Salient Features of the Eastern Himalayas 1. Geographical Extent and Area The Eastern Himalayas span approximately 524,190 square kilometers. This region extends eastward from Central Nepal's Koshi Valley to northwest Yunnan in China, encompassing: Southeast Tibet, Bhutan, Parts of India: notably Sikkim, the Darjeeling hills of West Bengal, and the Arunachal Himalaya, Northern Myanmar. 2. Population and Settlement Patterns The region is home to about 38 million people, with a population density of 151 persons per square kilometer. 85% of the population resides in rural areas, primarily in the plains and valleys, which are more conducive to habitation than the rugged mountains. The region maintains a delicate balance between human settlements and natural ecosystems. 3. Ecotourism and Ecological Significance The Eastern Himalayas are a noted ecotourism hotspot, attracting visitors seeking refuge from Asia's dense urban centers. Ecotourism here is driven by the region's exceptional biodiversity, scenic landscapes, and ethnic diversity. Highland ecosystems offer a unique opportunity for conservation-based tourism. 4. Floral Diversity and Endemism The Eastern Himalayas are part of the Himalayan Biodiversity Hotspot, characterized by: Over 10,000 species of plants, with temperate broadleaved forests supporting some of the richest alpine flora on Earth. 71 genera and 3,160 species are endemic, including numerous species from the Rhododendron genus.India harbors at least 7,500 flowering plant species, and 50% of them are concentrated in this region—earning it the title "Cradle of Flowering Plants". 700+ species of orchids are found in Northeast India; Arunachal Pradesh alone harbors 545 species within 122 genera. Of these, 12 are endangered, 16 vulnerable, and 31 near threatened. Rare and threatened plant species include: Nepenthes khasiana (a pitcher plant) Tetracentron sinense (a relict tree species found in temperate deciduous forests) 5. Faunal Richness The Eastern Himalayas are home to a diverse range of faunal species: 300 mammalian species, 977 avian species, 176 reptilian species, 105 amphibian species,269 freshwater fish species Notable mammals include: Langurs, sloth bears, wild dogs, gaur, muntjacs, Snow leopards, Asian black bears, Himalayan tahr, Red panda, takin, and blue sheep Endemic and threatened mammals: Golden langur, Hispid hare, Pygmy hog, Namdapha flying squirrel (exclusive to the Namdapha National Park in Arunachal Pradesh), Snow leopard—elusive and adapted to high-altitude, rugged terrain 6. Special Reference to Arunachal Pradesh i. Geographical Setting: Arunachal Pradesh occupies a strategic position in the Eastern Himalayas, forming the easternmost extension of the Indian Himalayan region. It shares borders with three countries—Bhutan (west), China/Tibet (north and northeast), and Myanmar (east)—making it geopolitically sensitive andenvironmentally significant. Physiography: Dominated by steep mountainous terrain, with the Himalayan range running northwest to southeast. The region is dissected by major rivers such as the Siang (upper Brahmaputra), Subansiri, Kameng, Dibang, and Lohit, forming dynamic fluvial landscapes. Altitudinal Range: Elevation varies from as low as 100 meters in the foothill plains to over 7,000 meters in the high Himalayan ranges near the Tibetan frontier (e.g., Kangto Peak). This altitudinal diversity leads to a range of ecosystems and ecological transitions within a compact area. ii. Ecological and Bioclimatic Diversity Arunachal Pradesh is characterized by remarkable ecological stratification: Vertical Zonation of Vegetation: Tropical forests (below 1,000 m): Sal, bamboo, and evergreen rainforests. Subtropical forests (1,000—2,000 m): Oak, chestnut, and rhododendron. Temperate forests (2,000-3,000 m): Conifers like blue pine and spruce. Alpine meadows (above 3,500 m): Dwarf shrubs, grasses, and snow-covered pastures. Climatic Variability: Receives very high rainfall (up to 5,000 mm/year) in certain regions due to the influence of the Bay of Bengal monsoon. Winter snow in higher reaches and humid tropical summers in the valleys result in microclimatic pockets that support unique species.iii. Biodiversity Richness Arunachal Pradesh is one of the richest biodiversity zones in India, contributing significantly to the Eastern Himalayan Biodiversity Hotspot: Floral Diversity: Over 6,000 plant species including 500+ orchid species (many endemic and endangered). Contains unique medicinal plants like Taxus baccata (Himalayan yew) used in cancer treatment. Faunal Diversity: Habitat to over 750 bird species and 200+ mammal species. Endangered species include: Red Panda, Snow Leopard, Mishmi Takin, Clouded Leopard. Endemics like the Arunachal Macaque and Namdapha Flying Squirrel. Key Protected Areas: Namdapha National Park: Only national park in India that shelters four large cats—tiger, leopard, snow leopard, and clouded leopard. Mouling National Park: Known for subtropical to alpine transitions. Pakke Tiger Reserve: Rich in hornbills and community-led conservation success. iv. Indigenous Communities and Ethnic Diversity Arunachal Pradesh’s human ecology is closely intertwined with its environment: Tribal Composition: Home to 26 major tribes and over 100 sub-tribes, including the Apatani, Adi, Nyishi, Monpa, Mishmi, and Galo. Each tribe has distinct language, attire, festivals, and ecological practices. Traditional Land Use:Widespread practice of shifting cultivation (jhum) in uplands, now transitioning to terraced or settled agriculture in some areas. Sustainable practices like sacred groves, community hunting bans, and ritual forest area. Rich knowledge of medicinal plants, wild edibles, and forest management passed through generations. Many tribes consider mountains, rivers, and groves as sacred, contributing to natural conservation. v. Environmental and Climate Stress The state's ecosystems are under increasing pressure due to both natural and human-induced factors: Anthropogenic Pressures: Deforestation due to agriculture, logging, and infrastructural development. Construction of roads and dams has led to habitat fragmentation and landslide-prone zones. Climatic Vulnerability: Evidence of glacier retreat in high ranges and altered monsoon patterns affecting water availability. Flooding and riverbank erosion during high-intensity rainfall events (notably along the Siang River). Seasonal water scarcity in uplands due to drying springs and erratic rainfall. vi. Policy and Planning Interventions Climate Adaptation Initiatives: Part of the Indian Himalayas Climate Adaptation Programme (IHCAP). Supported by national and international research bodies including ICIMOD, WWF India, and GB Pant Institute. Government support for bamboo-based industries, handloom weaving, and organic farming.