Status and Distribution of Primates in Arunachal Pradesh - D. N. Singh
Introduction
Arunachal Pradesh is situated between 26°– 29° N to 29°–30’ N (latitudes) and 91°–30’ E (longitude) covering a geographical area of 83,743 km2. It is the largest of the 7 states in Northeast India. The state is mostly hilly and flanked by Tibet in the north; separated by McMohan Line, by Bhutan in the west, by China and Myanmar in the east and by the Indian states of Assam and Nagaland in the south. It is predominately a tribal state with more than 82 major tribes and sub-tribes of Indomongoloid and Mongoloid lineage residing in the state, and who are largely dependent on forest resources for their sustenance. However, because of sparse population density (10 persons/km2 as per 1991 Census), the tribal people of this state have been living in perfect harmony with forests for centuries. This harmonious relation between the people and forests has been disturbed in recent times due to increasing pressures from human populations, and large developmental projects which have been taken up to give a boost to the region’s economy.
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Abstract The northeastern state of Arunachal Pradesh which constitutes the major portion of the eastern Himalayas, is one of the two biodiversity hot spots in India, of 25 global biological diversity hot spots all over the world. Arunachal Pradesh is home to 4 genera and 8 species of non-human primates. The common langur (Seminopithecus entellus), has not been observed during this study, although in some literature it has been reported from this state. The snub-nosed monkey (Rhinopithecus roxellanae), a Chinese species, is also reported from the higher elevations along the Indo-China and Indo-Myanmar borders. The present communication attempts to study distribution and present status of primates in Arunachal Pradesh. |
Physiographically, the state is divided into 3 sections, viz., the flood plains of the mighty Brahmaputra river and its tributaries, the foothills of the Shivalik range and Changlang districts (Patkal range), which is not part of the eastern Himalayas.
Biogeographically, the entire state is located in the Oriental and the Palearctic Bio geographic realm of the Indian sub-continent biogeographic region. It is in the Himalayan biogeographic zone and the eastern Himalaya (2D) biogeographic province (Rodgers & Panwar, 1988). However, the entire Tirap district of the state and the part of Changlang district, falling south of Chokan Pass and Noa- Dehing (Diun) river are situated in the Patkai Mountain Range. As such bio geographically, this belt of the state falls under the northeast Hills (9B) biogeographic province, of the northeast India Zone (Rodgers & Panwar, 1988). The state is also bio geographically important because it falls in the transition zone between the Indian sub continent and Indo-Chinese biogeographical regions (Dinnersteni et. al., 1997).
The state has a wide altitudinal variation ranging from 50 m, in the foothills to about 7,000 m along its northern parts. The highest peak (7,090 m) is in the northwestern Tawang district of the state. The area is drained by a number of rivers and rivulets, the important ones being the Kameng, the Subansiri, the Siang (Tsangpo in Tibet), the Dibang, the Lohit, the Noa-Dehing (Diyun) and the Tirap. All these rivers give rise to the mighty Brahmaputra.
The state also falls in one of the heaviest rainfall zones of the country. The annual rainfall is spread over 8–9 months and varies from 1,000 mm in the higher reaches to 3,500 mm in the foothills. The pre-monsoon showers start from March, the monsoons being active from May to September, and the retreating monsoon showers are received during October and November, with the humidity during the rainy season rising up to 90%. This diversity of topographical and climatic conditions has favoured the growth of luxuriant forests, which are home to a myriad plant and animal forms. Consequently, 3 broad climatic zones are recognized viz. the hot and humid sub-tropical areas at the foothills, the cooler temperature zone of the lesser Himalayas and the alpine zone of the greater Himalayas. The soil in the major parts of the state are rocky consisting of shales, schist and conglomerates. In the lower elevations of the valleys, it is acidic due to high rainfall but rich in humus content. The vegetation of Arunachal Pradesh is classified into 5 broad forest types and a distinct secondary forest type, largely man-made (Anon., 1999). These are:
1. Tropical Forests
(a) Tropical Evergreen Forests
(b) Tropical semi-evergreen Forests
2. Sub-tropical Forests
3. Pine Forests
4. Temperate Forests
(a) Temperate Broad-leaved Forests
(b) Temperate Conifer Forests
5. Alpine Forests
6. Secondary Forests
(a) Degraded Forests
(b) Bamboo Forests
(c) Grasslands
The varying climatic and altitudinal conditions that range from tropical to alpine climate offer conditions congenial to the growth of a wide range of flora thereby providing food and cover to many wild animals.
Primates in India, are represented by 7 genera, 15 species and 39 subspecies, which is 12% of the world’s total species and subspecies of non-human primates. In Northeast India, 5 genera and 11 species of non-human primates are found, and Arunachal Pradesh is home to 4 genera and 8 species of nonhuman primates. Chatterjee and Chandiramani (1986), Mehta (1987), and Chatterjee (1989) have reported the presence of the common langur (Semnopitheus entellus) in the state. However, during the present study no sighting or anecdotal records of the Common langur in the state were made. The Common langur has not been reported from the Northeast region (Choudhary, 1989), but for the state of Tripura and Sikkim (Borang & Thapliyal, 1993). The Snub-nosed monkey (Rhinopitchecus roxellanae) from China has been reported in the past from Manipur and northern Assam in the northeast by Roonwal & Mohnot (1977) and Roonwal (1989). It may stray into the higher elevations. However, this species has been reported from the forests of Tawang district of Arunachal Pradesh bordering China (T. Riba, DFO Tawang, pers. comm.).
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1. Slow Loris (Nycticebus coucang) Distribution: The Slow loris is found throughout the state mainly in the dense tropical forests up to an elevation of 800–900 m. Status: Although, no status survey has been done in the state, deforestation due to jhumming, developmental projects and timber felling in the tropical forests all over the state is likely to cause irreparable damage to its habitat. Therefore, the species is under serious threat in the state. |
2. Rhesus Macaque (Macaca mulatta)
Distribution: It is the most common primate species of the state recorded from low-lying land at the foothills to an elevation of 1,000 m in all major vegetation types. For a distribution map, refer to A.K. Gupta in this issue.
Status: Status surveys have not been done in this state, however, there is need for better protection of its habitat, as the long term survival of this species is completely dependent on forests, unlike the Rhesus of northern India who are also found in cities and villages. The bold and aggressive Rhesus macaque is very shy and secretive throughout Arunachal Pradesh and it is rare to see a Rhesus macaque coming near humans in this state. This changed behaviour is due to hunting by the tribal people for food, medicine and other ethno-zoological reasons.
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3. Assamese Macaque (M. assamensis) Distribution: It is the second most common primate species, next to Rhesus, in Arunachal Pradesh. It is found in all types of dense forests including bamboo forests starting from the foothills to an altitude of 2,000 m. Status: Status surveys of this macaque are lacking, however, the present population of this species in the state is under threat due to destruction and damage being caused to its habitat. These macaques are hunted by the tribal people of the state for food and for medicinal purposes. The Adi tribes of Arunachal Pradesh eat the flesh of this macaque during epidemic diseases. Some parts of the body (palm, fingers and skull) are hung at the main door of the house to keep away evil forces and spirits. |
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4. Stump-tailed Macaque (M. arctoides) Distribution: The Stump-tailed macaque inhabits the tropical wet evergreen and tropical semi-evergreen moist forests of Tirap, Changlang and Lohit districts extending up to the south bank of the Lohit river in Arunachal Pradesh. This range falls within the Mishmi Hills and the Patkai Ranges. It is found in 2 Protected Areas of the state, namely the Namdapha National Park (Tiger Reserve) and the Kamlang Wildlife Sanctuary. Status: Sightings of this macaque are very rare with very few records in the Namdapha National Park (4 sightings of the troop by the author in a span of two and a half years, and 2 additional sightings by the research staff of Namdapha Tiger Project, pers. comm. A.K. Das). It is imperative to mention here that the habitat of this species in the Tirap and Changlang district is under serious threat due to jhumming and large-scale deforestation and clearing of the forests for tea cultivation. These macaques have been observed to move in groups. In Namdapha National Park the author saw one troop consisting of 13 individuals in the forests between M’Pen and Gibbons land. They were observed feeding on the grounds while some were on the tree branches.
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Map to be inserted |
5. Pig-tailed macaque (M. nemestrina)
Distribution: The Pig-tailed macaque is found in the tropical rainforests in the Tirap and the Changlang districts of Arunachal Pradesh. The author as well as other research personnel have sighted this macaque in the rainforests of the Namdapha. For a distribution map refer to A.K. Gupta in this issue.
Status: The sightings of the Pig-tailed macaque are rare with only 2 sightings in two and a half years inside Namdapha (January 1998– June 2000) by the author. An extensive survey is required in all the Tirap and Changlang districts to ascertain its present status. It is restricted to only one Protected Area throughout the state, the Namdapha National Park.
6. Capped Langur (Trachypithecus pileatus)
Distribution: This species is found all over the state, inhabiting the tropical semi-evergreen, moist evergreen and deciduous forests, except for the strip of the land falling in between the Siang and the Dibang rivers. For a distribution map refer to A.K. Gupta in this issue.
Status: The Capped langur is a very common primate species in the state, after the Rhesus and the Assamese macaque. However, it is under tremendous threat due to deforestation and poaching for food and medicine.
7. Snub-nosed Monkey (Rhinopithecus roxellanae)
Distribution: The Snub-nosed monkey is found in Szechuan and Sikang provinces of China and Upper Myanmar. This species strays into the higher altitudes of the state adjoining China and Myanmar. It has been sighted in the Tawang district and Vijoynagar Circle of Arunachal Pradesh bordering China and Upper Myanmar. Sri R. Riba (DFO Tawang), and his staff have sighted this monkey in the forests of the Tawang Forest Division. It has been hunted during November 1997 by a hunter belonging to the Lisu tribe from the higher reaches of the mountains surrounding Vijoynagar Circle in the Changlang district bordering Upper Myanmar. (Sri Phuyosa Ngwazah, Lisu tribe of Vijoynagar Circle, Namdapha Tiger Project, pers. comm.).
Status: This primate strays into the bordering areas of Arunachal Pradesh from China. However, it can be found in the Dibang Valley and Upper Siang district of Arunachal Pradesh bordering China.
8. Hoolock or White-browed Gibbon (Bunopithecus hoolock)
Distribution: The only ape species in India, it is confined to the southern and the eastern parts of the state in the dense tropical semi-evergreen, wet evergreen and moist deciduous forests of Tirap, Changlang, Lohit and Dibang Valley districts, while it is not reported west of the Dibang river. Earlier it has been reported in Subansiri district during the Subansiri Expedition of ZSI in 1974–75 (Borang & Thapliyal, 1993). However, during the present study no report, evidence or sightings of the species were recorded anywhere west of the Dibang river. This ape is confined to the south and the east bank of the Dibang–Brahmaputra river system.
Status: Although no survey has been carried out to know the exact status, it is under serious threat due to poaching and habitat destruction. Although sighted in the forests throughout its range, troops of Hoolocks are larger in the Namdapha Tiger Reserve and the Kamlang Wildlife Sanctuary.
Discussion
Rhesus and Assamese macaques are the 2 most common primates found in the state. Although, the habitat of these 2 species are similar, hunting by the tribals of the state has made the Rhesus macaque shy and wary of the humans, unlike its behaviour in other parts of India, where it is closely associated with the human settlements and is largely found in and around cities and villages. The Capped langur is also found all over the state except for the strip of the land between the Siang and the Dibang rivers. The Snub-nosed monkey is found in the high mountains along the Indo-China and the Indo-Myanmar border. The probability of this primate inhabiting the high mountains in the Dibang Valley, the Upper Siang and the Kurung–Kurmey district is very high since it has been observed in the Tawang district.
The Slow loris is rare and found in the dense tropical rainforests all over the state. The Hoolock gibbon is restricted to the eastern and the southern parts of the state, east of the Dibang river. The population of this species has gone down drastically over the years, which is evident from the fact that the frequency of its songs has become rare. The Pig-tailed and Stump-tailed macaques inhabit the tropical wet-evergreen and semi-evergreen forests of the Tirap, the Changlang and the part of Lohit district south of the Lohit river. However, the population of these 2 species is not dense in their habitats in the state.
Conservation Threats
The main conservation threats to the primates’ populations in the state are: Shifting cultivation: Practised in the state up to an elevation of 2,000 m. It is important to note that all primates are also distributed up to an elevation of 2,500 m. Thus, the burden of shifting cultivation is more on the habitat of non-human primates in addition to other wild animals in the state. It is estimated that the area under shifting cultivation in the state is > 920 km2 in any given year. Shifting cultivation is practised more in the Subansiri, Papumpare, Siang, Lohit, Tirap and Changlang belts ranging from tropical wet evergreen forests to pine forests. The cycle of shifting cultivation was 3 years in Tirap and Changlang, 6 years in Lohit and Siang and 10 years in the Subansiri area has now reduced considerably to 2–4 years everywhere causing immense damage to the habitat of primates. Shifting cultivation is somewhat beneficial to successful colonizer species, such as Rhesus macaques, but is largely harmful to most other species, which are unable to adopt.Development activities: The planner and leaders of this remote and backward area are trying hard to develop the infrastructure sector, thereby accelerating the pace of economic development. Consequently, construction of roads, bridges, dams, hydel power projects and development of townships has been taken up on a large scale. Such developmental projects in these hilly areas have been taken up without any Environmental Impact Assessment. The result is deforestation, soil erosion and damage to the ecological balance. In the economically backward districts of Tirap and Changlang, tea plantations are being carried out along the steep slopes. All these activities are a potent threat to the future of primates. Although the tribal people of this area are backward and their quality of life needs to be improved, a balance needs to be maintained between development and environmental conservation.
Hunting: The tribal people of Arunachal Pradesh occasionally hunt primates for medicinal purpose or to save their crops (Borang & Thapliyal, 1993). However, some tribes also practise hunting for meat. The low population density of the tribals compared to large forest areas in the past did not pose any threat to the population of primates. Nevertheless, over the years, their population has increased due to better medical aid. Added to this, is the fact that large-scale deforestation has taken place due to greater demand for timber. Thus, with the increase in the local population, the forestland available per capita is going down. Consequently, the delicate balance between man and environment is under threat.
Need for Future Work
There is an urgent need for quantitative information on the status, habitat and demographic profile of the primates in the state. Given the nature and the extent of habitat fragmentation and the fact that a majority of the remaining forests are in the form of fragments, it is essential that corridors be developed between these widely spaced small fragments of forests, for the long-term survival of primates. Apart from this it is equally important that conservation education and awareness programmes be carried out in the state to increase the awareness levels in the local communities. Environment Impact Assessment studies need to be commissioned that would look into the impacts of development projects on the forests and its fauna and flora in the state. This would minimize the negative impacts of future development projects on the states’ forests.References
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