Terai-Duar savanna and grasslands
The Terai-Duar savanna and grasslands comprise a diverse ecoregion located south of the Himalayan foothills, spanning parts of Nepal, India, Bhutan, and Bangladesh. Covering approximately 21,437 square miles (34,500 square kilometers), this biome features marshy grasslands, savannas, and open woodlands. The area is renowned for its rich biodiversity, hosting globally threatened species such as the Bengal tiger, Asian elephant, greater one-horned rhinoceros, and swamp deer, alongside unique plant assemblages and tall grasses like Saccharum, which can grow up to 13 feet (4 meters) tall.
Despite its ecological significance, the Terai-Duar savanna is facing severe threats due to human activities, including agricultural expansion, habitat alteration, and pollution. Protected areas exist within this ecoregion, such as Chitwan National Park and Koshi Tappu Wildlife Reserve, yet challenges persist due to poaching, overgrazing, and weak conservation measures exacerbated by political and resource constraints. Collaborative management efforts between India and Nepal, supported by international organizations like the World Wildlife Fund, aim to enhance conservation strategies. However, ongoing conflicts over natural resource utilization present significant hurdles in preserving this vital ecosystem.
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Subject Terms
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 Grassland biome 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) from the Brahmaputra River in the east to the Yamuna River in the west.
Biodiversity
The Terai-Duar savanna grassland is 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 of the world, Saccharum, which attains heights of 9–13 feet (3–4 meters). The biome 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 pygmy hog (Porcula salvania) are found here, as well.
Threats and Conservation
Due to disturbances caused by human activity, this unique ecoregion is highly threatened. The grassland and forest areas have in large degree been converted to agricultural use. The Terai-Duar savanna grassland mostly remains only within protected areas. The protected system includes: Koshi Tappu Wildlife Reserve, Chitwan National Park, Parsa Wildlife Reserve, Bardia National Park, and Shukla Phanta Wildlife Reserve, all in Nepal; and Manas, Dudhwa, Katarniaghat, Mahananda, Buxa, and Garumara Wildlife Reserves and National Parks in India.
The degradation of the Terai-Duar savanna grassland is causing great loss to biological diversity. The major causes of the loss include habitat alteration, over-harvesting, species and disease introduction, pollution, and climate change. Associated issues include poverty, exploitation of the environment by the wealthy, real estate development and infrastructure underdevelopment, rural over-population—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 grassland are facing the problems of poaching and some overgrazing. By 2020, researchers found that almost all the region’s animal species were in decline 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 Wildlife Fund (WWF) such as 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
Johnsingh A. J. T., K. Ramesh, Q. Qureshi, et al. Conservation Status of Tiger and Associated Species in the Terai Arc Landscape, India. Dehra Dun: Wildlife Institute of India, 2004.
MacKinnon, J. Protected Areas Systems Review of the Indo-Malayan Realm. Cambridge, UK: World Bank, 1997.
Olson, David M. and Eric Dinerstein. “The Global 200: A Representation Approach to Conserving the Earth’s Most Biologically Valuable Ecoregions.” Conservation Biology 12, no. 3 (1998).
Rodgers, W. A. and H. S. Panwar. Planning Wildlife Protected Areas Network in India, Vols. 1–2. Dehra Dun, India: Department of Environment, Forests, and Wildlife, 1988.
Wikramanayake, E. D., C. Carpenter, H. Strand, and M. Mcknight, eds. Ecoregion-Based Conservation in the Eastern Himalaya, Identifying Important Areas for Biodiversity Conservation. Washington DC: WWF and Center for Integrated Mountain Development, 2004.
Wikramanayake, Eric, and Gokarna Jung Thapa. “The Terai-Duar Savannas and Grasslands Ecoregion: Imperiled Himalayan Ecosystems.” Reference Module in Earth Systems and Environmental Sciences, doi:10.1016/B978-0-12-821139-7.00010-6. Accessed 30 Aug. 2022.