Department of Environment and Forest


Dihang Dibang Biosphere Reserve

Introduction: The Biosphere Reserve constitutes an area of 5112 Sq. Km in the district of West Siang, Upper Siang and Dibang valley of Arunachal Pradesh. An area of 4095 Sq.Km constitutes the core zone of the BR and 1017 Sq.Km makes the buffer zone. Due to the steep terrain combined with difficult weather as well as the lack of communication, the area has a very sparse human population. The approximately 10,000 people who live here are primarily of the Adi, Buddhist and Mishmi tribes with ten sub tribes including the Paris, Padams, Karkos, Pangis, Simongs, Ashings, Tangams, Komkars, Millangs, Dalbings, Membas, Khambas and Idu Mishmis. The Biosphere Reserve area is almost totally under the cover of vegetation with villages and cultivations located on lower slopes and terraces edging the major river systems. Considerable territory in the BR lies at elevations above the tree line and this area features a very special array of plants and animals. Two of the most exciting facts relating to the forest here is that in most of the Himalayas outside of Arunachal Pradesh one does not find natural vegetation stretching in an unbroken sequence from the tropics to the mountain tundra. Arunachal Pradesh is the finest stronghold for this type of continuity in the Himalayas. Secondly, in contrast to other areas of the Himalayas outside of Arunachal Pradesh, the BR exhibits a wonderful extent of sub-tropical forest. Forests at subtropical levels are the most severely altered in the Himalayas and Arunachal Pradesh is the last stronghold for many Himalayan species dependent on this forest type.

Flora: : The vegetation varies according to habitat. Various factors like climatic, edaphic and biotic factors attributes the condition of forming such habitat. The BR has an altitudinal range from 500 to 6000 mtr and a major factor in determining the plant community. The type of vegetation can such be grouped as 1. Sub-tropical broad leafed forests. 2. Sub-tropical pine forest. 3. Temperate broad leafed forests. 4. Temperate conifer. 5. Sub-alpine woody shrub. 6. Alpine meadow (Mountain tundra) 7. Bamboo brakes. 8. Grass lands.

The Biosphere Reserve forms a part of one of the world’s “Bio-Diversity Hot spots”. Tremendous speciation occurs here with over 1500 species of flowering plants expected. Possibly this site may be the center of origin for some crop plants such as the banana. Many NTFP and economic plants groups occur here. Medicinal, aromatic, timber, fodder and fuel plants could be mentioned. There is a rich representation of orchids, Rhododendrons and Primulas. The rare orchid, Vanda strangeana, lives here as do over 50 species of rhododendrons. For the some plant genera and families, this area may be a part of where they initially diversified (i.e. the cradle of speciation). The Rhododendrons genus may be thought of in this context. The BR provides the rich for all organisms like saprophytes, as Monotropa uniflora, Epipogium spp and Gastrodia spp and parasites such as Boescheckia spp, Galeola spp. Some plants listed in “primitive” families are seen here including Mangletia gaveana, Magnolia campbettii, Schizandra neglecta, Holbelia lotifolia, and various species of Ranunculus. Only a few of the many rare and endangered species here include cyathea spp, Angiopteris spp, living stonia spp, Coptus teeta and Amenototaxus spp. Local medical healers have a remarkable storehouse of knowledge relating to their environment and thus the BR has an important socio-economic signature due to its ethno-biological richness.

Fauna: This BR is very rich and diverse in the population of animal. Some of the species here are endemic to the eastern Himalayas, many of these as well as others are listed at endangered. Some of the spcies as recorded are insects of 45 species including moths and butterflies wre documented Hill trout has been observed among the fishes. There is an impressive array of forest frogs. It is noticed that a wonderful chorus of frogs at some part of the BR forests breaks out just after the dark, often with four or more species calling at the same time. Snakes are present there, mostly non-poisonous except the poisonous green pit vipers (Trimeresurus), cobras (Naja and Ophiophagus) and kraits (Bungarus). The Indians rock python is also known. About 195 species of birds had been recorded. Of these, the scatter’s Monal and Blyth’s Tragopan are among the most interesting. These beautiful pheasants live in a limited range of the eastern Himalayas and are very much threatened. Temminck’s trogopan is also found in this region but no data on this bird is available from the Indian sub-continent. The pale-capped pigeon a globally threatened spp is recorded in this area. Other species, considered rare in parts of the Himalayas, have been found to be comparatively common here. These include the Purple cochoa, Nepal cutia, and Pale Blue Flycatcher. The wedged billed wren babbler family (Timaliidac), has been seen here. Some more interesting observation has been make and these include the water pipit, Japanese Bush warbler, Isabeline wheatear, Black faced, chest nut earned and pine buntings. In addition there is a possible sighting of the Rufous tailed babbler, crysomma poecilvtis, a species new to the Indian sub continent.

The distribution of large animals like tiger is as 1. Tiger is found at lower elevation 2. Spotted or common leopard in with in the range from the tropics to the tree line 3. Clouded Leopard in wet forests at moderate elevations to the snowline and 4. Snow Leopard above the tree line on slopes where blue shup live. Small cats also occur here. The entire north boundary of the BRs the home of elusive and shy Red Panda. One of the most unusual ungulates of the eastern Himalayas and Western Chinese mountains is the Takin. This animal occurs here in small herds that range from 2500 to 4000 mtrs. The endangered Musk Deer also lives at these elevations but is confined to forest. Other includes Bison, Serow, Himalayan Black Bear, Sloth bear, Indian Wild dog, Red fox, Deer, Assamese Macaque, Squirrel, Civet and Wild Board. With such diverse biological potential, spread over more that 5,000 of different bio-zones, the proposed BR is truly a biologist’s dreamland. The tribal population inhabiting this area are in harmony with their environment and have for generations been utilizing their rich bio-diversity for their sustenance.

Department of Forests & Environment, Government of Arunachal Pradesh.
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