Context:
A recent global study published in the Proceedings of the National Academy of Sciences (PNAS) found that ancient or old-growth grasslands may not regain their original plant communities even after a century of recovery. The study highlights the ecological importance of conserving existing grasslands rather than assuming that they can simply be recreated after destruction.
What are Ancient Grasslands?
Ancient grasslands are ecosystems that have developed over long periods and are dominated by grasses and other non-woody herbaceous plants. They support rich biodiversity, provide grazing resources and pastoral livelihoods, prevent soil erosion and contribute significantly to terrestrial carbon storage. Despite this, grasslands have historically received less conservation attention than forests and are often classified as “wastelands”, making them vulnerable to agriculture, infrastructure, mining, plantations and energy projects.
Key Findings of the Study
Researchers analysed traits of 742 plant species from 24 studies across six continents, comparing species associated with old-growth and secondary grasslands. Secondary grasslands generally had fewer characteristic old-growth species and were dominated by taller plants with higher specific leaf area, greater leaf nitrogen and lower dry-matter content. These differences persisted for more than a century, indicating that vegetation recovery does not necessarily restore the original ecosystem.
Why Recovery is Difficult?
Destruction can alter soil nutrients, pH and microbial conditions, making the environment unsuitable for the original grassland flora. Native perennial grasses and forbs may therefore be replaced by weedy or non-native species. Old-growth grasslands also develop through long-term ecological processes such as periodic fire, herbivore grazing and seasonal climatic variation, which cannot always be recreated quickly.
Old-Growth vs Secondary Grasslands
Old-growth grasslands contain species adapted to long-standing ecological conditions and natural disturbance regimes. Secondary grasslands, formed after disturbance, may regain vegetation cover but often have altered species composition and ecological functions. Earlier research has similarly found that secondary grasslands can support substantially fewer plant species and may require centuries or longer to regain former richness.
Significance for India
India's grasslands occur across the Thar, Kutch, Deccan, Terai and Assam floodplains and support specialised wildlife. Grassland restoration has benefited species such as the Great Indian Bustard, Lesser Florican and Pygmy Hog. The GIB particularly demonstrates the importance of conserving entire grassland habitats rather than focusing only on individual species.
Major Policy Concern
A major challenge is the wasteland approach, under which naturally open ecosystems may be considered degraded land suitable for afforestation. However, planting trees on natural grasslands can alter habitat structure and threaten species adapted to open ecosystems. Recent research also shows that global land-use pressure increasingly affects natural non-forest ecosystems, highlighting the need to expand conservation beyond forests.
Classification of World Grasslands:
Grasslands are broadly classified into tropical and temperate grasslands. Tropical grasslands or savannas have warm conditions, distinct wet and dry seasons and generally 50–130 cm rainfall. Major examples include African Savannas, Llanos of Venezuela-Colombia and Campos of Brazil-Uruguay. Temperate grasslands experience hot summers and cold winters, generally receiving 25–75 cm rainfall. Important examples include Prairies of North America, Steppes of Eurasia, Pampas of Argentina-Uruguay, Velds of South Africa, Downs of Australia and Puszta of Hungary.
Way Forward:
India needs a dedicated National Grassland Restoration Programme alongside a National Grazing Policy. Priorities should include mapping and protecting old-growth grasslands, preventing inappropriate land conversion, controlling invasive species, promoting native-species restoration, managing grazing scientifically and involving pastoral communities.
