India's grasslands in peril

Agriculture, tree plantations, invasive species and ill-informed policies threaten the country's savannas and pastoral livelihoods, writes Spoorthy Raman.

From the lofty Himalayas to the montane Shola forests of the Western Ghats, from the arid Thar Desert to the fertile floodplains in the east, grasslands once covered nearly two-thirds of India. An understory of grass dominates these landscapes, while woody plants lie scattered in the mix.

India’s grasslands are treasure troves of biodiversity, harbouring anywhere between 260 and 500 endemic species—nearly half of which scientists discovered in the last twenty years. Rare birds like the Great Indian bustard, swamp grass babbler, and animals like one-horned rhinoceros and swamp deer live here. These landscapes support pastoral communities that graze their livestock.

Destruction of grasslands

Grasslands store nearly 34% of the world’s carbon. However, in the last two centuries, the need to expand agriculture, an increased focus on planting trees, invasive species, and clean-energy initiatives have threatened grassland ecosystems across the country. 

In a recent study, researchers have found that these activities destroy and degrade grasslands, decimate native plant species, reduce plant diversity and increase the number of invasive species. Tilling the land damages the underground buds of grasses, which then fail to grow back. The dense tree cover in plantations blocks sunlight necessary for grass in the understory. Invasive plants outcompete native grasses.

Once lost, these species fail to recover and regrow even after agricultural operations cease or plantations are cut down. The study, published in the Journal of Ecology, suggests that India must protect its remaining ancient grasslands to conserve biodiversity.

“At least two-thirds of India is a savanna, yet we don’t know what such destructive land use means for native biodiversity,” says lead author Ashish Nerlekar from Texas A&M University, USA. “This study was motivated by the need to contribute to this knowledge gap.” 

The researchers conducted their study across seven districts in western Maharashtra, which lie in the rain shadow region of the Western Ghats. They selected 60 study sites—15 with old-growth savanna grasslands, farmlands, tree plantations and fallow land. Crops such as millets, pigeon peas, corn, sugarcane and cotton—all needing soil tilling—were grown on farmlands.

Tree plantations included exotic trees, such as Mexican lilac (Gliricidia sepium), Tasmanian blue gum (Eucalyptus globulus), neem and Siamese cassia (Cassia siamea). In each of the study sites, the researchers sampled different species of plants growing there, estimated the species richness, and identified the native and invasive plants.

The study found a steep decline in plant species growing in altered landscapes compared to old-growth savannas, with agricultural lands recording the least. Tillage agricultural land also had the fewest native plants—covering only 4% of the land—while native plants covered nearly half of the old-growth grasslands. On the other hand, tree plantations and fallow lands contained most of the invasive species, including cobbler’s peg (Bidens pilosa), parthenium, jute mallow and devil’s horsewhip (Achyranthes aspera).

Agriculture had altered the landscape so much that the plant community looked drastically different from what one finds in a grassland. Just 0.1% of farmlands were covered with native perennial grasses. The old-growth savanna patches supported 65 species not found in any of the three land types and contained 21 indicator species—demonstrating their value for conservation.

Although the researchers conducted the study in Maharashtra, Nerlekar says the findings hold good elsewhere, too. “Agriculture and tree plantations are not just a threat to Maharashtra’s savannas, but to all global savannas,” he says. 

“A strength of this study is that the authors have quantified this across a very broad rainfall gradient (~450–2000 mm) spanning the range from arid to mesic savannas,” says ecologist Mahesh Sankaran from the National Centre for Biological Sciences, Bengaluru, who was not involved in the study. “They have identified which native species are at risk from land conversion to agriculture and tree plantations.” 

Wastelands to grasslands

Although India’s grasslands have thrived for millions of years, the British colonial policies were a turning point for their future.

“I think one of the biggest threats to grasslands in India is the way they are classified. With a still-prevalent colonial classification as ‘wastelands’, grasslands are rapidly converted to other land-use types,” says ecologist Sutirtha Lahiri from the University of Minnesota, USA, who has studied Indian grasslands.

With labels such as ‘wastelands’ or ‘degraded forests’, the British policies let agriculture, tree plantations, afforestation efforts and other developmental projects reclaim them—a practice that has continued to this day. While India’s forest cover has seen some gains in recent years, its grasslands have shrunk by more than 30% between 2005-2015.

Many recent restoration policies and clean-energy initiatives like windmill farms increasingly target grasslands in India, further imperilling their existence. For example, India has pledged to restore 26 million hectares of land by 2030 under the Bonn Challenge—a global initiative to bring 350 million hectares of degraded land into restoration by 2030. However, a 2021 study found that many of the identified areas for restoration were grasslands, including the Terai in northern India.  

“Planting trees is not the only solution to the climate and biodiversity crises, and one has to be very careful in understanding what restoration means for different ecosystems,” says Nerlekar. He warns that authorities must plan restoration efforts carefully, especially for ecosystems like the Indian savanna.

“Due to our forest bias, grasslands have been systematically understudied, and we need to change that. Effective conservation will only come when we have the evidence to back it up,” adds Lahiri.