Location and General Description
This large ecoregion represents the semi-evergreen submontane rain forests that extend from the midranges of the Arakan Yoma and Chin Hills north into the Chittagong Hills of Bangladesh, the Mizo and Naga hills along the Myanmar-Indian border, and into the northern hills of Myanmar. It divides the Brahmaputra and Irrawaddy valleys, through which two of Asia's largest rivers flow. Some areas in this ecoregion receive more than 2,000 mm of rainfall annually from the monsoons that sweep in from the Bay of Bengal.
An area of deep gorges and dissected landscapes, this mountain range was created 40 to 50 million years ago when the Laurasian mainland crumpled under the inexorable force of the northward-drifting Deccan Plateau; this northeastern corner bore the brunt of the initial contact. These mountains now represent a biogeographic crossroads for the Indian, Indo-Malayan, and Indo-Chinese biotas (Rodgers and Panwar 1988). The ecoregion's position along this ecotone endows it with high biological diversity. These semi-evergreen forests are characterized by several species of Dipterocarpaceae that include Dipterocarpus alatus, D. turbinatus, and D. griffithii, and Parashorea stellata, Hopea odorata, Shorea burmanica, Swintonia floribunda, Anisoptera scaphula, Eugenia grandis, Xylia xylocarpa, Gmelina arborea, Bombax insignis, B. ceiba, Albizia procera, and Castanopsis spp. (FAO 1981). The dense understory includes some evergreen trees and a dense growth of bamboo, such as Cephalostachyum pergracile (tin-wa), Gigantochloa nigrociliata, and Dendrocalamus hamiltonii. In the Arakan area, Melocanna baccifera grows almost monotypic stands and may inhibit forest regeneration. Along stream banks and in low-lying areas, Hopea odorata and Lagerstroemia speciosa dominate.
The Mizoran-Manipur-Kachin Rain Forests [IM0131] ecoregion still retains almost half of its natural habitat. The 149 mammal species known from the ecoregion include two near endemic species: the bat Pipistrellus joffrei and the murid rodent Hadromys humei (table 1). The lower forests in Nagaland harbor two of India's rare primates: the stump-tailed macaque (Macaca arctoides) and the pig-tailed macaque (Macaca nemestrina) (Rodgers and Panwar 1988). The forests of Manipur may still harbor the critically endangered Eld's deer or Thamin (Cervus eldii) (Corbet and Hill 1992). Thamin (Eld's deer) can still enjoy its natural habitat with viable population in northwestern Myanmar. And these large, intact forests have been identified as priority areas for the long-term conservation of the region's largest predator, the majestic tiger Panthera tigris (Dinerstein et al. 1997; Wikramanayake et al. 1998). There are also several threatened species, including the red panda (Ailurus fulgens), Asian elephant (Elephas maximus), clouded leopard (Pardofelis nebulosa), gaur (Bos gaurus), goral (Nemorhaedus goral), great Indian civet (Viverra zibetha), Assamese macaque (Macaca assamensis), capped langur (Semnopithecus pileatus), hoolock gibbon (Hylobates hoolock), back-striped weasel (Mustela strigidorsa), and smooth-coated otter (Lutrogale perspicillata).
Table 1. Endemic and Near-Endemic Mammal Species.
Vespertilionidae Pipistrellus joffrei*
Muridae Hadromys humei
An asterisk signifies that the species' range is limited to this ecoregion.
The ecoregion's large, contiguous habitat areas are included within two high-priority (Level I) TCUs (Dinerstein et al. 1997). Maintaining landscapes with large habitat blocks is important to conserve these large predators, and this ecoregion provides one of few opportunities in the region to do so.
The ecoregion harbors 580 bird species, with 6 being near endemic (table 2). Two EBAs-Eastern Himalayas (130) and Assam Plains (131)-that contain thirteen restricted-range birds them (Stattersfield et al. 1998) overlap with this ecoregion.
Table 2. Endemic and Near-Endemic Bird Species.
Family Common Name Species
Phasianidae Manipur bush-quail Perdicula manipurensis
Timaliidae Striped laughingthrush Garrulax virgatus
Timaliidae Brown-capped laughingthrush Garrulax austeni
Timaliidae Marsh babbler Pellorneum palustre
Timaliidae Tawny-breasted wren-babbler Spelaeornis longicaudatus
Timaliidae Wedge-billed wren-babbler Sphenocichla humei
An asterisk signifies that the species' range is limited to this ecoregion.
Complementing the endemic bird species are four pheasant species (Blyth's tragopan [Tragopan blythii], grey peacock-pheasant [Polyplectron bicalcaratum], green peafowl [Pavo muticus], and Kalij pheasant [Lophura leucomelanos]) and three hornbills (great hornbill [Buceros bicornis], wreathed hornbill [Aceros undulatus], and oriental pied-hornbill [Anthracoceros albirostris]), which are good indicators of intact forests because of their need for mature trees and low thresholds for disturbances.
Almost half of this ecoregion's natural habitat is still intact, especially in the eastern areas within Myanmar. There are fifteen protected areas that cover about 3,700 km2 (3 percent) of the ecoregion (table 3). Nonetheless, several other intact habitats should be incorporated to create a more comprehensive and representative protected area network that includes the diverse habitats and biodiversity contained within this ecoregion.
Table 3. WCMC (1997) Protected Areas That Overlap with the Ecoregion.
Protected Area Area (km2) IUCN Category
Intanki 310 IV
Tamanthi 1,250 UA
Barail 370 PRO
Keibul Lamjao 40 II
Yagoupokpi Lokchao 190 IV
Murlen 200 DE
Khawnglung 40 IV
Phawngpui 50 II
Unnamed 60 ?
Puliebadze 120 IV
Dampa 600 IV
Pablakhali 240 IV
Ngengpui 150 IV
Bogakine Lake WS 10 ?
Kyaukpandaung 140 PRO
Ecoregion numbers of protected areas that overlap with additional ecoregions are listed in brackets.
Types and Severity of Threats
In the past, these forests were logged heavily for their timber. Currently, the primary causes of deforestation are shifting cultivation, although illegal logging still occurs. Cutting trees for fuelwood and fodder, regular burning to encourage new growth for livestock, and overgrazing and trampling by livestock are other overarching threats (FAO 1981). Demand for wildlife and wildlife products from China market is a serious threat to these areas' biodiversity. Lack of enforcement encourages the poachers and wildlife traders. Rarity of tiger in this ecoregions is the result of tiger trade over last two decade.
Justification of Ecoregion Delineation
In a previous analysis of conservation units in the Indo-Malayan realm, MacKinnon (1997) identified a sub-biounit (09b) that covers the Kachin and upper Chindwin areas of northern Myanmar. But this subunit includes several vegetation types in the tropical and subtropical moist broadleaf forest biome in the region. We extracted the semi-evergreen, submontane moist forests into the Mizoram-Manipur-Kachin Rain Forests [IM0131], which then extends east across northern Myanmar to include the full extent of the distribution of these forests. In keeping with our rules for first defining ecoregions based on distinct habitat types and then separating the lowland and montane forests, we used the boundary between the moist deciduous and semi-evergreen forests to define the lowland boundary. We then used the 1,000-m contour from a DEM to define the upper boundary. MacKinnon's westernmost subunit (09c) represents a transition zone between the Indian Subcontinent and Indochina bioregions and is essentially made up of forest formations belonging to the tropical and subtropical moist broadleaf forests biome. We extended this ecoregion to include the lower-elevation tropical moist forests in this subunit.
This region does not correspond well to Udvardy's biogeographic provinces. The Myanmar Coastal Rain Forests [IM0132] cover the Udvardy's Burman rain forest, southwestern portion of the Thai monsoon forest, and western portion of the Indochinese rain forest. The Irrawaddy Moist Deciduous Forests [IM0117], Irrawaddy Dry Forests [IM0205], Chin Hills-Arakan Yoma Montane Rain Forests [IM0109], Northeast India-Myanmar Pine Forests [IM0303], Northern Triangle Subtropical Forests [IM0140], and Mizoram-Manipur-Kachin Rain Forests [IM0131] correspond roughly to Udvardy's Burman rain forest and Burma monsoon forest.
References for this ecoregion are currently consolidated in one document for the entire Indo-Pacific realm.
Indo-Pacific Reference List
Prepared by: Eric Wikramanayake and U Tin Than