Ajay Kumar at 13:04, 31 August 2023

2023-08-31T13:04:00Z

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{{Short description|Eastern half of the Himalayas mountain range}}
[[File:Wiki_eastern_himalayas.jpg|alt=A political/geographical representation of the Eastern Himalayas (credits: ICIMOD)|thumb|340x340px|A political/geographical representation of the Eastern Himalayas. Image credits: [http://www.icimod.org/?q=3598 ICIMOD]]]

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.<ref>{{cite book |last1=Shrestha |first1=A.B. |last2=Devkota |first2=L.P. |date=2010 |title=Climate change in the Eastern Himalayas: observed trends and model projections |publisher=International Centre for Integrated Mountain Development |location=Kathmandu, Nepal |url=http://lib.icimod.org/record/26846/files/attachment_697.pdf}}</ref> It is a [[biodiversity hotspot]], with notable [[biocultural diversity]].<ref name="O'Neill_al2017">{{cite journal |last1=O'Neill |first1=A.R.|last2=Badola |first2=H.K. |last3=Dhyani |first3=P.P. |last4=Rana |first4=S.K. |date=2017 |title=Integrating ethnobiological knowledge into biodiversity conservation in the Eastern Himalayas |journal=Journal of Ethnobiology and Ethnomedicine |volume=13 |issue=1 |pages=21 |doi=10.1186/s13002-017-0148-9 |pmid=28356115 |pmc=5372287}}</ref><ref name="O'Neill_2019"/>

==Geologic strata==
The Eastern [[Himalayas]] has a more varied geomorphic history and pervasive topographic features than the Central Himalayas. In the southwest of the [[Sub-Himalayan Range|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.<ref name="O'Neill_2019">{{cite journal |last1=O'Neill |first1=A. R.| date=2019 |title=Evaluating high-altitude Ramsar wetlands in the Sikkim Eastern Himalayas |journal=Global Ecology and Conservation |volume=20 |page=e00715 |doi=10.1016/j.gecco.2019.e00715 |doi-access=free}}</ref>

{{Unreferenced section|date=August 2020}}
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#Rocks and coal|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]] [[slate]]s 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, Bhutan|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 orogeny|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.

==Climate==
{{Unreferenced section|date=February 2019}}
The climate of the Eastern Himalayas is of a tropical [[Montane ecosystems|montane ecosystem]]. The tropical rainforest climate is hot and wet all year round, with no dry season in the foothills in [[Köppen climate classification|Köppen Climate Classification System]] ([[Tropical rainforest climate|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 {{convert|20|C|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 receive more rain than the drier [[Western Himalaya|Western Himalayas]].

In the valleys of [[Rangeet River|Rangeet]], [[Teesta River|Teesta]], and [[Chumbi valley|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.

==Agriculture==
Agricultural conditions vary throughout the region. In the highlands the soil is [[Moraine|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 economy|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.<ref name="O'Neill_al2017"/>

==Political divisions==
{{Unreferenced section|date=February 2019}}
The Eastern Himalayas consist of 6 distinct political/national territories:
* [[Nepal]]i Himalaya (central, eastern and southern Nepal)
* [[Darjeeling Himalaya|Darjeeling Sub-Himalaya]]
* [[Sikkim|Sikkim (Indian)]] Himalaya
* [[Assam]] Sub-Himalaya
* [[Bhutan]] Himalaya
* [[Arunachal Pradesh]] Himalaya
* [[Uttarakhand|Garhwal/Kumaon]] Himalaya

== Wildlife ==
[[File:Blue Poppy.jpg|thumb|The [[blue poppy]] (''Meconopsis gakyidiana'') is the national flower of Bhutan]]
The Eastern Himalayas sustain a diverse array of wildlife, including many rare species of fauna and flora.<ref name="O'Neill_2019"/> [[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 hotspot]]s. 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.<ref>{{Cite web |title=Himalayas {{!}} Places {{!}} WWF |url=http://www.worldwildlife.org/places/eastern-himalayas |website=[www.worldwildlife.org World Wildlife Fund] |access-date=29 January 2016}}</ref>

The most diverse [[cloud forest]] is in India and China at {{convert|2000-3300|m|abbr=on}}, and [[tropical rainforest]] on the lower slopes up to {{convert|900|m|abbr=on}} in the foothills. At higher elevations, wet [[páramo]] grasslands occur up to {{convert|4500|m|abbr=on}}), and above this elevation snow and ice occupies the space. [[Asian black bear]], [[Himalayan vulture]], and [[pika]]s are common around 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.<ref name="O'Neill_2019"/>

The picture seen right is of the national flower of Bhutan ''[[Meconopsis]] gakyidiana'', 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 [[Hybrid (biology)|hybridize]] with each other and produce viable seeds, causing wider morphological diversity.{{cn|date=August 2020}}

==See also==

* [[Western Himalaya]]
* [[Indus-Yarlung suture zone]]
* [[Main Himalayan Thrust]]
* [[Lower Himalayan Range]]
* [[Ecology of the Himalayas]]
* [[Geology of the Himalaya]]
* [[Sivalik Hills]]
* [[Geography of Myanmar]]
* [[Indian Himalayan Region]]
* [[Jammu and Kashmir (union territory)]]
* [[Transhimalaya]]
* [[Indo-Gangetic Plain]]

== References ==
{{reflist|2}}

==External links==

* [http://www.worldwildlife.org/what/wherewework/easternhimalayas/index.html Eastern Himalayas] – World Wildlife Fund projects

[[Category:Himalayas| ]]
[[Category:Mountain ranges of the Himalayas|.]]
[[Category:Flora of East Himalaya| 01]]
[[Category:Mountain ranges of Asia]]
[[Category:Mountain ranges of India]]
[[Category:Mountain ranges of Myanmar]]
[[Category:Mountain ranges of Nepal]]
[[Category:Mountain ranges of Pakistan]]
[[Category:Mountain ranges of Tibet]]
[[Category:East Asia]]
[[Category:Regions of India]]
[[Category:Regions of Myanmar]]
[[Category:Regions of Nepal]]
[[Category:Physiographic divisions]]

Eastern Himalayas - Revision history

Ajay Kumar at 13:04, 31 August 2023