Location and General Description
The ecoregion represents the subtropical forests of the Khasi and Garo hills that rise to more than 1,800 m in the eastern Indian states of Meghalaya and Assam. These hills were geologically part of the Deccan Plateau. Therefore, the ecoregion has ancient Gondwanaland origins.
The dominant substrate is a low-nutrient acrisoil, but the high rainfall-parts of the Khasi Hill can receive more than 11 m of annual rainfall-and local climatic variation as a result of the complex landform have promoted high biological diversity and centers of endemism here (Rodgers and Panwar 1988). The endemic pitcher plant Nepenthes khasiana, which is confined to the Khasi Hills, is but one example of the many plant species with very limited range distributions.
The major forest types in this ecoregion, according to Champion and Seth (1968), are Assam subtropical hill savanna, Khasi subtropical hill forest, Assam subtropical pine forest, and Assam subtropical pine savanna. More recently, Haridasan and Rao (1985) described the forest vegetation in this area as consisting of tropical evergreen forests in low-lying areas with high rainfall and characterized by species such as Bischofia javanica, Fermiana colorata, Pterygota alata, Mesua ferrea, Castonopsis indica, Talauma hodgsonii, Pterospermum acerifolium, and Acrocarpus fracinifolius; tropical semi-evergreen forest (up to elevations of 1,200 m) where annual rainfall is 1,500-2,000 mm and typical species include Eleocarpus floribundus, Dillenia pentagyna, Dillenia indica, Hovenia acerba, and Lithocarpus fenestratus; tropical moist and deciduous forests in areas with less than 1,500 mm rainfall and characterized by Shorea robusta, Tectona grandis (most likely from plantations), Terminalia myriocarpa, Tetrameles nudiflora, Schima wallichii, and Albizzia lebbeck; grasslands and savanna of Saccarum spontaneum, Neyraudia reynaudiana, Chrysopogon aciculatus, and Setaria glauca on the tops of the Khasi, Jaintia, and Garo hills; isolated patches of temperate forests of Lithocarpus fenestratus, Castanopsis kurzii, Quercus griffithii, Quercus semiserrata, Schima khasiana, and Myrica esculenta along the southern slopes of the Khasi and Jaintia hills; and subtropical pine forests with pure stands of Pinus khesia confined to the higher reaches of the Shillong Plateau.
The mature forests have a dense undergrowth of patches of bamboos and canes (Rao 1991), with Dendrocalamus hamiltonii being especially common (Puri et al. 1989). The trees are draped in climbers and epiphytes (Puri et al. 1989; WWF and IUCN 1995).
More than 110 mammal species are known from the Meghalaya Subtropical Forests [IM0126], but none are endemic to this ecoregion. Some of the species of conservation importance represented here include the tiger (Panthera tigris), clouded leopard (Pardofelis nebulosa), Asian elephant (Elephas maximus), wild dog (Cuon alpinus), Malayan sun bear (Ursus malayanus), sloth bear (Melursus ursinus), smooth-coated otter (Lutrogale perspicillata), large Indian civet (Viverra zibetha), Chinese pangolin (Manis pentadactyla), Indian pangolin (Manis crassicaudata), Assamese macaque (Macaca assamensis), bear macaque (Macaca arctoides), capped leaf monkey (Semnopithecus pileatus), and hoolock gibbon (Hylobates hoolock). The tiger, clouded leopard, Asian elephant, Assamese macaque, bear macaque, capped leaf monkey, wild dog, sloth bear, and smooth-coated otter are threatened species (IUCN 2000).
Despite the sparse large mammal fauna, the small mammals are well represented, especially the bats and the small carnivore community, which is unrivaled (Rodgers and Panwar 1988) across this bioregion. The ecoregion's position at the interface between different regional faunas is apparent with the overlap between similar species with different range distributions (e.g., the Indian and Chinese pangolins and the Malayan sun bear and sloth bear).
The bird fauna is richer, with more than 450 species. These include five species that are endemic to the ecoregion (table 1). All these species are near endemic (i.e., shared with adjacent ecoregions).
Table 1. Endemic and Near-Endemic Bird Species.
Family Common Name Species
Phasianidae Manipur bush-quail Perdicula manipurensis
Timaliidae Marsh babbler Pellorneum palustre
Timaliidae Brown-capped laughingthrush Garrulax austeni
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.
The ecoregion also harbors the globally threatened rufous-necked hornbill (Aceros nipalensis) and several other threatened species, including the white-winged duck (Cairina scutulata), ferruginous pochard (Aythya nyroca), Pallas's fish-eagle (Haliaeetus leucoryphus), marsh babbler (Pellorneum palustre), tawny-breasted wren-babbler (Spelaeornis longicaudatus), Manipur bush-quail (Perdicula manipurensis), bristled grassbird (Chaetornis striatus), Blyth's kingfisher (Alcedo hercules), greater spotted eagle (Aquila clanga), black-breasted parrotbill (Paradoxornis flavirostris), dark-rumped swift (Apus acuticauda), and beautiful nuthatch (Sitta formosa).
Several of the other hornbill species-wreathed hornbill (Aceros undulatus), brown hornbill (Anorrhinus tickelli), and great hornbill (Buceros bicornis)-are indicators of intact and mature habitat; these birds depend on tall, mature trees for nesting, without which the populations will decline.
The ecoregion also overlaps with two of BirdLife International's EBAs, Assam Hills (131) and Eastern Himalayas (130) (Stattersfield et al. 1998), attesting to the rich bird fauna with limited breeding ranges.
More than two-thirds of this ecoregion has been cleared or degraded; however, extensive stretches of intact habitat can still be found in the northeastern parts. The protected area system in this ecoregion amounts to a mere 154 km2, which is less than 1 percent of the ecoregion's area (table 2). All seven protected areas are extremely small, with the largest being only 60 km2. However, several patches of habitat are included within sacred forests that have been traditionally protected (Rao and Haridasan 1982).
Table 2. WCMC (1997) Protected Areas That Overlap with the Ecoregion.
Protected Area Area (km2) IUCN Category
Nokrek 50 II
Siju Wildlife 10 IV
Balphakram 10 II
Baghmara Pitcher Plant 10 IV
Nongkhyllem 10 IV
Garampani 60 IV
Rangapahar 4 IV
Ecoregion numbers of protected areas that overlap with additional ecoregions are listed in brackets.
Two protected areas are of special interest in this ecoregion: Baghmara pitcher plant sanctuary (about 0.1 km2 for the protection of Nepenthes khasiana) and the small Nokrek National Park in the Garo Hills, known for its rich evergreen forests containing wild Citrus spp. Among the glaring protection gaps are large habitat areas that will allow the important elephant populations in Assam to undertake unhindered seasonal migrations (Rodgers and Panwar 1988).
Types and Severity of Threats
The primary threats to this ecoregion's biodiversity stem from the following. Deforestation is a huge factor, especially that which results from shifting cultivation in and around the remaining blocks of forests. Hunting for tigers and elephants is rife. Mining for coal and limestone along the migratory routes of elephants will threaten their traditional movements (Johnsingh and Williams 1998) and result in escalating human-elephant conflicts that are already intense. These lands have been leased by the tribal landholders to private mining companies.
Justification of Ecoregion Delineation
Rodgers and Panwar (1988) delineated the northeastern region of India into two units, of which one, Assam Hills (8B), included the Manipur Hills to the west. Subsequently, MacKinnon (1997) split unit 8B into two biounits, the Northeast Hills (I9b) and the Burma transition (09c). The former represents a distinct vegetation type in the hills of Meghalaya, as depicted in MacKinnon's reconstruction of the original vegetation in the region. Therefore, we retained this biounit, with very slight modification, as the Meghalaya Subtropical Forests [IM0126]. We used MacKinnon's (1997) digital map of the original vegetation, aided by a DEM, to draw the boundaries of the ecoregion to include the subtropical forests above 1,000 m in elevation. This ecoregion overlaps with two of Udvardy's biogeographic provinces: the Himalayan highlands 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: Gopal S. Rawat and Eric D. Wikramanayake