Western Ghats Southern Asia : Lush Tropical Evergreen Forest

Many years ago, the Malabar Coast Moist Deciduous Forests [IM0124] ecoregion was a swath of lush tropical evergreen forest that extended along the western coast of the Deccan Peninsula between the Western Ghats Mountains and the Indian Ocean (Champion and Seth 1968). These forests were once inhabited by tigers (Panthera tigris), Asian elephants (Elephas maximus), wild dogs (Cuon alpinus), sloth bear (Melursus ursinus), and a host of hornbills. But today very little of the natural habitat is left (Rodgers and Panwar 1988), the result of years of forest clearing to establish teak (Tectona grandis) plantations, human settlements, and other human activities such as fires set to clear forests for agriculture and promote grazing lands for livestock. Therefore, the original evergreen character of the forests has changed from the evergreen vegetation to a semi-evergreen condition (Champion and Seth 1968). Many of the large, space-dependent species have disappeared from the ecoregion, victims of habitat loss and fragmentation. This is another ecoregion on the verge of extinction.

SCIENTIFIC CODE

(IM0124)

ECOREGION CATEGORY

Indo-Malayan

SIZE

13,700 square miles

STATUS

Critical/Endangered

HABITATS

Description 

Location and General Description

The ecoregion represents the semi-evergreen forests along India's Malabar Coast, a narrow strip of land lying between the Indian Ocean to the west and extending up to the 250-m contour of the steep Western Ghats Mountains to the east (after Rodgers and Panwar 1988). It extends through the Indian states of Kerala, Karnataka, and Maharashtra.

Geologically, the Deccan Plateau-and thus the ecoregion-has Gondwanaland origins. After the Deccan Plate became detached and drifted northward to attach itself to the northern Eurasian continent, the Western Ghats Mountains were created by geological uplift. The mountains then began to intercept the southwestern monsoon rains, creating moister conditions on the western slopes of the range and drier conditions on the eastern side.

The southwestern monsoon brings more than 2,500 mm of annual rainfall to the ecoregion, influencing the vegetation. The southern parts of the ecoregion, in Kerala State, receive more rainfall, and the vegetation has responded by being tropical wet evergreen in the south with a gradual trend tending to drier conditions to the north.

The original vegetation along the west coast of the Deccan Peninsula was tropical evergreen (Champion and Seth 1968). But the forests have been largely replaced or interspersed with teak, giving the vegetation a semi-deciduous character; the teak is now considered indicative of a secondary successional stage or presence of plantations.

Champion and Seth (1968) characterized these southern moist mixed deciduous forests with the following species: Tetrameles nudiflora, Stereospermum personatum, Dysoxylum binectariferum, Ficus nervosa, Ficus glomerata, Pterocarpus marsupium, Salmalia malabarica, Terminalia bellerica, Terminalia tomentosa, Anogeissus latifolia, Dalbergia latifolia, Lannea coromandelica, Madhuca indica, Garuga pinnata, Syzygium cumini, Olea dioica, Pouteria tomentosa, Bridelia retusa, Mangifera spp., and Actinodaphne angustifolia. There is generally a second story of Erythrina variegata, Butea monosperma, Wrightia tinctoria, Bauhinia racemosa, and Zizyphus rugosa and a shrub layer of Flacourtia spp., Woodfordia fruticosa, Meyna laxiflora, and Carissa congesta (Puri et al. 1989). Along the northern coast of Karnataka State several patches of moist deciduous forests are represented by an association of Lagerstroemia microcarpa, Tectona grandis, and Dillenia pentagyna (Pascal et al. 1982), representing the drier climatic conditions. The Myristica swamps and the inland lagoons represent distinct habitat types within this ecoregion (Rodgers and Panwar 1988) that are now endangered.

Biodiversity Features

The ecoregion's mammal fauna, estimated at ninety-seven mammal species, includes five near-endemic species and a single small rodent species that is strictly endemic to this ecoregion (table 1). The near-endemic species are shared with the ecoregions along the Western Ghats Mountain Range. Many of the other species, especially the larger mammals, are widespread throughout the Indian subcontinent but are threatened by shrinking habitat. The threatened species include the Asian elephant, gaur (Bos gaurus), slender loris (Loris tardigradus), wild dog, sloth bear, Jerdon's palm civet, and grizzled giant squirrel (Ratufa macroura). The habitat in this ecoregion is too fragmented to harbor viable populations of wide-ranging species such as tigers (Wikramanayake et al. 1999). Elephants no longer roam the forests of this ecoregion, although one of India's most important elephant populations ranges along the Nelliampathi Hills (Sukumar 1989) adjacent to the southern parts of this ecoregion

Table 1. Endemic and Near-Endemic Mammal Species.

Family Species 

Soricidae Suncus dayi 

Cercopithecidae Semnopithecus johnii 

Viverridae Viverra civettina 

Viverridae Paradoxurus jerdoni 

Muridae Petinomys fuscocapillus 

Muridae Rattus ranjiniae*

An asterisk signifies that the species' range is limited to this ecoregion.

The ecoregion has an estimated 280 bird species, including one near-endemic species, the Malabar grey hornbill (Ocyceros griseus), which is shared with the submontane and montane ecoregions of the Western Ghats Mountains (table 2).

Table 2. Endemic and Near-Endemic Bird Species.

Family Common Name Species 

Bucconidae Malabar grey hornbill Ocyceros griseus

An asterisk signifies that the species' range is limited to this ecoregion.

The ecoregion also harbors several other species of conservation importance, including the globally threatened lesser florican (Eupodotis indica), a grassland species whose range fringes on this ecoregion. Other species such as the greater flamingo (Phoenicopterus ruber), Indian grey hornbill (Ocyceros birostris), and great hornbill (Buceros bicornis), though not threatened, are nevertheless sensitive to disturbances and can be used as focal species for conservation.

Current Status

More than 95 percent of the ecoregion's natural habitat has been cleared or converted. The moist southern forests have been converted into coconut plantations and rice paddies and the northern forests into teak, rosewood, and rubber plantations. No large blocks of intact forest habitat now exist, although several smaller forest fragments have been preserved by local people as sacred groves.

The three protected areas in this ecoregion cover a mere 300 km2 

Table 3. WCMC (1997) Protected Areas That Overlap with the Ecoregion.

Protected Area Area (km2) IUCN Category 

Sanjay 50 II 

Bhagwan Mahavir 150 IV 

Peechi Vazhani 100 IV 

Total 300  

Ecoregion numbers of protected areas that overlap with additional ecoregions are listed in brackets.

Types and Severity of Threats

Most of the natural forest in this ecoregion has been converted to agriculture and plantations. Extensive teak plantations have created a semi-deciduous vegetation where there used to be evergreen forests. The unique Myristica swamps, limited to parts of northern Karnataka (e.g., Kumta) and Kerala and close to the coast, are being converted to areca and coconut plantations.

Continuing threats to this ecoregion include habitat damage from livestock grazing and trampling. The pastoralists themselves also overexploit the fodder trees and burn large areas to create grasslands. In Karnataka State, huge herds of domestic livestock have become uncontrollable. Meanwhile, Sanjay National Park in Maharashtra is subject to more than a hundred fires every year, and the park staff is not equipped to fight them.

Hydroelectric projects have also flooded large areas of forests; for instance, eleven dams have been constructed along the Periyar River, one of the largest waterways in the state of Kerala. Secondary effects of the dam projects, such as roads, have also allowed more human encroachment, which is causing serious fragmentation of the remaining forests (IUCN 1991).

Justification of Ecoregion Delineation

In an earlier analysis of conservation units of India, Rodgers and Panwar (1988) delineated the coastal moist deciduous forests along the western coast of India as a single conservation unit, the Coastal Plain (5A). In a subsequent regional analysis, MacKinnon (1997) also recognized this unit as a distinct biounit. We retained their classification and placed the lowland moist deciduous forests in the Malabar Coast Moist Deciduous Forests [IM0124]. In doing so, we used MacKinnon's (1997) map of the original vegetation to delineate the ecoregion boundaries. This ecoregion falls within Udvardy's Malabar rain forest biogeographic province.

References

References for this ecoregion are currently consolidated in one document for the entire Indo-Pacific realm.

Indo-Pacific Reference List