, using what is needed to support the ecology upstream.

The native tussock grasses especially are highly adapted to hold the soil strongly together on steep slopes. However, even this ecology is now giving way under pressure from extreme weather events. The shola-grassland mosaic ecology cannot withstand the tremendously high amounts of rainfall (over 2400 mm) that occur in significantly short periods (over 4 days). Worsening climate change is driving the intensity and frequency of extreme weather events, resulting in a level of ecosystem collapse, never witnessed before.

An example of intact shola-grassland mosaic in the hills of the Nilgiri plateau, with the sholas growing in valleys and grasslands covering the slopes.

In the southwest monsoon season of 2018, similar events of unusually high rainfall occurred over the highland districts of Idukki, Wayanad, and Coorg, causing hundreds of landslides. A predominant view was that this was primarily because of the indiscriminate construction of roads and proliferating concretization of the hills.

However, even within the highly stable shola-grassland ecology, a large number of landslides have occurred in spots with no apparent forms of disturbance such as roads and pathways cut through them. This signifies that climate-change has reached a level that is beyond the capacity of the ecosystem and land resilience.

What is causing the collapse of the last remaining wild spaces is the culmination of every action that has contributed to the climate crisis.

These actions invariably stem from places that have long lost their plant ecological cover—urban-industrial-agricultural complex. There is fatally no time to keep ignoring this primary cause. Even if we ignore this and look to safeguard the last remain wilderness areas from being deforested or `developed’, they are vulnerable to climate change-related destruction.

Threats closer to the last remaining ecological spaces must be also curtailed. For instance, despite the consecutive years of extreme precipitation over short periods, in the Nilgiri Biosphere region, there are hardly any steps being taken to address ecological security. Building regulations stand to get eased and road expansion works continue in full swing.

However, worryingly similar to what happened in the last two years when much of the annual rainfall was concentrated over a few days later in the monsoon period, this year too, 2020 has be no different. The onset of the monsoon was delayed, and large parts of peninsula experienced a significant deficiency well into the monsoon period. This year’s monsoon has brought intense, short bursts of extreme rainfall, not only in the Western Ghats regions and southern India, but all across the Indian subcontinent.

Destruction by dams and tunnels

Neela-Kurinji or Strobilanthes kunthiana flowering in the grassland habitats of the Nilgiris. This spectacle takes place only once in 12 years

The Kundha watershed region can be broadly divided into two sections – the higher slopes and the descending valleys. Hundreds of landslides occurred in both these sections, with shola-grassland ecology dominating in the higher slopes, and various types of land-uses such as tea cultivation, vegetable farming, villages and non-native tree plantations dominating the descending valleys. The descending valleys are also studded with several dams and hydroelectric structures.

The Kundha Hydro-Electric Power Scheme is one of the largest hydropower generating installations in Tamil Nadu-with 10 dams, several kilometers of underground tunnels, and a capacity of 585 MW. In addition to this, this system is now getting two more dams and a series of tunnels, to set up large  pumped storage hydropower facilities. The claim is to generate 1500 MW, of electricity during peak demand hours, but while using almost 1800 MW in the process.

With the level of destruction that extreme precipitation events are bringing to the Kundha watershed, it is disastrous to add more large dams and tunnels. The intensity of floods has turned so strong that even the largest dam complexes in the world, face threats of being breached.

An Aerides ringens orchid growing on a shola tree.


Safeguarding the last remaining zones of ecology and biodiversity from threats of direct destruction is crucial. Concurrently, the larger world-wide urban-industrial-agricultural complex, from where the climate crisis stems from needs drastic change. The constant incursions into more and more ecological spaces in the form of new dams, roads, and buildings, are also connected to this complex.

Whether it is the landslides in the grasslands of the high elevation plateaus in southern India; the melting glaciers of the Himalayas in northern India; the dying coral and rising sea levels elsewhere in the planet; the global coronavirus (Covid-19) pandemic that has brought about unimaginable changes – we have to understand the interconnectedness of these dire effects and learn from nature.

Godwin Vasanth Bosco is an ecologist working to restore shola and grassland ecology in the Nilgiri Biosphere. He is the author of the book Voice of a Sentient Highland on the Nilgiri Biosphere.

This piece was first published on Down to Earth. All the photographs were taken by the author himself.

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