Terai-Duar savanna and grasslands

• Category: Grasslands, Tundra, and Human Biomes.
• Geographic Location: Asia.
• Summary: Poverty and international tensions are preventing conservation efforts across this haven for rare species and the tallest grass type in the world.

The Terai–Duar savanna and grasslands ecoregion is a narrow belt of marshy grasslands, savannas, open woodlands, and forests stretching south of the Himalayan foothills. It covers parts of Nepal, India, Bhutan, and Bangladesh, and extends 21,437 square miles (34,500 square kilometers) along the southern foothills of the Himalayas, from the Brahmaputra River in the east to the Yamuna River in the west.

Biodiversity

The Terai–Duar savanna and grasslands are a globally significant ecoregion for its rich biodiversity. The main features are its highly productive alluvial tall grassland, particularly for one of the tallest grasses in the world, species of Saccharum, which attain heights of 9–13 feet (3–4 meters). The ecoregion is also unique due to its nine distinct plant assemblages and eight succession phases.

This biome is a habitat of globally threatened species such as tiger (Panthera tigris), Asian elephant (Elephas maximus), greater one-horned rhinoceros (Rhinoceros unicornis), and swamp deer (Cervus duvauceli). Endangered medium-sized mammals such as the hispid hare (Caprolagus hispidus) and the pygmy hog (Porcula salvania) survive in a few locations in Assam, particularly around Manas National Park.

Threats and Conservation

Due to disturbances caused by human activity, this unique ecoregion is highly threatened. The grassland and forest areas have largely been converted to agricultural use. The Terai–Duar savanna and grasslands ecoregion mostly remains within protected areas. The protected area system includes: Koshi Tappu Wildlife Reserve, Chitwan National Park, Parsa National Park, Bardiya National Park, and Shuklaphanta National Park, all in Nepal; and Manas, Dudhwa, Katarniaghat, Mahananda, Buxa, and Gorumara wildlife reserves and national parks in India.

The degradation of the Terai–Duar savanna and grasslands ecoregion is causing great loss to biological diversity. The major causes of the loss include habitat alteration, overharvesting, species and disease introduction, pollution, and climate change. Associated issues include poverty, exploitation of the environment by the wealthy, real estate development and lack of infrastructure, rural overpopulation, and shrinking rural populations in some areas, traditional slash-and-burn agriculture, and modern commercial agricultural production. Many of these pressures lead to habitat damage and biodiversity loss.

While irrigation projects and water diversion systems such as the damming of local rivers are degrading and undermining the unprotected areas of grassland habitat here, even protected sections of the Terai–Duar savanna and grasslands ecoregion are facing the problems of poaching and some overgrazing. Studies of the Terai–Duars grasslands have also documented conversion of some grassland areas to woodland through woody encroachment, adding to pressure on grassland-dependent species. In 2020, researchers found that many animal populations in the region were declining due to human activity.

Government authorities of each country are combating each of these stressors in different ways and to varying degrees. In addition, there are several programs managed by international organizations. India and Nepal are serious about cooperating in managing this very important ecosystem and the protected areas; they have joined in various joint projects initiated by the World Wide Fund for Nature (WWF), such as the Sacred Himalayan Landscape and the Terai Arc Landscape Project. However, this ecoregion has weak conservation mechanisms overall. The generally weak conservation output is due to the scarcity of resources and to various types of civil and political conflicts in the region. With this backdrop, the conflict in natural resource utilization is seen as a normal and day-to-day problem across this ecoregion. For better management, more collaborative efforts are needed.

Bibliography

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Wikramanayake, Eric, and Gokarna Jung Thapa. “The Terai-Duar Savannas and Grasslands Ecoregion: Imperiled Himalayan Ecosystems.” Imperiled: The Encyclopedia of Conservation, 2002, pp. 228–42, doi:10.1016/B978-0-12-821139-7.00010-6. Accessed 11 Mar. 2026.