The Eastern Himalayas extend from eastern Nepal across Northeast India, Bhutan, the Tibet Autonomous Region to Yunnan in China and northern Myanmar. The climate of this region is influenced by the monsoon of South Asia from June to September. [1] It is a biodiversity hotspot, with notable biocultural diversity. [2] [3]
The Eastern Himalayas has a more varied geomorphic history and pervasive topographic features than the Central Himalayas. In the southwest of the Sub-Himalayas lies the Singalila Ridge, the western end of a group of uplands in Nepal. Most of the Sub-Himalayas are in Nepal; a small portion reaches into Sikkim, India and a fragment is in the southern half of Bhutan. The region's topography, in part, has facilitated the region's rich biological diversity and ecosystem structure. [3]
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The Buxa range of Indo-Bhutan is also a part of the ancient rocks of the Himalayas. The ancient folds, running mainly along an east-west axis, were worn down during a long period of denudation lasting into cretaceous times, possibly over a hundred million years. During this time the carboniferous and permian rocks disappeared from the surface, except in its north near Hatisar in Bhutan and in the long trench extending from Jaldhaka River to Torsa River, where limestone and coal deposits are preserved in discontinuous basins. Limestone deposits also appear in Bhutan on the southern flanks of the Lower Himalayas. The rocks of the highlands are mainly sandstones of the Devonian age, with limestones and shales of the same period in places. The core of the mountain is exposed across the centre, where Paleozoic rocks, mainly Cambrian and Silurian slates and Takhstasang gneiss outcrops are visible in the northwest and northeast, the latter extending to western Arunachal Pradesh in India.
In the Mesozoic era the whole of the worn-down plateau was under sea. In this expansive shallow sea, which covered most of Assam and Bhutan, chalk deposits formed from seawater tides oscillating between land and sea levels. During subsequent periods, tertiary rocks were laid down. The Paro metamorphic belt may be found overlying Chasilakha-Soraya gneiss in some places. Silurian metamorphics in other places suggest long denudation of the surface. This was the time of Alpine mountain and large number of "active volcanoes" formation which act as backbone of the Himalayas and much of the movement in the palaeozoic region was probably connected with it. The Chomolhari tourmaline granites of Bhutan, stretching westwards from the Paro Chu and adds much depth below the present surface, were formed during this period of uplift, fracture and subsidence.
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The climate of the Eastern Himalayas is of a tropical montane ecosystem. The tropical rainforest climate is hot and wet all year round, with no dry season in the foothills in Köppen Climate Classification System (Af), and chilly winters mainly on higher elevations. The hot season commences around the middle of April reaching its maximum temperature in June, and finishing by the end of August. The average summer temperature is generally 20 °C (68 °F). The average annual rainfall is 10,000 mm (390 inches). A significantly large amount of snowfall is rare, and it is uncommon even at higher elevations. This belt of Himalayas is wetter as it receives more rain than the drier Western Himalayas.
In the valleys of Rangeet, Teesta, and Chumbi most precipitation during winter takes the form of snowfall. Snow accumulation in the valleys greatly reduces the area's wintertime temperature. The northeast monsoon is the predominant feature of the Eastern Himalayan region's weather, while on the southern slopes cold season precipitation is more important.
Agricultural conditions vary throughout the region. In the highlands the soil is morainic, and the hill slopes are cut by the locals into successive steps or terraces only a few meters broad, thus preventing water run-off and allowing spring crops to thrive. The region's economy relied mostly on shifting cultivation agriculture, supplemented by hunting, fishing and barter trade. Agricultural does not produce sufficient yields to meet local needs. The region's economy remained stagnant and at subsistence levels for centuries due to the lack of capital, investor access, or entrepreneurial knowledge. Inhabitants also relied heavily on wild and semi-cultivated species for food and herbal medicines. [2]
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The Eastern Himalayas consist of 6 distinct political/national territories:
The Eastern Himalayas sustain a diverse array of wildlife, including many rare species of fauna and flora. [3] Wildlife in Nepal includes snow leopard in its Himalayan region, and Indian rhinoceros, Asian elephant and water buffalo in the foothills of the Himalayas, making the country one of the world's greatest biodiversity hotspots. Three major river basins of Nepal, namely the Ghaghara, Gandaki River and Koshi River basins, feature dense forests and provide habitat for butterfly species and 8% of the world's bird species. Preserving this diverse wilderness is essential for the area's and the world's biodiversity. The area has many ecological projects intended to ensure the survival and growth of many species. [4]
The most diverse cloud forest is in India and China at 2,000–3,300 m (6,600–10,800 ft), and tropical rainforest on the lower slopes up to 900 m (3,000 ft) in the foothills. At higher elevations, wet páramo grasslands occur up to 4,500 m (14,800 ft), and above this elevation snow and ice occupies the space. Asian black bear, Himalayan vulture, and pikas are common at higher elevations, and also on the Tibetan plateau. Arunachal macaque (Macaca arunachalensis) and Rhesus macaque (M. mulatta) live in the tropical cloud forests, alongside various sunbird and pheasant species. Himalayan high-elevation wetlands are also notable for their biodiversity. [3]
Meconopsis gakyidiana is the national flower of Bhutan, commonly called the blue poppy. This flower was the source of an ecological mystery for nearly a century, due to its misclassification as Meconopsis grandis. In 2017, after three years of field work and taxonomic studies, its classification was corrected by Bhutanese and Japanese researchers. It was theorised this misclassification may have arisen due to the finding that some Himalayan flora readily hybridize with each other and produce viable seeds, causing wider morphological diversity. [5]
Kangchenjunga, also spelled Kanchenjunga, Kanchanjanghā and Khangchendzonga, is the third-highest mountain in the world. Its summit lies at 8,586 m (28,169 ft) in a section of the Himalayas, the Kangchenjunga Himal, which is bounded in the west by the Tamur River, in the north by the Lhonak River and Jongsang La, and in the east by the Teesta River. It lies in the border region between Koshi Province of Nepal and Sikkim state of India, with the two peaks West and Kangbachen in Nepal's Taplejung District and the other three peaks Main, Central and South directly on the border.
The Himalayas, or Himalaya is a mountain range in Asia, separating the plains of the Indian subcontinent from the Tibetan Plateau. The range has several peaks exceeding an elevation of 8,000 m (26,000 ft) including Mount Everest, the highest mountain on Earth. The mountain range runs for 2,400 km (1,500 mi) as an arc from west-northwest to east-southeast at the northern end of the Indian subcontinent.
Pleione is a small genus of predominantly terrestrial but sometimes epiphytic or lithophytic, miniature orchids. This genus is named after Pleione, mother of the Pleiades, and comprises about 20 species. Common names of this genus include peacock orchid, glory of the east, Himalayan crocus, Indian crocus and windowsill orchid. The genus DiploconchiumSchauer is generally included here. Pleione is abbreviated to Pln in trade journals.
Bhotiya or Bhot is an Indian and Nepali exonym lumping together various ethnic groups speaking Tibetic languages, as well as some groups speaking other Tibeto-Burman languages living in the Transhimalayan region that divides India from Tibet. The word Bhotiya comes from the classical Tibetan name for Tibet, བོད, bod. The Bhotiya speak numerous languages including Ladakhi, Drejongke, Yolmo and Sherpa. The Indian recognition of such language is Bhoti / Bhotia having Tibetan scripts and it lies in the Parliament of India to become one of the official languages through Eighth Schedule of the Indian Constitution.
The Himalayan subtropical pine forests are a large subtropical coniferous forest ecoregion covering portions of Bhutan, India, Nepal, and Pakistan.
Makalu Barun National Park is a national park in the Himalayas of Nepal that was established in 1992 as the eastern extension of Sagarmatha National Park. It is the world's only protected area with an elevation gain of more than 8,000 m (26,000 ft) enclosing tropical forest as well as snow-capped peaks. It covers an area of 1,500 km2 (580 sq mi) in the Solukhumbu and Sankhuwasabha districts, and is surrounded by a bufferzone to the south and southeast with an area of 830 km2 (320 sq mi).
Kyongnosla Alpine Sanctuary is a nature reserve in Gangtok district, Sikkim, India. It is situated around the area adjoining the Tsomgo (Changu) lake along the Nathula Road. Located about 31 km (19 mi) east of Gangtok, the capital of Sikkim, this sanctuary covers an area of about 31 km2 (12 sq mi), and extends from the "15th Mile" police check point up to and along the ridges bordering the Rong Chu Valley and Lake Tsomgo.
The Eastern Himalayan broadleaf forests is a temperate broadleaf forest ecoregion found in the middle elevations of the eastern Himalayas, including parts of Nepal, India, Bhutan, Myanmar and China. These forests have an outstanding richness of wildlife.
Wildlife diversity is a notable feature of Nepal. Because of the variance in climate, from tropical to arctic, Nepal has a large variety of plants and animals. Wildlife tourism is a major source of tourism in the country. There are some animal species which are unique to Nepal, such as the spiny babbler. Nepal is also host to many rhododendron species. Nepal has numerous national parks and reserves to protect its diverse fauna. Nepal is a biodiversity hot spot with ecoregions broadly comprising the mountainous ecoregion, the savanna and grasslands ecoregion of the terai (foothills), and the Rara Lake ecoregion.
Sessa Orchid Sanctuary is a 100 km2 protected area of India in the Himalayan foothills in Bhalukpong Forest Division of West Kameng District, Arunachal Pradesh. It conjoins Eaglenest Wildlife Sanctuary to the southwest. It is a part of the Kameng Protected Area Complex (KPAC), which is an Elephant Reserve. See map. The department of Environment & Forests has developed trekking routes for visitors to enjoy the natural habitats of orchids. There are deep gorges and valleys, high peaks and rugged terrain that are rewarding for nature lovers and adventure tourists. A nursery includes representative specimens of various orchid species of the sanctuary and a demonstration farm of Cymbidium hybrids for cut-flower production. Most of Sessa has traditionally been claimed by the Bugun tribe as part of their territory.
The Eastern Himalayan alpine shrub and meadows is a montane grasslands and shrublands ecoregion of Bhutan, China, India, Myanmar, and Nepal, which lies between the tree line and snow line in the eastern portion of the Himalaya Range.
The Northern Triangle temperate forests is a temperate broadleaf and mixed forest ecoregion of thick forest covering the mountains of northern Myanmar.
The Kingdom of Bhutan is a small, landlocked nation nestled in the southern slopes of the Eastern Himalaya. To its north lies the Tibet Autonomous Region of China and to the west, south and east lies the Indian states of Sikkim, Bengal, Assam and Arunachal Pradesh.
Uttarakhand has a total geographic area of 53,483 km2, of which 86% is mountainous and 65% is covered by forest. Most of the northern parts of the state are part of Greater Himalaya ranges, covered by the high Himalayan peaks and glaciers, while the lower foothills were densely forested till denuded by the British log merchants and later, after independence, by forest contractors. Recent efforts in reforestation, however, have been successful in restoring the situation to some extent. The unique Himalayan ecosystem plays host to many animals, plants and rare herbs. Two of India's great rivers, the Ganges and the Yamuna take birth in the glaciers of Uttarakhand, and are fed by myriad lakes, glacial melts and streams.
The Eastern Himalayan subalpine conifer forests is a temperate coniferous forests ecoregion which is found in the middle and upper elevations of the eastern Middle Himalayas, in western Nepal, Bhutan, northern Indian states including Arunachal Pradesh and Sikkim and adjacent Myanmar and China.
The ecology of the Himalayas varies with climate, rainfall, altitude, and soils. The climate ranges from tropical at the base of the mountains to permanent ice and snow at the highest elevations. The amount of yearly rainfall increases from west to east along the southern front of the range. This diversity of climate, altitude, rainfall and soil conditions supports a variety of distinct plant and animal species, such as the Nepal gray langur
Biogeographic classification of India is the division of India according to biogeographic characteristics. Biogeography is the study of the distribution of species (biology), organisms, and ecosystems in geographic space and through geological time. India has a rich heritage of natural diversity. India ranks fourth in Asia and tenth in the world amongst the top 17 mega-diverse countries in the world. India harbours nearly 11% of the world's floral diversity comprising over 17500 documented flowering plants, 6200 endemic species, 7500 medicinal plants and 246 globally threatened species in only 2.4% of world's land area. India is also home to four biodiversity hotspots—Andaman & Nicobar Islands, Eastern Himalaya, Indo-Burma region, and the Western Ghats. Hence the importance of biogeographical study of India's natural heritage.
The Sacred Himalayan Landscape is a 39,021 km2 (15,066 sq mi) large trans-boundary landscape in the eastern Himalayas encompassing temperate broadleaf and conifer forests, alpine meadows and grasslands, which harbour more than 80 mammal and more than 440 bird species. It extends from Nepal's Langtang National Park through Sikkim and Darjeeling in India to western Bhutan's Torsa Strict Nature Reserve. More than 73% of this landscape is located in Nepal, including Sagarmatha National Park, Makalu Barun National Park, and Kanchenjunga Conservation Area. About 24% is located in India, encompassing Khangchendzonga, Singalila and Neora Valley National Parks as well as Fambong Lho, Maenam, Senchal, Mahananda Wildlife Sanctuaries, Shingba and Barsey Rhododendron Sanctuaries and Kyongnosla Alpine Sanctuary.
Arunachal Pradesh is primarily a hilly tract nestled in the foothills of the Himalayas in northeast India. It is spread over an area of 83,743 km2 (32,333 sq mi). 98% of the geographical area is land out of which 80% is forest cover; 2% is water. River systems in the region, including those from the higher Himalayas and Patkoi and Arakan Ranges, eventually drain into the Brahmaputra River.
The geology of Bhutan is less well studied than many countries in Asia, together with the broader Eastern Himalayas region. Older Paleozoic and Precambrian rocks often appear mixed together with younger sediments due to the Himalayan orogeny.
