Wildlife Regions of India : North-East India

The North-East Indian region represents a globally unparalleled biogeographical junction where the Indo-Malayan, Palearctic, and Sino-Himalayan realms converge, creating a landscape of immense ecological complexity. Topographically, the region is highly diverse, encompassing the vast alluvial floodplains of the Brahmaputra and Barak river valleys, flanked by the sharply rising Eastern Himalayas to the north, the Meghalaya plateau to the south, and the Patkai, Naga, and Mizo hill ranges extending into Southeast Asia. The climate is defined by the intensely active tropical monsoon, which, combined with the region’s complex orography, results in some of the highest annual rainfall on Earth. This exceptional precipitation sustains a staggering array of vegetation types, ranging from immense tracts of tropical wet evergreen and semi-evergreen forests to extensive riverine grasslands, culminating in temperate broadleaf and alpine forests at higher elevations. The biodiversity here is exceptionally rich, serving as the evolutionary cradle for numerous primitive angiosperms and harboring a high concentration of restricted-range endemic fauna, particularly among amphibians, avifauna, and primates. Ecologically, the region acts as a vital dispersal corridor connecting the Indian subcontinent with Southeast Asia. However, this fragile landscape faces relentless conservation challenges, including extensive habitat loss driven by traditional shifting agriculture (jhum), the expansion of oil palm and tea plantations, widespread poaching, and the development of massive hydro-electric infrastructure that threatens riparian continuity. Within this rapidly changing frontier, Biosphere Reserves act as critical strongholds. They are essential for protecting the last remaining contiguous tracts of primary forest, safeguarding critical transboundary wildlife corridors, preventing the extinction of highly specialized endemic species, and harmonizing conservation efforts with the deep-rooted cultural practices of diverse indigenous communities who have shaped these landscapes for millennia.

Manas Biosphere Reserve

Located in the foothills of the Eastern Himalayas in Assam, the Manas Biosphere Reserve encompasses a highly dynamic landscape of dense forests and alluvial plains spanning the Bhabar and Terai tracts. Situated at altitudes ranging from 50 to 200 meters, the reserve experiences a tropical monsoon climate that sustains a mosaic of major ecosystems, including tropical semi-evergreen forests, moist deciduous forests, and extensive, flood-maintained riverine grasslands. The ecosystem is fundamentally shaped by the Manas River, a major tributary of the Brahmaputra, which creates crucial wetland habitats. This rich environment supports an extraordinary diversity of flagship mammals, notably the Bengal Tiger, Asian Elephant, Greater One-horned Rhinoceros, Clouded Leopard, and Asiatic Water Buffalo. Manas is globally renowned for its critical population of highly threatened endemics, including the Pygmy Hog, Hispid Hare, Golden Langur, and the Bengal Florican, alongside significant reptile species like the endemic Assam Roofed Turtle. The landscape is historically inhabited by the indigenous Bodo communities, whose involvement is increasingly central to modern conservation strategies. Inducted into the UNESCO MAB network in 2001, Manas holds profound ecological significance as a refuge for specialized grassland endemics, a benchmark for successful wildlife population recovery following historical civil unrest, and a critical component of international transboundary conservation efforts.

Landscape Connectivity

The Manas Biosphere Reserve anchors one of the most critical transboundary conservation landscapes in Asia, functioning as a vital contiguous habitat spanning the Indo-Bhutan border. Its core zone, the Manas National Park (also a designated Tiger Reserve and UNESCO World Heritage Site), merges seamlessly with the Royal Manas National Park in Bhutan to the north. This unbroken international forest block is absolutely indispensable for the unrestricted seasonal migration of Asian Elephants, Bengal Tigers, and Clouded Leopards across the Himalayan foothills. To the west, the landscape maintains vital, though fragmented, ecological linkages with the Buxa Tiger Reserve in West Bengal via the Ripu-Chirang reserved forests, forming the expansive Manas-Buxa-Gorumara wildlife corridor. Protecting this larger landscape continuity is critical for maintaining the genetic diversity of megafauna and preserving the hydrological integrity of the Manas river basin.

Dibru-Saikhowa Biosphere Reserve

Situated in the floodplain of the Brahmaputra river in the Tinsukia and Dibrugarh districts of Assam, the Dibru-Saikhowa Biosphere Reserve is a highly dynamic riverine landscape defined by shifting river channels and seasonal inundation. Resting at a low elevation of approximately 110 to 120 meters, the region is subjected to a humid, tropical monsoon climate. This distinct hydrology fosters unique major ecosystems, primarily consisting of moist mixed semi-evergreen forests, moist deciduous forests, extensive alluvial grasslands, and the largest expanse of Salix (willow) swamp forests in north-eastern India. The reserve is bounded and intersected by the Brahmaputra, Lohit, and Dibru rivers, creating a complex network of wetlands and channels. The landscape harbors significant fauna, including the Asian Elephant, Bengal Tiger, Hoolock Gibbon, and Capped Langur, while the rivers support the endangered Ganges River Dolphin. Avian diversity is exceptional, making it a critical refuge for the globally threatened White-winged Wood Duck and the Jerdon’s Babbler. The reserve is also uniquely known for its population of feral horses, descended from cavalry stock abandoned during World War II. Inhabited by indigenous communities such as the Mising and Moran, the reserve is ecologically vital for protecting specialized riverine swamp ecosystems, studying flood-pulse dynamics, and conserving crucial staging grounds for migratory avifauna within the Brahmaputra valley.

Landscape Connectivity

The Dibru-Saikhowa Biosphere Reserve functions as a critical riparian refuge within the heavily altered landscape of the upper Brahmaputra valley. Its core, the Dibru-Saikhowa National Park, is fundamentally shaped by riverine dynamics, relying on the extensive water network for ecological connectivity rather than traditional terrestrial forest corridors. Across the Brahmaputra to the north, the reserve maintains a vital ecological relationship with the D’Ering Memorial Wildlife Sanctuary in Arunachal Pradesh, facilitating the seasonal movement of Asian Elephants and serving as a contiguous corridor for migratory waterfowl and Gangetic Dolphins. To the south, although heavily fragmented by tea estates and human settlements, tenuous historical linkages exist with the Dehing Patkai National Park, allowing for limited dispersal of arboreal primates and large carnivores. Securing these riparian and stepping-stone corridors is essential to prevent the islandization of Dibru-Saikhowa amidst rapidly expanding river infrastructure and agriculture.

Dihang-Dibang Biosphere Reserve

Located in the rugged, inaccessible mountainous terrain of Arunachal Pradesh, the Dihang-Dibang Biosphere Reserve is a landscape of staggering topographical immensity, encompassing the deep gorges of the Siang and Dibang rivers. Spanning a monumental altitudinal gradient from approximately 500 meters to over 6,000 meters, the climate shifts radically from tropical warmth in the deep river valleys to harsh alpine conditions on the glaciated peaks. This extreme variation supports highly diverse ecosystems, transitioning rapidly from sub-tropical broadleaf forests through dense temperate coniferous forests, impenetrable rhododendron scrubs, and ultimately to alpine meadows and permanent snowfields. The pristine, fast-flowing Siang (Dihang) and Dibang rivers dictate the region’s hydrology and microclimates. The reserve provides critical refuge for elusive, high-altitude flagship fauna, including the Mishmi Takin, Red Goral, Snow Leopard, Clouded Leopard, and Bengal Tiger, which exhibits a remarkable altitudinal adaptability here. The avian richness is highlighted by rare endemics such as Sclater’s Monal and Blyth’s Tragopan. Deeply tied to the cultural heritage of the indigenous Adi and Mishmi tribes, who possess profound knowledge of the challenging terrain, the reserve is of immense ecological significance. It acts as an invaluable, largely unstudied natural laboratory for understanding altitudinal species distribution, protecting vast undisturbed watersheds, and safeguarding palearctic and Indo-Malayan lineages in a pristine frontier landscape.

Landscape Connectivity

The Dihang-Dibang Biosphere Reserve constitutes one of the most extensive and least disturbed continuous forest blocks remaining in Asia, acting as a massive biological corridor linking the Indian Himalayas with the mountainous frontiers of Tibet and Myanmar. The reserve’s core consists of the Mouling National Park and the Dibang Wildlife Sanctuary. This expansive landscape ensures unbroken altitudinal connectivity, allowing species like the Mishmi Takin and Snow Leopard to migrate seasonally without encountering human infrastructure. Crucially, the reserve integrates with massive tracts of unclassed state forests and community-managed lands, extending ecological continuity eastward towards the Namdapha Tiger Reserve. Internationally, it shares remote, contiguous alpine and temperate forest borders with the Tibet Autonomous Region (China) and Myanmar, forming a colossal transboundary wilderness that is vital for the genetic resilience of high-altitude megafauna and the protection of the Brahmaputra’s primary headwaters.

Nokrek Biosphere Reserve

Situated in the Garo Hills of Meghalaya, the Nokrek Biosphere Reserve encompasses a rugged, highly weathered ancient plateau landscape centered around the Nokrek peak. Ranging in altitude up to 1,412 meters, the region experiences a highly humid, tropical monsoon climate, receiving some of the highest rainfall in the world. This intense precipitation sustains remarkably dense, layered tropical evergreen and semi-evergreen forests, alongside moist deciduous tracts and localized patches of unique climax vegetation. The reserve forms the crucial catchment for the Simsang River and numerous smaller streams that carve deep valleys through the limestone and sandstone terrain. Nokrek is a critical stronghold for highly threatened primates, notably the Western Hoolock Gibbon, Pig-tailed Macaque, and Stump-tailed Macaque, alongside flagship mammals like the Asian Elephant and Clouded Leopard. The floral diversity is globally significant, as the reserve is the primary sanctuary for the Indian wild citrus (Citrus indica, locally known as Memang Narang), a critically important genetic ancestor of modern cultivated citrus fruits. Deeply integrated with the matrilineal Garo indigenous communities, who practice complex traditional land management, the reserve was inducted into the UNESCO MAB network in 2009. Nokrek is of unparalleled conservation importance for protecting ancient botanical gene pools, sustaining highly restricted primate populations, and preserving the intricate subterranean limestone cave ecosystems and their associated endemic fauna.

Landscape Connectivity

The Nokrek Biosphere Reserve functions as the critical western anchor of the expansive Garo Hills Elephant Reserve, securing a vital conservation landscape across the Meghalaya plateau. Its core, the Nokrek National Park, relies on a highly sensitive network of forested ridges, community-owned lands (A’khing), and riparian corridors to maintain connectivity with the Balpakram National Park to the southeast and the Siju Wildlife Sanctuary to the east. This Nokrek-Balpakram landscape is considered one of the most important remaining elephant corridors in northeastern India, facilitating crucial seasonal migrations. Furthermore, the region maintains vital watershed connectivity, as the protected forests ensure the hydrological stability of the Simsang River, which supports extensive downstream ecosystems extending into the plains of Bangladesh. Preventing the fragmentation of these community-forest corridors by coal mining and shifting cultivation is imperative for the survival of the region’s megafauna.

Regional Summary Table: North-East India