Dey, R., Sharma, S.B. & Thakkar, M.G, ‘Maximising ecological value and assessing land suitability for sustainable grassland management in Asia’s largest tropical grassland, Western India’, Sci Rep 14, 13658 (2024). doi.org/10.1038/s41598-024-62775-9
Grasslands are one of the largest ecosystems in the world. They are distributed mainly in semiarid and arid areas, and include savannahs, grassy shrublands, and open grasslands. They harbour a large number of unique and iconic species and offer a variety of material and intangible advantages to people, including several ecosystem services such as carbon storage, climate mitigation, and pollination. Like other types of biodiversity, they face the problem of degradation due to deforestation, overgrazing, agriculture, urbanisation, and other natural and human-made reasons. As much as 49% of grassland areas worldwide are estimated to be experiencing degradation.
In India, grasslands account for approximately eight lakh sq. km, or about 24% of the country’s total land area (32.8 lakh sq. km). They are increasingly threatened by agricultural conversion, tree-based plantation projects, invasive species, and mega-development projects. The issue is exacerbated by the strong bias of government and non-profit organisations for the conservation and protection of forests.
The Kachchh district in Gujarat, in the western part of the country, houses one of the largest tracts of grasslands in the country. Popularly known as ‘Banni’, it once covered an area of approximately 3,800 sq. km but it has now decreased to about 2,600 sq. km. In a new study, researchers at the Department of Earth and Environmental Science in Krantiguru Shyamji Krishna Verma (KSKV) Kachchh University, in Bhuj, have assessed the suitability of different areas of Banni for sustainable grassland restoration, considering ecological value to be the primary criterion.
Findings of the study
They grouped the prospective restoration zones of the Banni grassland into five categories depending on how suitable each zone was for restoration. They have found that as much as 937 sq. km (or 36%) of the existing grassland area was “highly suitable”, 728 sq. km (28 %) was “suitable”, 714 sq. km (27%) was “moderately suitable”, 182 sq. km. (7%) was “marginally suitable”, and 61 sq. km (2%) was “not suitable” for restoration.
Speaking to this correspondent, assistant professor and leader of the study team Seema Bhargav Sharma said the first two categories of “highly suitable” and “suitable” zones — which accounted for nearly two-thirds of the complete Banni grasslands — can be restored easily by simply providing them with adequate water sources, either through irrigation or rainwater harvesting.
Grassland expansion should also not be much difficult in the third “moderately suitable” zone. Further, the “marginally suitable” and “not suitable” zones can also be managed through interventions such as terracing; with supplementary inputs like fertilizers; and by protecting from high water run-off and erosion, and salt intrusion, the researchers said.
The study could provide the National Green Tribunal (NGT) and policymakers a robust foundation for crafting policies aimed at protecting and rehabilitating degraded grasslands. “The detailed assessment of land suitability can inform legal and regulatory frameworks to ensure sustainable land use and conservation practices,” Dr. Sharma added. A key feature of the new study, she said, is that it provides a holistic assessment. The majority of research on grassland degradation has so far been performed only at the scale of sample plots. Some studies have been conducted at the regional scale but they also mainly used single vegetation indicators, such as net primary productivity (NPP) and the normalised difference vegetation index (NDVI), without accounting for the characteristics of the soil. This compromised the accuracy of suitability analysis and grassland degradation assessment, she said.
“Our study fills the gap and also covers more aspects to get as comprehensive a picture as possible. We have analysed multiple characteristics of soil also, such as the availability of the three important nutrients, nitrogen, phosphorus, and potassium, and four essential micronutrients, iron, manganese, zinc, and copper, … soil acidity, soil texture, soil organic carbon, salinity, the water holding capacity, cation exchange capacity, bulk density, and infiltration rate,” Dr. Sharma added. She also noted that the team used satellite data to check aspects such as land use and land cover, geomorphology, and land slope. “In all, 20 parameters were analysed,” she said. “The study aimed at not only assisting identification of lands suitable for grassland development but also to help manage them in a sustainable manner.”
Methodology and impact
The study was conducted across the area of the Banni grassland. The researchers collected soil samples from 45 locations, and data for geomorphological analyses. The satellites in question that provided data on slope, land use, and land cover were the U.S. Sentinel 2 satellite and the Advanced Spaceborne Thermal Emission and Reflection Radiometer (or ASTER).
Research scientist Rupak Dey, whose doctoral work resulted in the study, said, “Our research can help generate evidence-based recommendations for sustainable grassland management, including biodiversity conservation and the enhancement of livelihoods for local communities dependent on grasses for their livestock.”
The researchers’ findings were published in the journal Scientific Reports in June. Apart from Dr. Sharma and Dr. Dey, the study team consisted of Mahesh G.Thakkar, the director of the Lucknow-based Birbal Sahni Institute of Palaeosciences.
Himender Bharti, a member of the International Union for Conservation of Nature (IUCN) Commission on Ecosystem Management South Asia Regional Network, said the study was appropriate as it could help provide action plans to conserve grasslands, which have a vital role to play particularly in the context of climate change as they are a great source for sequestration of carbon dioxide. Dr. Bharti wasn’t involved in the research.
He also said that many bird species — such as the great Indian bustard and the Bengal florican — prefer to breed in grasslands, but grassland areas are shrinking constantly due to anthropogenic activities, threatening biodiversity as well as the ecosystem services they provide.
“There is an urgent need for government agencies and other stakeholders to make efforts to conserve them for the future generations,” he said.
P. Sunderarajan is a Delhi-based freelance science correspondent.
